* [PATCH -mm 00/24] VM pageout scalability improvements (V12)
@ 2008-06-11 18:42 Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 01/24] vmscan: move isolate_lru_page() to vmscan.c Rik van Riel
` (24 more replies)
0 siblings, 25 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
Andrew, this is the promised drop-in replacement for the patch series,
with all the cleanups you requested since friday as well as the bugfixes
I came up with this morning.
You can drop vmscan-add-some-sanity-checks-to-get_scan_ratio.patch
and the incremental changes - those are all folded in to these patches.
On large memory systems, the VM can spend way too much time scanning
through pages that it cannot (or should not) evict from memory. Not
only does it use up CPU time, but it also provokes lock contention
and can leave large systems under memory presure in a catatonic state.
This patch series improves VM scalability by:
1) putting filesystem backed, swap backed and unevictable pages
onto their own LRUs, so the system only scans the pages that it
can/should evict from memory
2) switching to two handed clock replacement for the anonymous LRUs,
so the number of pages that need to be scanned when the system
starts swapping is bound to a reasonable number
3) keeping unevictable pages off the LRU completely, so the
VM does not waste CPU time scanning them. ramfs, ramdisk,
SHM_LOCKED shared memory segments and mlock()ed VMA pages
are keept on the unevictable list.
More info on the overall design can be found at:
http://linux-mm.org/PageReplacementDesign
An all-in-one patch can be found at:
http://people.redhat.com/riel/splitvm/
Changelog:
- fix the merge bugs
- leave swappiness at 60, if only to demonstrate why that value is
wrong with the new code (hi Andrew)
- update Documentation/vm/unevictable-lru.txt until my hands hurt
from typing
- rename try_to_unlock to try_to_munlock
- remove CONFIG_NORECLAIM_MLOCK, only use CONFIG_UNEVICTABLE_LRU
- Aunt Tillified the CONFIG_UNEVICTABLE_LRU description
- make CONFIG_NORECLAIM_LRU no longer depend on 64BIT and default y
- rename NORECLAIM to UNEVICTABLE as suggested by Andrew Morton
- fix vmscan-fix-pagecache-reclaim-referenced-bit-check.patch so
the referenced bit set test is the same as the shrink_page_list test
- add comments everywhere
- rename inactive_anon_low to inactive_anon_is_low
- use an array for lru stats in meminfo_read_proc
- pull patch 08/25 into 06 and 07 to ease reviewing
Andrew: please remove vmscan-add-some-sanity-checks-to-get_scan_ratio.patch
- rename page_file_cache to page_is_file_cache
- pull page_lru() into patch 02/25 (Rik van Riel)
- use NR_LRU_BASE and LRU_BASE as base for calculations
- make zone->lru stuff cache friendly as suggested by Andrew Morton
- merge in all of Lee's mlock changes
- fix shrink_list memcgroup balancing (KOSAKI Motohiro)
- fix balancing stats in shrink_active_list (Daisuke Nishimura)
- make sure previously active pagecache pages get reactivated
on the first access (Rik van Riel)
- compile fix when !CONFIG_SWAP (MinChan Kim)
- clean up page-flags.h defines when !CONFIG_NORECLAIM_LRU
(Lee Schermerhorn)
- fix some race conditions around moving pages to and from
the noreclaim list (Lee Schermerhorn, KOSAKI Motohiro)
- use putback_lru_page() for page migration (Lee Schermerhorn)
- fix potential SHM_UNLOCK race in scan_mapping_noreclaim_pages()
(Lee Schermerhorn, KOSAKI Motohiro)
- improve swap space freeing to deal with COW shared space
(Lee Schermerhorn, Daisuke Nishimura & Minchan Kim)
- clean up PG_swapbacked setting in swapin path (Minchan Kim)
- properly invoke shrink_active_list for background aging (Minchan Kim)
- add authorship info to all patches (Rik van Riel)
- clean up (or move below ---) the comments for the commit logs (Rik van Riel)
- after some tests, reduce default swappiness to 20 for now (Rik van Riel)
- several code cleanups (minchan Kim)
- noreclaim patch refactoring and improvements (Lee Schermerhorn)
- several PROT_NONE and vma merging fixes (KOSAKI Motohiro)
- SMP bugfixes and efficiency improvements (Rik van Riel, Lee Schermerhorn)
- fix NUMA node stats printing (Lee Schermerhorn)
- remove the mlocked-VMA-noreclaim code for now, it still has
bugs on IA64 and is holding up the merge (Rik van Riel)
- make page_alloc.c compile without CONFIG_NORECLAIM_MLOCK (minchan Kim)
- BUG() does not take an argument (minchan Kim)
- clean up is_active_lru and is_file_lru (Andy Whitcroft)
- clean up shrink_active_list temp list names (KOSAKI Motohiro)
- add total active & inactive memory totals for vmstat -a (KOSAKI Motohiro)
- only try global anon page aging on global lru scans (KOSAKI Motohiro)
- make function descriptions follow the kernel-doc format (Rik van Riel)
- simplify mlock_vma_pages_range and munlock_vma_pages_range (Lee Schermerhorn)
- remove some more arguments, rename to mlock_vma_pages_all (Lee Schermerhorn)
- many code cleanups (Lee Schermerhorn)
- pass correct vma arg to mlock_vma_pages_range from do_brk (Rik van Riel)
- port to 2.6.25-rc3-mm1
- pull the memcontrol lru arrayification earlier into the patch series
- use a pagevec array similar to the lru array
- clean up the code in various places
- improved pageout balancing and reduced pageout cpu use
- fix compilation on PPC and without memcontrol
- make page_is_pagecache more readable
- replace get_scan_ratio with correct version
- merge memcontroller split LRU code into the main split LRU patch,
since it is not functionally different (it was split up only to help
people who had seen the last version of the patch series review it)
- drop the page_file_cache debugging patch, since it never triggered
- reintroduce code to not scan anon list if swap is full
- add code to scan anon list if page cache is very small already
- use lumpy reclaim more aggressively for smaller order > 1 allocations
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 01/24] vmscan: move isolate_lru_page() to vmscan.c
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 02/24] vmscan: Use an indexed array for LRU variables Rik van Riel
` (23 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, Nick Piggin,
Lee Schermerhorn
[-- Attachment #1: vmscan-move-isolate_lru_page-to-vmscanc.patch --]
[-- Type: text/plain, Size: 7400 bytes --]
From: Nick Piggin <npiggin@suse.de>
isolate_lru_page logically belongs to be in vmscan.c than migrate.c.
It is tough, because we don't need that function without memory migration
so there is a valid argument to have it in migrate.c. However a subsequent
patch needs to make use of it in the core mm, so we can happily move it
to vmscan.c.
Also, make the function a little more generic by not requiring that it
adds an isolated page to a given list. Callers can do that.
Note that we now have '__isolate_lru_page()', that does
something quite different, visible outside of vmscan.c
for use with memory controller. Methinks we need to
rationalize these names/purposes. --lts
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
---
V1 -> V2 [lts]:
+ fix botched merge -- add back "get_page_unless_zero()"
From: Nick Piggin <npiggin@suse.de>
To: Linux Memory Management <linux-mm@kvack.org>
Subject: [patch 1/4] mm: move and rework isolate_lru_page
Date: Mon, 12 Mar 2007 07:38:44 +0100 (CET)
include/linux/migrate.h | 3 ---
mm/internal.h | 2 ++
mm/mempolicy.c | 9 +++++++--
mm/migrate.c | 34 +++-------------------------------
mm/vmscan.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 57 insertions(+), 36 deletions(-)
Index: linux-2.6.26-rc5-mm2/include/linux/migrate.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/migrate.h 2008-06-10 12:33:42.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/migrate.h 2008-06-10 12:54:22.000000000 -0400
@@ -25,7 +25,6 @@ static inline int vma_migratable(struct
return 1;
}
-extern int isolate_lru_page(struct page *p, struct list_head *pagelist);
extern int putback_lru_pages(struct list_head *l);
extern int migrate_page(struct address_space *,
struct page *, struct page *);
@@ -42,8 +41,6 @@ extern int migrate_vmas(struct mm_struct
static inline int vma_migratable(struct vm_area_struct *vma)
{ return 0; }
-static inline int isolate_lru_page(struct page *p, struct list_head *list)
- { return -ENOSYS; }
static inline int putback_lru_pages(struct list_head *l) { return 0; }
static inline int migrate_pages(struct list_head *l, new_page_t x,
unsigned long private) { return -ENOSYS; }
Index: linux-2.6.26-rc5-mm2/mm/internal.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/internal.h 2008-06-10 12:33:42.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/internal.h 2008-06-10 12:54:22.000000000 -0400
@@ -39,6 +39,8 @@ static inline void __put_page(struct pag
atomic_dec(&page->_count);
}
+extern int isolate_lru_page(struct page *page);
+
extern void __free_pages_bootmem(struct page *page, unsigned int order);
/*
Index: linux-2.6.26-rc5-mm2/mm/migrate.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/migrate.c 2008-06-10 12:33:42.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/migrate.c 2008-06-10 12:54:22.000000000 -0400
@@ -37,36 +37,6 @@
#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
/*
- * Isolate one page from the LRU lists. If successful put it onto
- * the indicated list with elevated page count.
- *
- * Result:
- * -EBUSY: page not on LRU list
- * 0: page removed from LRU list and added to the specified list.
- */
-int isolate_lru_page(struct page *page, struct list_head *pagelist)
-{
- int ret = -EBUSY;
-
- if (PageLRU(page)) {
- struct zone *zone = page_zone(page);
-
- spin_lock_irq(&zone->lru_lock);
- if (PageLRU(page) && get_page_unless_zero(page)) {
- ret = 0;
- ClearPageLRU(page);
- if (PageActive(page))
- del_page_from_active_list(zone, page);
- else
- del_page_from_inactive_list(zone, page);
- list_add_tail(&page->lru, pagelist);
- }
- spin_unlock_irq(&zone->lru_lock);
- }
- return ret;
-}
-
-/*
* migrate_prep() needs to be called before we start compiling a list of pages
* to be migrated using isolate_lru_page().
*/
@@ -901,7 +871,9 @@ static int do_move_pages(struct mm_struc
!migrate_all)
goto put_and_set;
- err = isolate_lru_page(page, &pagelist);
+ err = isolate_lru_page(page);
+ if (!err)
+ list_add_tail(&page->lru, &pagelist);
put_and_set:
/*
* Either remove the duplicate refcount from
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 12:33:42.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 12:54:22.000000000 -0400
@@ -810,6 +810,51 @@ static unsigned long clear_active_flags(
return nr_active;
}
+/**
+ * isolate_lru_page - tries to isolate a page from its LRU list
+ * @page: page to isolate from its LRU list
+ *
+ * Isolates a @page from an LRU list, clears PageLRU and adjusts the
+ * vmstat statistic corresponding to whatever LRU list the page was on.
+ *
+ * Returns 0 if the page was removed from an LRU list.
+ * Returns -EBUSY if the page was not on an LRU list.
+ *
+ * The returned page will have PageLRU() cleared. If it was found on
+ * the active list, it will have PageActive set. That flag may need
+ * to be cleared by the caller before letting the page go.
+ *
+ * The vmstat statistic corresponding to the list on which the page was
+ * found will be decremented.
+ *
+ * Restrictions:
+ * (1) Must be called with an elevated refcount on the page. This is a
+ * fundamentnal difference from isolate_lru_pages (which is called
+ * without a stable reference).
+ * (2) the lru_lock must not be held.
+ * (3) interrupts must be enabled.
+ */
+int isolate_lru_page(struct page *page)
+{
+ int ret = -EBUSY;
+
+ if (PageLRU(page)) {
+ struct zone *zone = page_zone(page);
+
+ spin_lock_irq(&zone->lru_lock);
+ if (PageLRU(page) && get_page_unless_zero(page)) {
+ ret = 0;
+ ClearPageLRU(page);
+ if (PageActive(page))
+ del_page_from_active_list(zone, page);
+ else
+ del_page_from_inactive_list(zone, page);
+ }
+ spin_unlock_irq(&zone->lru_lock);
+ }
+ return ret;
+}
+
/*
* shrink_inactive_list() is a helper for shrink_zone(). It returns the number
* of reclaimed pages
Index: linux-2.6.26-rc5-mm2/mm/mempolicy.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mempolicy.c 2008-06-10 12:33:42.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mempolicy.c 2008-06-10 12:54:22.000000000 -0400
@@ -93,6 +93,8 @@
#include <asm/tlbflush.h>
#include <asm/uaccess.h>
+#include "internal.h"
+
/* Internal flags */
#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
@@ -758,8 +760,11 @@ static void migrate_page_add(struct page
/*
* Avoid migrating a page that is shared with others.
*/
- if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1)
- isolate_lru_page(page, pagelist);
+ if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
+ if (!isolate_lru_page(page)) {
+ list_add_tail(&page->lru, pagelist);
+ }
+ }
}
static struct page *new_node_page(struct page *page, unsigned long node, int **x)
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 02/24] vmscan: Use an indexed array for LRU variables
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 01/24] vmscan: move isolate_lru_page() to vmscan.c Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 03/24] swap: use an array for the LRU pagevecs Rik van Riel
` (22 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, Christoph Lameter
[-- Attachment #1: vmscan-use-an-indexed-array-for-lru-variables.patch --]
[-- Type: text/plain, Size: 22747 bytes --]
From: Christoph Lameter <clameter@sgi.com>
Currently we are defining explicit variables for the inactive
and active list. An indexed array can be more generic and avoid
repeating similar code in several places in the reclaim code.
We are saving a few bytes in terms of code size:
Before:
text data bss dec hex filename
4097753 573120 4092484 8763357 85b7dd vmlinux
After:
text data bss dec hex filename
4097729 573120 4092484 8763333 85b7c5 vmlinux
Having an easy way to add new lru lists may ease future work on
the reclaim code.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
include/linux/memcontrol.h | 17 +-----
include/linux/mm_inline.h | 49 ++++++++++++++----
include/linux/mmzone.h | 26 +++++++--
mm/memcontrol.c | 115 ++++++++++++++++---------------------------
mm/page_alloc.c | 9 +--
mm/swap.c | 2
mm/vmscan.c | 120 +++++++++++++++++++++------------------------
mm/vmstat.c | 3 -
8 files changed, 171 insertions(+), 170 deletions(-)
Index: linux-2.6.26-rc5-mm2/include/linux/mmzone.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mmzone.h 2008-06-10 10:25:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mmzone.h 2008-06-10 13:18:26.000000000 -0400
@@ -81,8 +81,9 @@ struct zone_padding {
enum zone_stat_item {
/* First 128 byte cacheline (assuming 64 bit words) */
NR_FREE_PAGES,
- NR_INACTIVE,
- NR_ACTIVE,
+ NR_LRU_BASE,
+ NR_INACTIVE = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
+ NR_ACTIVE, /* " " " " " */
NR_ANON_PAGES, /* Mapped anonymous pages */
NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
only modified from process context */
@@ -107,6 +108,19 @@ enum zone_stat_item {
#endif
NR_VM_ZONE_STAT_ITEMS };
+enum lru_list {
+ LRU_BASE,
+ LRU_INACTIVE=LRU_BASE, /* must match order of NR_[IN]ACTIVE */
+ LRU_ACTIVE, /* " " " " " */
+ NR_LRU_LISTS };
+
+#define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
+
+static inline int is_active_lru(enum lru_list l)
+{
+ return (l == LRU_ACTIVE);
+}
+
struct per_cpu_pages {
int count; /* number of pages in the list */
int high; /* high watermark, emptying needed */
@@ -251,10 +265,10 @@ struct zone {
/* Fields commonly accessed by the page reclaim scanner */
spinlock_t lru_lock;
- struct list_head active_list;
- struct list_head inactive_list;
- unsigned long nr_scan_active;
- unsigned long nr_scan_inactive;
+ struct {
+ struct list_head list;
+ unsigned long nr_scan;
+ } lru[NR_LRU_LISTS];
unsigned long pages_scanned; /* since last reclaim */
unsigned long flags; /* zone flags, see below */
Index: linux-2.6.26-rc5-mm2/include/linux/mm_inline.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mm_inline.h 2007-07-08 19:32:17.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mm_inline.h 2008-06-10 13:18:26.000000000 -0400
@@ -1,40 +1,67 @@
static inline void
+add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l)
+{
+ list_add(&page->lru, &zone->lru[l].list);
+ __inc_zone_state(zone, NR_LRU_BASE + l);
+}
+
+static inline void
+del_page_from_lru_list(struct zone *zone, struct page *page, enum lru_list l)
+{
+ list_del(&page->lru);
+ __dec_zone_state(zone, NR_LRU_BASE + l);
+}
+
+static inline void
add_page_to_active_list(struct zone *zone, struct page *page)
{
- list_add(&page->lru, &zone->active_list);
- __inc_zone_state(zone, NR_ACTIVE);
+ add_page_to_lru_list(zone, page, LRU_ACTIVE);
}
static inline void
add_page_to_inactive_list(struct zone *zone, struct page *page)
{
- list_add(&page->lru, &zone->inactive_list);
- __inc_zone_state(zone, NR_INACTIVE);
+ add_page_to_lru_list(zone, page, LRU_INACTIVE);
}
static inline void
del_page_from_active_list(struct zone *zone, struct page *page)
{
- list_del(&page->lru);
- __dec_zone_state(zone, NR_ACTIVE);
+ del_page_from_lru_list(zone, page, LRU_ACTIVE);
}
static inline void
del_page_from_inactive_list(struct zone *zone, struct page *page)
{
- list_del(&page->lru);
- __dec_zone_state(zone, NR_INACTIVE);
+ del_page_from_lru_list(zone, page, LRU_INACTIVE);
}
static inline void
del_page_from_lru(struct zone *zone, struct page *page)
{
+ enum lru_list l = LRU_INACTIVE;
+
list_del(&page->lru);
if (PageActive(page)) {
__ClearPageActive(page);
- __dec_zone_state(zone, NR_ACTIVE);
- } else {
- __dec_zone_state(zone, NR_INACTIVE);
+ l = LRU_ACTIVE;
}
+ __dec_zone_state(zone, NR_LRU_BASE + l);
}
+/**
+ * page_lru - which LRU list should a page be on?
+ * @page: the page to test
+ *
+ * Returns the LRU list a page should be on, as an index
+ * into the array of LRU lists.
+ */
+static inline enum lru_list page_lru(struct page *page)
+{
+ enum lru_list lru = LRU_BASE;
+
+ if (PageActive(page))
+ lru += LRU_ACTIVE;
+
+ return lru;
+}
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 10:46:24.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 13:18:26.000000000 -0400
@@ -3367,6 +3367,7 @@ static void __paginginit free_area_init_
for (j = 0; j < MAX_NR_ZONES; j++) {
struct zone *zone = pgdat->node_zones + j;
unsigned long size, realsize, memmap_pages;
+ enum lru_list l;
size = zone_spanned_pages_in_node(nid, j, zones_size);
realsize = size - zone_absent_pages_in_node(nid, j,
@@ -3418,10 +3419,10 @@ static void __paginginit free_area_init_
zone->prev_priority = DEF_PRIORITY;
zone_pcp_init(zone);
- INIT_LIST_HEAD(&zone->active_list);
- INIT_LIST_HEAD(&zone->inactive_list);
- zone->nr_scan_active = 0;
- zone->nr_scan_inactive = 0;
+ for_each_lru(l) {
+ INIT_LIST_HEAD(&zone->lru[l].list);
+ zone->lru[l].nr_scan = 0;
+ }
zap_zone_vm_stats(zone);
zone->flags = 0;
if (!size)
Index: linux-2.6.26-rc5-mm2/mm/swap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap.c 2008-06-10 10:25:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap.c 2008-06-10 13:18:26.000000000 -0400
@@ -117,7 +117,7 @@ static void pagevec_move_tail(struct pag
spin_lock(&zone->lru_lock);
}
if (PageLRU(page) && !PageActive(page)) {
- list_move_tail(&page->lru, &zone->inactive_list);
+ list_move_tail(&page->lru, &zone->lru[LRU_INACTIVE].list);
pgmoved++;
}
}
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 12:54:22.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 13:18:26.000000000 -0400
@@ -785,10 +785,10 @@ static unsigned long isolate_pages_globa
int active)
{
if (active)
- return isolate_lru_pages(nr, &z->active_list, dst,
+ return isolate_lru_pages(nr, &z->lru[LRU_ACTIVE].list, dst,
scanned, order, mode);
else
- return isolate_lru_pages(nr, &z->inactive_list, dst,
+ return isolate_lru_pages(nr, &z->lru[LRU_INACTIVE].list, dst,
scanned, order, mode);
}
@@ -939,10 +939,7 @@ static unsigned long shrink_inactive_lis
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);
list_del(&page->lru);
- if (PageActive(page))
- add_page_to_active_list(zone, page);
- else
- add_page_to_inactive_list(zone, page);
+ add_page_to_lru_list(zone, page, page_lru(page));
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
__pagevec_release(&pvec);
@@ -1110,8 +1107,8 @@ static void shrink_active_list(unsigned
int pgdeactivate = 0;
unsigned long pgscanned;
LIST_HEAD(l_hold); /* The pages which were snipped off */
- LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */
- LIST_HEAD(l_active); /* Pages to go onto the active_list */
+ LIST_HEAD(l_active);
+ LIST_HEAD(l_inactive);
struct page *page;
struct pagevec pvec;
int reclaim_mapped = 0;
@@ -1163,7 +1160,7 @@ static void shrink_active_list(unsigned
VM_BUG_ON(!PageActive(page));
ClearPageActive(page);
- list_move(&page->lru, &zone->inactive_list);
+ list_move(&page->lru, &zone->lru[LRU_INACTIVE].list);
mem_cgroup_move_lists(page, false);
pgmoved++;
if (!pagevec_add(&pvec, page)) {
@@ -1193,7 +1190,7 @@ static void shrink_active_list(unsigned
SetPageLRU(page);
VM_BUG_ON(!PageActive(page));
- list_move(&page->lru, &zone->active_list);
+ list_move(&page->lru, &zone->lru[LRU_ACTIVE].list);
mem_cgroup_move_lists(page, true);
pgmoved++;
if (!pagevec_add(&pvec, page)) {
@@ -1213,65 +1210,64 @@ static void shrink_active_list(unsigned
pagevec_release(&pvec);
}
+static unsigned long shrink_list(enum lru_list l, unsigned long nr_to_scan,
+ struct zone *zone, struct scan_control *sc, int priority)
+{
+ if (l == LRU_ACTIVE) {
+ shrink_active_list(nr_to_scan, zone, sc, priority);
+ return 0;
+ }
+ return shrink_inactive_list(nr_to_scan, zone, sc);
+}
+
/*
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
*/
static unsigned long shrink_zone(int priority, struct zone *zone,
struct scan_control *sc)
{
- unsigned long nr_active;
- unsigned long nr_inactive;
+ unsigned long nr[NR_LRU_LISTS];
unsigned long nr_to_scan;
unsigned long nr_reclaimed = 0;
+ enum lru_list l;
if (scan_global_lru(sc)) {
/*
* Add one to nr_to_scan just to make sure that the kernel
* will slowly sift through the active list.
*/
- zone->nr_scan_active +=
- (zone_page_state(zone, NR_ACTIVE) >> priority) + 1;
- nr_active = zone->nr_scan_active;
- zone->nr_scan_inactive +=
- (zone_page_state(zone, NR_INACTIVE) >> priority) + 1;
- nr_inactive = zone->nr_scan_inactive;
- if (nr_inactive >= sc->swap_cluster_max)
- zone->nr_scan_inactive = 0;
- else
- nr_inactive = 0;
-
- if (nr_active >= sc->swap_cluster_max)
- zone->nr_scan_active = 0;
- else
- nr_active = 0;
+ for_each_lru(l) {
+ zone->lru[l].nr_scan += (zone_page_state(zone,
+ NR_LRU_BASE + l) >> priority) + 1;
+ nr[l] = zone->lru[l].nr_scan;
+ if (nr[l] >= sc->swap_cluster_max)
+ zone->lru[l].nr_scan = 0;
+ else
+ nr[l] = 0;
+ }
} else {
/*
* This reclaim occurs not because zone memory shortage but
* because memory controller hits its limit.
* Then, don't modify zone reclaim related data.
*/
- nr_active = mem_cgroup_calc_reclaim_active(sc->mem_cgroup,
- zone, priority);
+ nr[LRU_ACTIVE] = mem_cgroup_calc_reclaim(sc->mem_cgroup,
+ zone, priority, LRU_ACTIVE);
- nr_inactive = mem_cgroup_calc_reclaim_inactive(sc->mem_cgroup,
- zone, priority);
+ nr[LRU_INACTIVE] = mem_cgroup_calc_reclaim(sc->mem_cgroup,
+ zone, priority, LRU_INACTIVE);
}
-
- while (nr_active || nr_inactive) {
- if (nr_active) {
- nr_to_scan = min(nr_active,
+ while (nr[LRU_ACTIVE] || nr[LRU_INACTIVE]) {
+ for_each_lru(l) {
+ if (nr[l]) {
+ nr_to_scan = min(nr[l],
(unsigned long)sc->swap_cluster_max);
- nr_active -= nr_to_scan;
- shrink_active_list(nr_to_scan, zone, sc, priority);
- }
+ nr[l] -= nr_to_scan;
- if (nr_inactive) {
- nr_to_scan = min(nr_inactive,
- (unsigned long)sc->swap_cluster_max);
- nr_inactive -= nr_to_scan;
- nr_reclaimed += shrink_inactive_list(nr_to_scan, zone,
- sc);
+ nr_reclaimed += shrink_list(l, nr_to_scan,
+ zone, sc, priority);
+ }
}
}
@@ -1788,6 +1784,7 @@ static unsigned long shrink_all_zones(un
{
struct zone *zone;
unsigned long nr_to_scan, ret = 0;
+ enum lru_list l;
for_each_zone(zone) {
@@ -1797,28 +1794,25 @@ static unsigned long shrink_all_zones(un
if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY)
continue;
- /* For pass = 0 we don't shrink the active list */
- if (pass > 0) {
- zone->nr_scan_active +=
- (zone_page_state(zone, NR_ACTIVE) >> prio) + 1;
- if (zone->nr_scan_active >= nr_pages || pass > 3) {
- zone->nr_scan_active = 0;
+ for_each_lru(l) {
+ /* For pass = 0 we don't shrink the active list */
+ if (pass == 0 && l == LRU_ACTIVE)
+ continue;
+
+ zone->lru[l].nr_scan +=
+ (zone_page_state(zone, NR_LRU_BASE + l)
+ >> prio) + 1;
+ if (zone->lru[l].nr_scan >= nr_pages || pass > 3) {
+ zone->lru[l].nr_scan = 0;
nr_to_scan = min(nr_pages,
- zone_page_state(zone, NR_ACTIVE));
- shrink_active_list(nr_to_scan, zone, sc, prio);
+ zone_page_state(zone,
+ NR_LRU_BASE + l));
+ ret += shrink_list(l, nr_to_scan, zone,
+ sc, prio);
+ if (ret >= nr_pages)
+ return ret;
}
}
-
- zone->nr_scan_inactive +=
- (zone_page_state(zone, NR_INACTIVE) >> prio) + 1;
- if (zone->nr_scan_inactive >= nr_pages || pass > 3) {
- zone->nr_scan_inactive = 0;
- nr_to_scan = min(nr_pages,
- zone_page_state(zone, NR_INACTIVE));
- ret += shrink_inactive_list(nr_to_scan, zone, sc);
- if (ret >= nr_pages)
- return ret;
- }
}
return ret;
Index: linux-2.6.26-rc5-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmstat.c 2008-06-10 10:46:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmstat.c 2008-06-10 13:18:26.000000000 -0400
@@ -679,7 +679,8 @@ static void zoneinfo_show_print(struct s
zone->pages_low,
zone->pages_high,
zone->pages_scanned,
- zone->nr_scan_active, zone->nr_scan_inactive,
+ zone->lru[LRU_ACTIVE].nr_scan,
+ zone->lru[LRU_INACTIVE].nr_scan,
zone->spanned_pages,
zone->present_pages);
Index: linux-2.6.26-rc5-mm2/include/linux/memcontrol.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/memcontrol.h 2008-06-10 10:46:29.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/memcontrol.h 2008-06-10 13:18:26.000000000 -0400
@@ -69,10 +69,8 @@ extern void mem_cgroup_note_reclaim_prio
extern void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
int priority);
-extern long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
- struct zone *zone, int priority);
-extern long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
- struct zone *zone, int priority);
+extern long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
+ int priority, enum lru_list lru);
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
static inline void page_reset_bad_cgroup(struct page *page)
@@ -159,14 +157,9 @@ static inline void mem_cgroup_record_rec
{
}
-static inline long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
- struct zone *zone, int priority)
-{
- return 0;
-}
-
-static inline long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
- struct zone *zone, int priority)
+static inline long mem_cgroup_calc_reclaim(struct mem_cgroup *mem,
+ struct zone *zone, int priority,
+ enum lru_list lru)
{
return 0;
}
Index: linux-2.6.26-rc5-mm2/mm/memcontrol.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memcontrol.c 2008-06-10 10:46:29.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memcontrol.c 2008-06-10 13:18:26.000000000 -0400
@@ -32,6 +32,7 @@
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
+#include <linux/mm_inline.h>
#include <asm/uaccess.h>
@@ -85,22 +86,13 @@ static s64 mem_cgroup_read_stat(struct m
/*
* per-zone information in memory controller.
*/
-
-enum mem_cgroup_zstat_index {
- MEM_CGROUP_ZSTAT_ACTIVE,
- MEM_CGROUP_ZSTAT_INACTIVE,
-
- NR_MEM_CGROUP_ZSTAT,
-};
-
struct mem_cgroup_per_zone {
/*
* spin_lock to protect the per cgroup LRU
*/
spinlock_t lru_lock;
- struct list_head active_list;
- struct list_head inactive_list;
- unsigned long count[NR_MEM_CGROUP_ZSTAT];
+ struct list_head lists[NR_LRU_LISTS];
+ unsigned long count[NR_LRU_LISTS];
};
/* Macro for accessing counter */
#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
@@ -227,7 +219,7 @@ page_cgroup_zoneinfo(struct page_cgroup
}
static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
- enum mem_cgroup_zstat_index idx)
+ enum lru_list idx)
{
int nid, zid;
struct mem_cgroup_per_zone *mz;
@@ -289,11 +281,9 @@ static void __mem_cgroup_remove_list(str
struct page_cgroup *pc)
{
int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
+ int lru = !!from;
- if (from)
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
- else
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
+ MEM_CGROUP_ZSTAT(mz, lru) -= 1;
mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
list_del(&pc->lru);
@@ -302,37 +292,35 @@ static void __mem_cgroup_remove_list(str
static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc)
{
- int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
+ int lru = LRU_INACTIVE;
+
+ if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
+ lru += LRU_ACTIVE;
+
+ MEM_CGROUP_ZSTAT(mz, lru) += 1;
+ list_add(&pc->lru, &mz->lists[lru]);
- if (!to) {
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
- list_add(&pc->lru, &mz->inactive_list);
- } else {
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
- list_add(&pc->lru, &mz->active_list);
- }
mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true);
}
static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
{
- int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
+ int lru = LRU_INACTIVE;
- if (from)
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
- else
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
+ if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
+ lru += LRU_ACTIVE;
- if (active) {
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
+ MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+
+ if (active)
pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
- list_move(&pc->lru, &mz->active_list);
- } else {
- MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
+ else
pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
- list_move(&pc->lru, &mz->inactive_list);
- }
+
+ lru = !!active;
+ MEM_CGROUP_ZSTAT(mz, lru) += 1;
+ list_move(&pc->lru, &mz->lists[lru]);
}
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
@@ -401,8 +389,8 @@ long mem_cgroup_reclaim_imbalance(struct
{
unsigned long active, inactive;
/* active and inactive are the number of pages. 'long' is ok.*/
- active = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_ACTIVE);
- inactive = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_INACTIVE);
+ active = mem_cgroup_get_all_zonestat(mem, LRU_ACTIVE);
+ inactive = mem_cgroup_get_all_zonestat(mem, LRU_INACTIVE);
return (long) (active / (inactive + 1));
}
@@ -433,28 +421,17 @@ void mem_cgroup_record_reclaim_priority(
* (see include/linux/mmzone.h)
*/
-long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
- struct zone *zone, int priority)
+long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
+ int priority, enum lru_list lru)
{
- long nr_active;
+ long nr_pages;
int nid = zone->zone_pgdat->node_id;
int zid = zone_idx(zone);
struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
- nr_active = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE);
- return (nr_active >> priority);
-}
-
-long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
- struct zone *zone, int priority)
-{
- long nr_inactive;
- int nid = zone->zone_pgdat->node_id;
- int zid = zone_idx(zone);
- struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ nr_pages = MEM_CGROUP_ZSTAT(mz, lru);
- nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE);
- return (nr_inactive >> priority);
+ return (nr_pages >> priority);
}
unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
@@ -473,14 +450,11 @@ unsigned long mem_cgroup_isolate_pages(u
int nid = z->zone_pgdat->node_id;
int zid = zone_idx(z);
struct mem_cgroup_per_zone *mz;
+ int lru = !!active;
BUG_ON(!mem_cont);
mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
- if (active)
- src = &mz->active_list;
- else
- src = &mz->inactive_list;
-
+ src = &mz->lists[lru];
spin_lock(&mz->lru_lock);
scan = 0;
@@ -798,7 +772,7 @@ int mem_cgroup_shrink_usage(struct mm_st
#define FORCE_UNCHARGE_BATCH (128)
static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
struct mem_cgroup_per_zone *mz,
- int active)
+ enum lru_list lru)
{
struct page_cgroup *pc;
struct page *page;
@@ -806,10 +780,7 @@ static void mem_cgroup_force_empty_list(
unsigned long flags;
struct list_head *list;
- if (active)
- list = &mz->active_list;
- else
- list = &mz->inactive_list;
+ list = &mz->lists[lru];
spin_lock_irqsave(&mz->lru_lock, flags);
while (!list_empty(list)) {
@@ -857,11 +828,10 @@ static int mem_cgroup_force_empty(struct
for_each_node_state(node, N_POSSIBLE)
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
struct mem_cgroup_per_zone *mz;
+ enum lru_list l;
mz = mem_cgroup_zoneinfo(mem, node, zid);
- /* drop all page_cgroup in active_list */
- mem_cgroup_force_empty_list(mem, mz, 1);
- /* drop all page_cgroup in inactive_list */
- mem_cgroup_force_empty_list(mem, mz, 0);
+ for_each_lru(l)
+ mem_cgroup_force_empty_list(mem, mz, l);
}
}
ret = 0;
@@ -948,9 +918,9 @@ static int mem_control_stat_show(struct
unsigned long active, inactive;
inactive = mem_cgroup_get_all_zonestat(mem_cont,
- MEM_CGROUP_ZSTAT_INACTIVE);
+ LRU_INACTIVE);
active = mem_cgroup_get_all_zonestat(mem_cont,
- MEM_CGROUP_ZSTAT_ACTIVE);
+ LRU_ACTIVE);
cb->fill(cb, "active", (active) * PAGE_SIZE);
cb->fill(cb, "inactive", (inactive) * PAGE_SIZE);
}
@@ -995,6 +965,7 @@ static int alloc_mem_cgroup_per_zone_inf
{
struct mem_cgroup_per_node *pn;
struct mem_cgroup_per_zone *mz;
+ enum lru_list l;
int zone, tmp = node;
/*
* This routine is called against possible nodes.
@@ -1015,9 +986,9 @@ static int alloc_mem_cgroup_per_zone_inf
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
mz = &pn->zoneinfo[zone];
- INIT_LIST_HEAD(&mz->active_list);
- INIT_LIST_HEAD(&mz->inactive_list);
spin_lock_init(&mz->lru_lock);
+ for_each_lru(l)
+ INIT_LIST_HEAD(&mz->lists[l]);
}
return 0;
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 03/24] swap: use an array for the LRU pagevecs
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 01/24] vmscan: move isolate_lru_page() to vmscan.c Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 02/24] vmscan: Use an indexed array for LRU variables Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 04/24] vmscan: free swap space on swap-in/activation Rik van Riel
` (21 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-use-an-array-for-the-lru-pagevecs.patch --]
[-- Type: text/plain, Size: 7733 bytes --]
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Turn the pagevecs into an array just like the LRUs. This significantly
cleans up the source code and reduces the size of the kernel by about
13kB after all the LRU lists have been created further down in the split
VM patch series.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
include/linux/pagevec.h | 13 ++++++-
include/linux/swap.h | 18 +++++++++-
mm/migrate.c | 11 ------
mm/swap.c | 79 ++++++++++++++++--------------------------------
4 files changed, 55 insertions(+), 66 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/swap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap.c 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap.c 2008-06-10 13:18:58.000000000 -0400
@@ -34,8 +34,7 @@
/* How many pages do we try to swap or page in/out together? */
int page_cluster;
-static DEFINE_PER_CPU(struct pagevec, lru_add_pvecs) = { 0, };
-static DEFINE_PER_CPU(struct pagevec, lru_add_active_pvecs) = { 0, };
+static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs) = { {0,}, };
static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs) = { 0, };
/*
@@ -186,28 +185,29 @@ void mark_page_accessed(struct page *pag
EXPORT_SYMBOL(mark_page_accessed);
-/**
- * lru_cache_add: add a page to the page lists
- * @page: the page to add
- */
-void lru_cache_add(struct page *page)
+void __lru_cache_add(struct page *page, enum lru_list lru)
{
- struct pagevec *pvec = &get_cpu_var(lru_add_pvecs);
+ struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
page_cache_get(page);
if (!pagevec_add(pvec, page))
- __pagevec_lru_add(pvec);
+ ____pagevec_lru_add(pvec, lru);
put_cpu_var(lru_add_pvecs);
}
-void lru_cache_add_active(struct page *page)
+/**
+ * lru_cache_add_lru - add a page to a page list
+ * @page: the page to be added to the LRU.
+ * @lru: the LRU list to which the page is added.
+ */
+void lru_cache_add_lru(struct page *page, enum lru_list lru)
{
- struct pagevec *pvec = &get_cpu_var(lru_add_active_pvecs);
+ if (PageActive(page)) {
+ ClearPageActive(page);
+ }
- page_cache_get(page);
- if (!pagevec_add(pvec, page))
- __pagevec_lru_add_active(pvec);
- put_cpu_var(lru_add_active_pvecs);
+ VM_BUG_ON(PageLRU(page) || PageActive(page));
+ __lru_cache_add(page, lru);
}
/*
@@ -217,15 +217,15 @@ void lru_cache_add_active(struct page *p
*/
static void drain_cpu_pagevecs(int cpu)
{
+ struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu);
struct pagevec *pvec;
+ int lru;
- pvec = &per_cpu(lru_add_pvecs, cpu);
- if (pagevec_count(pvec))
- __pagevec_lru_add(pvec);
-
- pvec = &per_cpu(lru_add_active_pvecs, cpu);
- if (pagevec_count(pvec))
- __pagevec_lru_add_active(pvec);
+ for_each_lru(lru) {
+ pvec = &pvecs[lru - LRU_BASE];
+ if (pagevec_count(pvec))
+ ____pagevec_lru_add(pvec, lru);
+ }
pvec = &per_cpu(lru_rotate_pvecs, cpu);
if (pagevec_count(pvec)) {
@@ -379,7 +379,7 @@ void __pagevec_release_nonlru(struct pag
* Add the passed pages to the LRU, then drop the caller's refcount
* on them. Reinitialises the caller's pagevec.
*/
-void __pagevec_lru_add(struct pagevec *pvec)
+void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
{
int i;
struct zone *zone = NULL;
@@ -396,7 +396,9 @@ void __pagevec_lru_add(struct pagevec *p
}
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);
- add_page_to_inactive_list(zone, page);
+ if (is_active_lru(lru))
+ SetPageActive(page);
+ add_page_to_lru_list(zone, page, lru);
}
if (zone)
spin_unlock_irq(&zone->lru_lock);
@@ -404,34 +406,7 @@ void __pagevec_lru_add(struct pagevec *p
pagevec_reinit(pvec);
}
-EXPORT_SYMBOL(__pagevec_lru_add);
-
-void __pagevec_lru_add_active(struct pagevec *pvec)
-{
- int i;
- struct zone *zone = NULL;
-
- for (i = 0; i < pagevec_count(pvec); i++) {
- struct page *page = pvec->pages[i];
- struct zone *pagezone = page_zone(page);
-
- if (pagezone != zone) {
- if (zone)
- spin_unlock_irq(&zone->lru_lock);
- zone = pagezone;
- spin_lock_irq(&zone->lru_lock);
- }
- VM_BUG_ON(PageLRU(page));
- SetPageLRU(page);
- VM_BUG_ON(PageActive(page));
- SetPageActive(page);
- add_page_to_active_list(zone, page);
- }
- if (zone)
- spin_unlock_irq(&zone->lru_lock);
- release_pages(pvec->pages, pvec->nr, pvec->cold);
- pagevec_reinit(pvec);
-}
+EXPORT_SYMBOL(____pagevec_lru_add);
/*
* Try to drop buffers from the pages in a pagevec
Index: linux-2.6.26-rc5-mm2/include/linux/pagevec.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/pagevec.h 2007-07-08 19:32:17.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/pagevec.h 2008-06-10 13:18:58.000000000 -0400
@@ -23,8 +23,7 @@ struct pagevec {
void __pagevec_release(struct pagevec *pvec);
void __pagevec_release_nonlru(struct pagevec *pvec);
void __pagevec_free(struct pagevec *pvec);
-void __pagevec_lru_add(struct pagevec *pvec);
-void __pagevec_lru_add_active(struct pagevec *pvec);
+void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru);
void pagevec_strip(struct pagevec *pvec);
unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
pgoff_t start, unsigned nr_pages);
@@ -81,6 +80,16 @@ static inline void pagevec_free(struct p
__pagevec_free(pvec);
}
+static inline void __pagevec_lru_add(struct pagevec *pvec)
+{
+ ____pagevec_lru_add(pvec, LRU_INACTIVE);
+}
+
+static inline void __pagevec_lru_add_active(struct pagevec *pvec)
+{
+ ____pagevec_lru_add(pvec, LRU_ACTIVE);
+}
+
static inline void pagevec_lru_add(struct pagevec *pvec)
{
if (pagevec_count(pvec))
Index: linux-2.6.26-rc5-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/swap.h 2008-06-10 10:25:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/swap.h 2008-06-10 13:18:58.000000000 -0400
@@ -171,8 +171,8 @@ extern unsigned int nr_free_pagecache_pa
/* linux/mm/swap.c */
-extern void lru_cache_add(struct page *);
-extern void lru_cache_add_active(struct page *);
+extern void __lru_cache_add(struct page *, enum lru_list lru);
+extern void lru_cache_add_lru(struct page *, enum lru_list lru);
extern void activate_page(struct page *);
extern void mark_page_accessed(struct page *);
extern void lru_add_drain(void);
@@ -180,6 +180,20 @@ extern int lru_add_drain_all(void);
extern void rotate_reclaimable_page(struct page *page);
extern void swap_setup(void);
+/**
+ * lru_cache_add: add a page to the page lists
+ * @page: the page to add
+ */
+static inline void lru_cache_add(struct page *page)
+{
+ __lru_cache_add(page, LRU_INACTIVE);
+}
+
+static inline void lru_cache_add_active(struct page *page)
+{
+ __lru_cache_add(page, LRU_ACTIVE);
+}
+
/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask);
Index: linux-2.6.26-rc5-mm2/mm/migrate.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/migrate.c 2008-06-10 12:54:22.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/migrate.c 2008-06-10 13:18:58.000000000 -0400
@@ -55,16 +55,7 @@ int migrate_prep(void)
static inline void move_to_lru(struct page *page)
{
- if (PageActive(page)) {
- /*
- * lru_cache_add_active checks that
- * the PG_active bit is off.
- */
- ClearPageActive(page);
- lru_cache_add_active(page);
- } else {
- lru_cache_add(page);
- }
+ lru_cache_add_lru(page, page_lru(page));
put_page(page);
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 04/24] vmscan: free swap space on swap-in/activation
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (2 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 03/24] swap: use an array for the LRU pagevecs Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 05/24] define page_file_cache() function Rik van Riel
` (20 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, MinChan Kim,
Lee Schermerhorn
[-- Attachment #1: vmscan-free-swap-space-on-swap-in-activation.patch --]
[-- Type: text/plain, Size: 6689 bytes --]
From: Rik van Riel <riel@redhat.com>
If vm_swap_full() (swap space more than 50% full), the system
will free swap space at swapin time. With this patch, the system
will also free the swap space in the pageout code, when we decide
that the page is not a candidate for swapout (and just wasting
swap space).
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: MinChan Kim <minchan.kim@gmail.com>
---
include/linux/pagevec.h | 1 +
include/linux/swap.h | 6 ++++++
mm/swap.c | 24 ++++++++++++++++++++++++
mm/swapfile.c | 25 ++++++++++++++++++++++---
mm/vmscan.c | 7 +++++++
5 files changed, 60 insertions(+), 3 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 13:34:07.000000000 -0400
@@ -613,6 +613,9 @@ free_it:
continue;
activate_locked:
+ /* Not a candidate for swapping, so reclaim swap space. */
+ if (PageSwapCache(page) && vm_swap_full())
+ remove_exclusive_swap_page_ref(page);
SetPageActive(page);
pgactivate++;
keep_locked:
@@ -1197,6 +1200,8 @@ static void shrink_active_list(unsigned
__mod_zone_page_state(zone, NR_ACTIVE, pgmoved);
pgmoved = 0;
spin_unlock_irq(&zone->lru_lock);
+ if (vm_swap_full())
+ pagevec_swap_free(&pvec);
__pagevec_release(&pvec);
spin_lock_irq(&zone->lru_lock);
}
@@ -1206,6 +1211,8 @@ static void shrink_active_list(unsigned
__count_zone_vm_events(PGREFILL, zone, pgscanned);
__count_vm_events(PGDEACTIVATE, pgdeactivate);
spin_unlock_irq(&zone->lru_lock);
+ if (vm_swap_full())
+ pagevec_swap_free(&pvec);
pagevec_release(&pvec);
}
Index: linux-2.6.26-rc5-mm2/mm/swap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap.c 2008-06-10 13:18:58.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap.c 2008-06-10 13:34:07.000000000 -0400
@@ -427,6 +427,30 @@ void pagevec_strip(struct pagevec *pvec)
}
/**
+ * pagevec_swap_free - try to free swap space from the pages in a pagevec
+ * @pvec: pagevec with swapcache pages to free the swap space of
+ *
+ * The caller needs to hold an extra reference to each page and
+ * not hold the page lock on the pages. This function uses a
+ * trylock on the page lock so it may not always free the swap
+ * space associated with a page.
+ */
+void pagevec_swap_free(struct pagevec *pvec)
+{
+ int i;
+
+ for (i = 0; i < pagevec_count(pvec); i++) {
+ struct page *page = pvec->pages[i];
+
+ if (PageSwapCache(page) && !TestSetPageLocked(page)) {
+ if (PageSwapCache(page))
+ remove_exclusive_swap_page_ref(page);
+ unlock_page(page);
+ }
+ }
+}
+
+/**
* pagevec_lookup - gang pagecache lookup
* @pvec: Where the resulting pages are placed
* @mapping: The address_space to search
Index: linux-2.6.26-rc5-mm2/include/linux/pagevec.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/pagevec.h 2008-06-10 13:18:58.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/pagevec.h 2008-06-10 13:34:07.000000000 -0400
@@ -25,6 +25,7 @@ void __pagevec_release_nonlru(struct pag
void __pagevec_free(struct pagevec *pvec);
void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru);
void pagevec_strip(struct pagevec *pvec);
+void pagevec_swap_free(struct pagevec *pvec);
unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
pgoff_t start, unsigned nr_pages);
unsigned pagevec_lookup_tag(struct pagevec *pvec,
Index: linux-2.6.26-rc5-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/swap.h 2008-06-10 13:18:58.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/swap.h 2008-06-10 13:34:07.000000000 -0400
@@ -266,6 +266,7 @@ extern sector_t swapdev_block(int, pgoff
extern struct swap_info_struct *get_swap_info_struct(unsigned);
extern int can_share_swap_page(struct page *);
extern int remove_exclusive_swap_page(struct page *);
+extern int remove_exclusive_swap_page_ref(struct page *);
struct backing_dev_info;
extern spinlock_t swap_lock;
@@ -356,6 +357,11 @@ static inline int remove_exclusive_swap_
return 0;
}
+static inline int remove_exclusive_swap_page_ref(struct page *page)
+{
+ return 0;
+}
+
static inline swp_entry_t get_swap_page(void)
{
swp_entry_t entry;
Index: linux-2.6.26-rc5-mm2/mm/swapfile.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swapfile.c 2008-06-10 10:25:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swapfile.c 2008-06-10 13:34:07.000000000 -0400
@@ -343,7 +343,7 @@ int can_share_swap_page(struct page *pag
* Work out if there are any other processes sharing this
* swap cache page. Free it if you can. Return success.
*/
-int remove_exclusive_swap_page(struct page *page)
+static int remove_exclusive_swap_page_count(struct page *page, int count)
{
int retval;
struct swap_info_struct * p;
@@ -356,7 +356,7 @@ int remove_exclusive_swap_page(struct pa
return 0;
if (PageWriteback(page))
return 0;
- if (page_count(page) != 2) /* 2: us + cache */
+ if (page_count(page) != count) /* us + cache + ptes */
return 0;
entry.val = page_private(page);
@@ -369,7 +369,7 @@ int remove_exclusive_swap_page(struct pa
if (p->swap_map[swp_offset(entry)] == 1) {
/* Recheck the page count with the swapcache lock held.. */
write_lock_irq(&swapper_space.tree_lock);
- if ((page_count(page) == 2) && !PageWriteback(page)) {
+ if ((page_count(page) == count) && !PageWriteback(page)) {
__delete_from_swap_cache(page);
SetPageDirty(page);
retval = 1;
@@ -387,6 +387,25 @@ int remove_exclusive_swap_page(struct pa
}
/*
+ * Most of the time the page should have two references: one for the
+ * process and one for the swap cache.
+ */
+int remove_exclusive_swap_page(struct page *page)
+{
+ return remove_exclusive_swap_page_count(page, 2);
+}
+
+/*
+ * The pageout code holds an extra reference to the page. That raises
+ * the reference count to test for to 2 for a page that is only in the
+ * swap cache plus 1 for each process that maps the page.
+ */
+int remove_exclusive_swap_page_ref(struct page *page)
+{
+ return remove_exclusive_swap_page_count(page, 2 + page_mapcount(page));
+}
+
+/*
* Free the swap entry like above, but also try to
* free the page cache entry if it is the last user.
*/
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 05/24] define page_file_cache() function
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (3 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 04/24] vmscan: free swap space on swap-in/activation Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 06/24] vmscan: split LRU lists into anon & file sets Rik van Riel
` (19 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, MinChan Kim
[-- Attachment #1: vmscan-define-page_file_cache-function.patch --]
[-- Type: text/plain, Size: 7809 bytes --]
From: Rik van Riel <riel@redhat.com>
Define page_file_cache() function to answer the question:
is page backed by a file?
Originally part of Rik van Riel's split-lru patch. Extracted
to make available for other, independent reclaim patches.
Moved inline function to linux/mm_inline.h where it will
be needed by subsequent "split LRU" and "noreclaim" patches.
Unfortunately this needs to use a page flag, since the
PG_swapbacked state needs to be preserved all the way
to the point where the page is last removed from the
LRU. Trying to derive the status from other info in
the page resulted in wrong VM statistics in earlier
split VM patchsets.
The total number of page flags in use on a 32 bit
machine after this patch is 19.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: MinChan Kim <minchan.kim@gmail.com>
---
include/linux/mm_inline.h | 27 +++++++++++++++++++++++++++
include/linux/page-flags.h | 2 ++
mm/memory.c | 3 +++
mm/migrate.c | 2 ++
mm/page_alloc.c | 4 ++++
mm/shmem.c | 1 +
mm/swap_state.c | 3 +++
7 files changed, 42 insertions(+)
Index: linux-2.6.26-rc5-mm2/include/linux/mm_inline.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mm_inline.h 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mm_inline.h 2008-06-10 13:34:48.000000000 -0400
@@ -1,3 +1,28 @@
+#ifndef LINUX_MM_INLINE_H
+#define LINUX_MM_INLINE_H
+
+/**
+ * page_is_file_cache - should the page be on a file LRU or anon LRU?
+ * @page: the page to test
+ *
+ * Returns !0 if @page is page cache page backed by a regular filesystem,
+ * or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed.
+ * Used by functions that manipulate the LRU lists, to sort a page
+ * onto the right LRU list.
+ *
+ * We would like to get this info without a page flag, but the state
+ * needs to survive until the page is last deleted from the LRU, which
+ * could be as far down as __page_cache_release.
+ */
+static inline int page_is_file_cache(struct page *page)
+{
+ if (PageSwapBacked(page))
+ return 0;
+
+ /* The page is page cache backed by a normal filesystem. */
+ return 1;
+}
+
static inline void
add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l)
{
@@ -65,3 +90,5 @@ static inline enum lru_list page_lru(str
return lru;
}
+
+#endif
Index: linux-2.6.26-rc5-mm2/mm/shmem.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/shmem.c 2008-06-10 10:46:29.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/shmem.c 2008-06-10 13:34:48.000000000 -0400
@@ -1387,6 +1387,7 @@ repeat:
goto failed;
}
+ SetPageSwapBacked(filepage);
spin_lock(&info->lock);
entry = shmem_swp_alloc(info, idx, sgp);
if (IS_ERR(entry))
Index: linux-2.6.26-rc5-mm2/include/linux/page-flags.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/page-flags.h 2008-06-10 10:46:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/page-flags.h 2008-06-10 13:34:48.000000000 -0400
@@ -93,6 +93,7 @@ enum pageflags {
PG_mappedtodisk, /* Has blocks allocated on-disk */
PG_reclaim, /* To be reclaimed asap */
PG_buddy, /* Page is free, on buddy lists */
+ PG_swapbacked, /* Page is backed by RAM/swap */
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PG_uncached, /* Page has been mapped as uncached */
#endif
@@ -176,6 +177,7 @@ PAGEFLAG(SavePinned, savepinned); /* X
PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
__SETPAGEFLAG(Private, private)
+PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
__PAGEFLAG(SlobPage, slob_page)
__PAGEFLAG(SlobFree, slob_free)
Index: linux-2.6.26-rc5-mm2/mm/memory.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memory.c 2008-06-10 10:46:25.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memory.c 2008-06-10 13:34:48.000000000 -0400
@@ -1804,6 +1804,7 @@ gotten:
ptep_clear_flush(vma, address, page_table);
set_pte_at(mm, address, page_table, entry);
update_mmu_cache(vma, address, entry);
+ SetPageSwapBacked(new_page);
lru_cache_add_active(new_page);
page_add_new_anon_rmap(new_page, vma, address);
@@ -2272,6 +2273,7 @@ static int do_anonymous_page(struct mm_s
if (!pte_none(*page_table))
goto release;
inc_mm_counter(mm, anon_rss);
+ SetPageSwapBacked(page);
lru_cache_add_active(page);
page_add_new_anon_rmap(page, vma, address);
set_pte_at(mm, address, page_table, entry);
@@ -2413,6 +2415,7 @@ static int __do_fault(struct mm_struct *
set_pte_at(mm, address, page_table, entry);
if (anon) {
inc_mm_counter(mm, anon_rss);
+ SetPageSwapBacked(page);
lru_cache_add_active(page);
page_add_new_anon_rmap(page, vma, address);
} else {
Index: linux-2.6.26-rc5-mm2/mm/swap_state.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap_state.c 2008-06-10 10:46:29.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap_state.c 2008-06-10 13:34:48.000000000 -0400
@@ -74,6 +74,7 @@ int add_to_swap_cache(struct page *page,
BUG_ON(!PageLocked(page));
BUG_ON(PageSwapCache(page));
BUG_ON(PagePrivate(page));
+ BUG_ON(!PageSwapBacked(page));
error = radix_tree_preload(gfp_mask);
if (!error) {
write_lock_irq(&swapper_space.tree_lock);
@@ -296,6 +297,7 @@ struct page *read_swap_cache_async(swp_e
* May fail (-ENOMEM) if radix-tree node allocation failed.
*/
SetPageLocked(new_page);
+ SetPageSwapBacked(new_page);
err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
if (!err) {
/*
@@ -305,6 +307,7 @@ struct page *read_swap_cache_async(swp_e
swap_readpage(NULL, new_page);
return new_page;
}
+ ClearPageSwapBacked(new_page);
ClearPageLocked(new_page);
swap_free(entry);
} while (err != -ENOMEM);
Index: linux-2.6.26-rc5-mm2/mm/migrate.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/migrate.c 2008-06-10 13:18:58.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/migrate.c 2008-06-10 13:34:48.000000000 -0400
@@ -564,6 +564,8 @@ static int move_to_new_page(struct page
/* Prepare mapping for the new page.*/
newpage->index = page->index;
newpage->mapping = page->mapping;
+ if (PageSwapBacked(page))
+ SetPageSwapBacked(newpage);
mapping = page_mapping(page);
if (!mapping)
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 13:34:48.000000000 -0400
@@ -246,6 +246,7 @@ static void bad_page(struct page *page)
1 << PG_slab |
1 << PG_swapcache |
1 << PG_writeback |
+ 1 << PG_swapbacked |
1 << PG_buddy );
set_page_count(page, 0);
reset_page_mapcount(page);
@@ -477,6 +478,8 @@ static inline int free_pages_check(struc
bad_page(page);
if (PageDirty(page))
__ClearPageDirty(page);
+ if (PageSwapBacked(page))
+ __ClearPageSwapBacked(page);
/*
* For now, we report if PG_reserved was found set, but do not
* clear it, and do not free the page. But we shall soon need
@@ -627,6 +630,7 @@ static int prep_new_page(struct page *pa
1 << PG_swapcache |
1 << PG_writeback |
1 << PG_reserved |
+ 1 << PG_swapbacked |
1 << PG_buddy ))))
bad_page(page);
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 06/24] vmscan: split LRU lists into anon & file sets
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (4 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 05/24] define page_file_cache() function Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-13 0:39 ` Hiroshi Shimamoto
2008-06-11 18:42 ` [PATCH -mm 07/24] vmscan: second chance replacement for anonymous pages Rik van Riel
` (18 subsequent siblings)
24 siblings, 1 reply; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, Lee Schermerhorn
[-- Attachment #1: vmscan-split-lru-lists-into-anon-file-sets.patch --]
[-- Type: text/plain, Size: 59193 bytes --]
From: Rik van Riel <riel@redhat.com>
Split the LRU lists in two, one set for pages that are backed by
real file systems ("file") and one for pages that are backed by
memory and swap ("anon"). The latter includes tmpfs.
The advantage of doing this is that the VM will not have to scan
over lots of anonymous pages (which we generally do not want to
swap out), just to find the page cache pages that it should evict.
This patch has the infrastructure and a basic policy to balance
how much we scan the anon lists and how much we scan the file
lists. The big policy changes are in separate patches.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
---
drivers/base/node.c | 56 +++---
fs/cifs/file.c | 4
fs/nfs/dir.c | 2
fs/ntfs/file.c | 4
fs/proc/proc_misc.c | 77 ++++----
fs/ramfs/file-nommu.c | 4
include/linux/memcontrol.h | 2
include/linux/mm_inline.h | 50 ++++-
include/linux/mmzone.h | 47 ++++-
include/linux/pagevec.h | 29 ++-
include/linux/swap.h | 20 +-
include/linux/vmstat.h | 10 +
mm/filemap.c | 9
mm/memcontrol.c | 73 ++++---
mm/memory.c | 6
mm/page-writeback.c | 8
mm/page_alloc.c | 25 +-
mm/readahead.c | 2
mm/swap.c | 14 +
mm/swap_state.c | 2
mm/vmscan.c | 420 +++++++++++++++++++++++----------------------
mm/vmstat.c | 14 -
22 files changed, 519 insertions(+), 359 deletions(-)
Index: linux-2.6.26-rc5-mm2/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/proc/proc_misc.c 2008-06-10 10:46:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/proc/proc_misc.c 2008-06-10 13:35:22.000000000 -0400
@@ -137,6 +137,8 @@ static int meminfo_read_proc(char *page,
unsigned long allowed;
struct vmalloc_info vmi;
long cached;
+ unsigned long pages[NR_LRU_LISTS];
+ int lru;
/*
* display in kilobytes.
@@ -155,48 +157,59 @@ static int meminfo_read_proc(char *page,
get_vmalloc_info(&vmi);
+ for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
+ pages[lru] = global_page_state(lru);
+
/*
* Tagged format, for easy grepping and expansion.
*/
len = sprintf(page,
- "MemTotal: %8lu kB\n"
- "MemFree: %8lu kB\n"
- "Buffers: %8lu kB\n"
- "Cached: %8lu kB\n"
- "SwapCached: %8lu kB\n"
- "Active: %8lu kB\n"
- "Inactive: %8lu kB\n"
+ "MemTotal: %8lu kB\n"
+ "MemFree: %8lu kB\n"
+ "Buffers: %8lu kB\n"
+ "Cached: %8lu kB\n"
+ "SwapCached: %8lu kB\n"
+ "Active: %8lu kB\n"
+ "Inactive: %8lu kB\n"
+ "Active(anon): %8lu kB\n"
+ "Inactive(anon): %8lu kB\n"
+ "Active(file): %8lu kB\n"
+ "Inactive(file): %8lu kB\n"
#ifdef CONFIG_HIGHMEM
- "HighTotal: %8lu kB\n"
- "HighFree: %8lu kB\n"
- "LowTotal: %8lu kB\n"
- "LowFree: %8lu kB\n"
-#endif
- "SwapTotal: %8lu kB\n"
- "SwapFree: %8lu kB\n"
- "Dirty: %8lu kB\n"
- "Writeback: %8lu kB\n"
- "AnonPages: %8lu kB\n"
- "Mapped: %8lu kB\n"
- "Slab: %8lu kB\n"
- "SReclaimable: %8lu kB\n"
- "SUnreclaim: %8lu kB\n"
- "PageTables: %8lu kB\n"
- "NFS_Unstable: %8lu kB\n"
- "Bounce: %8lu kB\n"
- "WritebackTmp: %8lu kB\n"
- "CommitLimit: %8lu kB\n"
- "Committed_AS: %8lu kB\n"
- "VmallocTotal: %8lu kB\n"
- "VmallocUsed: %8lu kB\n"
- "VmallocChunk: %8lu kB\n",
+ "HighTotal: %8lu kB\n"
+ "HighFree: %8lu kB\n"
+ "LowTotal: %8lu kB\n"
+ "LowFree: %8lu kB\n"
+#endif
+ "SwapTotal: %8lu kB\n"
+ "SwapFree: %8lu kB\n"
+ "Dirty: %8lu kB\n"
+ "Writeback: %8lu kB\n"
+ "AnonPages: %8lu kB\n"
+ "Mapped: %8lu kB\n"
+ "Slab: %8lu kB\n"
+ "SReclaimable: %8lu kB\n"
+ "SUnreclaim: %8lu kB\n"
+ "PageTables: %8lu kB\n"
+ "NFS_Unstable: %8lu kB\n"
+ "Bounce: %8lu kB\n"
+ "WritebackTmp: %8lu kB\n"
+ "CommitLimit: %8lu kB\n"
+ "Committed_AS: %8lu kB\n"
+ "VmallocTotal: %8lu kB\n"
+ "VmallocUsed: %8lu kB\n"
+ "VmallocChunk: %8lu kB\n",
K(i.totalram),
K(i.freeram),
K(i.bufferram),
K(cached),
K(total_swapcache_pages),
- K(global_page_state(NR_ACTIVE)),
- K(global_page_state(NR_INACTIVE)),
+ K(pages[LRU_ACTIVE_ANON] + pages[LRU_ACTIVE_FILE]),
+ K(pages[LRU_INACTIVE_ANON] + pages[LRU_INACTIVE_FILE]),
+ K(pages[LRU_ACTIVE_ANON]),
+ K(pages[LRU_INACTIVE_ANON]),
+ K(pages[LRU_ACTIVE_FILE]),
+ K(pages[LRU_INACTIVE_FILE]),
#ifdef CONFIG_HIGHMEM
K(i.totalhigh),
K(i.freehigh),
Index: linux-2.6.26-rc5-mm2/fs/cifs/file.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/cifs/file.c 2008-06-10 10:46:19.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/cifs/file.c 2008-06-10 13:35:22.000000000 -0400
@@ -1775,7 +1775,7 @@ static void cifs_copy_cache_pages(struct
SetPageUptodate(page);
unlock_page(page);
if (!pagevec_add(plru_pvec, page))
- __pagevec_lru_add(plru_pvec);
+ __pagevec_lru_add_file(plru_pvec);
data += PAGE_CACHE_SIZE;
}
return;
@@ -1909,7 +1909,7 @@ static int cifs_readpages(struct file *f
bytes_read = 0;
}
- pagevec_lru_add(&lru_pvec);
+ pagevec_lru_add_file(&lru_pvec);
/* need to free smb_read_data buf before exit */
if (smb_read_data) {
Index: linux-2.6.26-rc5-mm2/fs/ntfs/file.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/ntfs/file.c 2008-06-10 10:24:46.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/ntfs/file.c 2008-06-10 13:35:22.000000000 -0400
@@ -439,7 +439,7 @@ static inline int __ntfs_grab_cache_page
pages[nr] = *cached_page;
page_cache_get(*cached_page);
if (unlikely(!pagevec_add(lru_pvec, *cached_page)))
- __pagevec_lru_add(lru_pvec);
+ __pagevec_lru_add_file(lru_pvec);
*cached_page = NULL;
}
index++;
@@ -2084,7 +2084,7 @@ err_out:
OSYNC_METADATA|OSYNC_DATA);
}
}
- pagevec_lru_add(&lru_pvec);
+ pagevec_lru_add_file(&lru_pvec);
ntfs_debug("Done. Returning %s (written 0x%lx, status %li).",
written ? "written" : "status", (unsigned long)written,
(long)status);
Index: linux-2.6.26-rc5-mm2/fs/nfs/dir.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/nfs/dir.c 2008-06-10 10:25:06.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/nfs/dir.c 2008-06-10 13:35:22.000000000 -0400
@@ -1524,7 +1524,7 @@ static int nfs_symlink(struct inode *dir
if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0,
GFP_KERNEL)) {
pagevec_add(&lru_pvec, page);
- pagevec_lru_add(&lru_pvec);
+ pagevec_lru_add_file(&lru_pvec);
SetPageUptodate(page);
unlock_page(page);
} else
Index: linux-2.6.26-rc5-mm2/fs/ramfs/file-nommu.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/ramfs/file-nommu.c 2008-06-10 10:24:29.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/ramfs/file-nommu.c 2008-06-10 13:35:22.000000000 -0400
@@ -111,12 +111,12 @@ static int ramfs_nommu_expand_for_mappin
goto add_error;
if (!pagevec_add(&lru_pvec, page))
- __pagevec_lru_add(&lru_pvec);
+ __pagevec_lru_add_file(&lru_pvec);
unlock_page(page);
}
- pagevec_lru_add(&lru_pvec);
+ pagevec_lru_add_file(&lru_pvec);
return 0;
fsize_exceeded:
Index: linux-2.6.26-rc5-mm2/drivers/base/node.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/drivers/base/node.c 2008-06-10 10:25:05.000000000 -0400
+++ linux-2.6.26-rc5-mm2/drivers/base/node.c 2008-06-10 13:35:22.000000000 -0400
@@ -58,34 +58,44 @@ static ssize_t node_read_meminfo(struct
si_meminfo_node(&i, nid);
n = sprintf(buf, "\n"
- "Node %d MemTotal: %8lu kB\n"
- "Node %d MemFree: %8lu kB\n"
- "Node %d MemUsed: %8lu kB\n"
- "Node %d Active: %8lu kB\n"
- "Node %d Inactive: %8lu kB\n"
+ "Node %d MemTotal: %8lu kB\n"
+ "Node %d MemFree: %8lu kB\n"
+ "Node %d MemUsed: %8lu kB\n"
+ "Node %d Active: %8lu kB\n"
+ "Node %d Inactive: %8lu kB\n"
+ "Node %d Active(anon): %8lu kB\n"
+ "Node %d Inactive(anon): %8lu kB\n"
+ "Node %d Active(file): %8lu kB\n"
+ "Node %d Inactive(file): %8lu kB\n"
#ifdef CONFIG_HIGHMEM
- "Node %d HighTotal: %8lu kB\n"
- "Node %d HighFree: %8lu kB\n"
- "Node %d LowTotal: %8lu kB\n"
- "Node %d LowFree: %8lu kB\n"
+ "Node %d HighTotal: %8lu kB\n"
+ "Node %d HighFree: %8lu kB\n"
+ "Node %d LowTotal: %8lu kB\n"
+ "Node %d LowFree: %8lu kB\n"
#endif
- "Node %d Dirty: %8lu kB\n"
- "Node %d Writeback: %8lu kB\n"
- "Node %d FilePages: %8lu kB\n"
- "Node %d Mapped: %8lu kB\n"
- "Node %d AnonPages: %8lu kB\n"
- "Node %d PageTables: %8lu kB\n"
- "Node %d NFS_Unstable: %8lu kB\n"
- "Node %d Bounce: %8lu kB\n"
- "Node %d WritebackTmp: %8lu kB\n"
- "Node %d Slab: %8lu kB\n"
- "Node %d SReclaimable: %8lu kB\n"
- "Node %d SUnreclaim: %8lu kB\n",
+ "Node %d Dirty: %8lu kB\n"
+ "Node %d Writeback: %8lu kB\n"
+ "Node %d FilePages: %8lu kB\n"
+ "Node %d Mapped: %8lu kB\n"
+ "Node %d AnonPages: %8lu kB\n"
+ "Node %d PageTables: %8lu kB\n"
+ "Node %d NFS_Unstable: %8lu kB\n"
+ "Node %d Bounce: %8lu kB\n"
+ "Node %d WritebackTmp: %8lu kB\n"
+ "Node %d Slab: %8lu kB\n"
+ "Node %d SReclaimable: %8lu kB\n"
+ "Node %d SUnreclaim: %8lu kB\n",
nid, K(i.totalram),
nid, K(i.freeram),
nid, K(i.totalram - i.freeram),
- nid, node_page_state(nid, NR_ACTIVE),
- nid, node_page_state(nid, NR_INACTIVE),
+ nid, node_page_state(nid, NR_ACTIVE_ANON) +
+ node_page_state(nid, NR_ACTIVE_FILE),
+ nid, node_page_state(nid, NR_INACTIVE_ANON) +
+ node_page_state(nid, NR_INACTIVE_FILE),
+ nid, node_page_state(nid, NR_ACTIVE_ANON),
+ nid, node_page_state(nid, NR_INACTIVE_ANON),
+ nid, node_page_state(nid, NR_ACTIVE_FILE),
+ nid, node_page_state(nid, NR_INACTIVE_FILE),
#ifdef CONFIG_HIGHMEM
nid, K(i.totalhigh),
nid, K(i.freehigh),
Index: linux-2.6.26-rc5-mm2/mm/memory.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memory.c 2008-06-10 13:34:48.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memory.c 2008-06-10 13:35:23.000000000 -0400
@@ -1805,7 +1805,7 @@ gotten:
set_pte_at(mm, address, page_table, entry);
update_mmu_cache(vma, address, entry);
SetPageSwapBacked(new_page);
- lru_cache_add_active(new_page);
+ lru_cache_add_active_anon(new_page);
page_add_new_anon_rmap(new_page, vma, address);
/* Free the old page.. */
@@ -2274,7 +2274,7 @@ static int do_anonymous_page(struct mm_s
goto release;
inc_mm_counter(mm, anon_rss);
SetPageSwapBacked(page);
- lru_cache_add_active(page);
+ lru_cache_add_active_anon(page);
page_add_new_anon_rmap(page, vma, address);
set_pte_at(mm, address, page_table, entry);
@@ -2416,7 +2416,7 @@ static int __do_fault(struct mm_struct *
if (anon) {
inc_mm_counter(mm, anon_rss);
SetPageSwapBacked(page);
- lru_cache_add_active(page);
+ lru_cache_add_active_anon(page);
page_add_new_anon_rmap(page, vma, address);
} else {
inc_mm_counter(mm, file_rss);
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 13:34:48.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 13:35:23.000000000 -0400
@@ -1834,10 +1834,13 @@ void show_free_areas(void)
}
}
- printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu\n"
+ printk("Active_anon:%lu active_file:%lu inactive_anon%lu\n"
+ " inactive_file:%lu dirty:%lu writeback:%lu unstable:%lu\n"
" free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
- global_page_state(NR_ACTIVE),
- global_page_state(NR_INACTIVE),
+ global_page_state(NR_ACTIVE_ANON),
+ global_page_state(NR_ACTIVE_FILE),
+ global_page_state(NR_INACTIVE_ANON),
+ global_page_state(NR_INACTIVE_FILE),
global_page_state(NR_FILE_DIRTY),
global_page_state(NR_WRITEBACK),
global_page_state(NR_UNSTABLE_NFS),
@@ -1860,8 +1863,10 @@ void show_free_areas(void)
" min:%lukB"
" low:%lukB"
" high:%lukB"
- " active:%lukB"
- " inactive:%lukB"
+ " active_anon:%lukB"
+ " inactive_anon:%lukB"
+ " active_file:%lukB"
+ " inactive_file:%lukB"
" present:%lukB"
" pages_scanned:%lu"
" all_unreclaimable? %s"
@@ -1871,8 +1876,10 @@ void show_free_areas(void)
K(zone->pages_min),
K(zone->pages_low),
K(zone->pages_high),
- K(zone_page_state(zone, NR_ACTIVE)),
- K(zone_page_state(zone, NR_INACTIVE)),
+ K(zone_page_state(zone, NR_ACTIVE_ANON)),
+ K(zone_page_state(zone, NR_INACTIVE_ANON)),
+ K(zone_page_state(zone, NR_ACTIVE_FILE)),
+ K(zone_page_state(zone, NR_INACTIVE_FILE)),
K(zone->present_pages),
zone->pages_scanned,
(zone_is_all_unreclaimable(zone) ? "yes" : "no")
@@ -3427,6 +3434,10 @@ static void __paginginit free_area_init_
INIT_LIST_HEAD(&zone->lru[l].list);
zone->lru[l].nr_scan = 0;
}
+ zone->recent_rotated[0] = 0;
+ zone->recent_rotated[1] = 0;
+ zone->recent_scanned[0] = 0;
+ zone->recent_scanned[1] = 0;
zap_zone_vm_stats(zone);
zone->flags = 0;
if (!size)
Index: linux-2.6.26-rc5-mm2/mm/swap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap.c 2008-06-10 13:34:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap.c 2008-06-10 13:35:23.000000000 -0400
@@ -116,7 +116,8 @@ static void pagevec_move_tail(struct pag
spin_lock(&zone->lru_lock);
}
if (PageLRU(page) && !PageActive(page)) {
- list_move_tail(&page->lru, &zone->lru[LRU_INACTIVE].list);
+ int lru = page_is_file_cache(page);
+ list_move_tail(&page->lru, &zone->lru[lru].list);
pgmoved++;
}
}
@@ -157,11 +158,18 @@ void activate_page(struct page *page)
spin_lock_irq(&zone->lru_lock);
if (PageLRU(page) && !PageActive(page)) {
- del_page_from_inactive_list(zone, page);
+ int file = page_is_file_cache(page);
+ int lru = LRU_BASE + file;
+ del_page_from_lru_list(zone, page, lru);
+
SetPageActive(page);
- add_page_to_active_list(zone, page);
+ lru += LRU_ACTIVE;
+ add_page_to_lru_list(zone, page, lru);
__count_vm_event(PGACTIVATE);
mem_cgroup_move_lists(page, true);
+
+ zone->recent_rotated[!!file]++;
+ zone->recent_scanned[!!file]++;
}
spin_unlock_irq(&zone->lru_lock);
}
Index: linux-2.6.26-rc5-mm2/mm/readahead.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/readahead.c 2008-06-10 10:25:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/readahead.c 2008-06-10 13:35:23.000000000 -0400
@@ -229,7 +229,7 @@ int do_page_cache_readahead(struct addre
*/
unsigned long max_sane_readahead(unsigned long nr)
{
- return min(nr, (node_page_state(numa_node_id(), NR_INACTIVE)
+ return min(nr, (node_page_state(numa_node_id(), NR_INACTIVE_FILE)
+ node_page_state(numa_node_id(), NR_FREE_PAGES)) / 2);
}
Index: linux-2.6.26-rc5-mm2/mm/filemap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/filemap.c 2008-06-10 10:46:29.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/filemap.c 2008-06-10 13:35:23.000000000 -0400
@@ -33,6 +33,7 @@
#include <linux/cpuset.h>
#include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
#include <linux/memcontrol.h>
+#include <linux/mm_inline.h> /* for page_is_file_cache() */
#include "internal.h"
/*
@@ -488,8 +489,12 @@ int add_to_page_cache_lru(struct page *p
pgoff_t offset, gfp_t gfp_mask)
{
int ret = add_to_page_cache(page, mapping, offset, gfp_mask);
- if (ret == 0)
- lru_cache_add(page);
+ if (ret == 0) {
+ if (page_is_file_cache(page))
+ lru_cache_add_file(page);
+ else
+ lru_cache_add_active_anon(page);
+ }
return ret;
}
Index: linux-2.6.26-rc5-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmstat.c 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmstat.c 2008-06-10 13:35:23.000000000 -0400
@@ -602,8 +602,10 @@ const struct seq_operations pagetypeinfo
static const char * const vmstat_text[] = {
/* Zoned VM counters */
"nr_free_pages",
- "nr_inactive",
- "nr_active",
+ "nr_inactive_anon",
+ "nr_active_anon",
+ "nr_inactive_file",
+ "nr_active_file",
"nr_anon_pages",
"nr_mapped",
"nr_file_pages",
@@ -671,7 +673,7 @@ static void zoneinfo_show_print(struct s
"\n min %lu"
"\n low %lu"
"\n high %lu"
- "\n scanned %lu (a: %lu i: %lu)"
+ "\n scanned %lu (aa: %lu ia: %lu af: %lu if: %lu)"
"\n spanned %lu"
"\n present %lu",
zone_page_state(zone, NR_FREE_PAGES),
@@ -679,8 +681,10 @@ static void zoneinfo_show_print(struct s
zone->pages_low,
zone->pages_high,
zone->pages_scanned,
- zone->lru[LRU_ACTIVE].nr_scan,
- zone->lru[LRU_INACTIVE].nr_scan,
+ zone->lru[LRU_ACTIVE_ANON].nr_scan,
+ zone->lru[LRU_INACTIVE_ANON].nr_scan,
+ zone->lru[LRU_ACTIVE_FILE].nr_scan,
+ zone->lru[LRU_INACTIVE_FILE].nr_scan,
zone->spanned_pages,
zone->present_pages);
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 13:34:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 13:35:23.000000000 -0400
@@ -78,7 +78,7 @@ struct scan_control {
unsigned long (*isolate_pages)(unsigned long nr, struct list_head *dst,
unsigned long *scanned, int order, int mode,
struct zone *z, struct mem_cgroup *mem_cont,
- int active);
+ int active, int file);
};
#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
@@ -646,7 +646,7 @@ keep:
*
* returns 0 on success, -ve errno on failure.
*/
-int __isolate_lru_page(struct page *page, int mode)
+int __isolate_lru_page(struct page *page, int mode, int file)
{
int ret = -EINVAL;
@@ -662,6 +662,9 @@ int __isolate_lru_page(struct page *page
if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode))
return ret;
+ if (mode != ISOLATE_BOTH && (!page_is_file_cache(page) != !file))
+ return ret;
+
ret = -EBUSY;
if (likely(get_page_unless_zero(page))) {
/*
@@ -692,12 +695,13 @@ int __isolate_lru_page(struct page *page
* @scanned: The number of pages that were scanned.
* @order: The caller's attempted allocation order
* @mode: One of the LRU isolation modes
+ * @file: True [1] if isolating file [!anon] pages
*
* returns how many pages were moved onto *@dst.
*/
static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
struct list_head *src, struct list_head *dst,
- unsigned long *scanned, int order, int mode)
+ unsigned long *scanned, int order, int mode, int file)
{
unsigned long nr_taken = 0;
unsigned long scan;
@@ -714,7 +718,7 @@ static unsigned long isolate_lru_pages(u
VM_BUG_ON(!PageLRU(page));
- switch (__isolate_lru_page(page, mode)) {
+ switch (__isolate_lru_page(page, mode, file)) {
case 0:
list_move(&page->lru, dst);
nr_taken++;
@@ -757,10 +761,11 @@ static unsigned long isolate_lru_pages(u
break;
cursor_page = pfn_to_page(pfn);
+
/* Check that we have not crossed a zone boundary. */
if (unlikely(page_zone_id(cursor_page) != zone_id))
continue;
- switch (__isolate_lru_page(cursor_page, mode)) {
+ switch (__isolate_lru_page(cursor_page, mode, file)) {
case 0:
list_move(&cursor_page->lru, dst);
nr_taken++;
@@ -785,30 +790,37 @@ static unsigned long isolate_pages_globa
unsigned long *scanned, int order,
int mode, struct zone *z,
struct mem_cgroup *mem_cont,
- int active)
+ int active, int file)
{
+ int lru = LRU_BASE;
if (active)
- return isolate_lru_pages(nr, &z->lru[LRU_ACTIVE].list, dst,
- scanned, order, mode);
- else
- return isolate_lru_pages(nr, &z->lru[LRU_INACTIVE].list, dst,
- scanned, order, mode);
+ lru += LRU_ACTIVE;
+ if (file)
+ lru += LRU_FILE;
+ return isolate_lru_pages(nr, &z->lru[lru].list, dst, scanned, order,
+ mode, !!file);
}
/*
* clear_active_flags() is a helper for shrink_active_list(), clearing
* any active bits from the pages in the list.
*/
-static unsigned long clear_active_flags(struct list_head *page_list)
+static unsigned long clear_active_flags(struct list_head *page_list,
+ unsigned int *count)
{
int nr_active = 0;
+ int lru;
struct page *page;
- list_for_each_entry(page, page_list, lru)
+ list_for_each_entry(page, page_list, lru) {
+ lru = page_is_file_cache(page);
if (PageActive(page)) {
+ lru += LRU_ACTIVE;
ClearPageActive(page);
nr_active++;
}
+ count[lru]++;
+ }
return nr_active;
}
@@ -846,12 +858,12 @@ int isolate_lru_page(struct page *page)
spin_lock_irq(&zone->lru_lock);
if (PageLRU(page) && get_page_unless_zero(page)) {
+ int lru = LRU_BASE;
ret = 0;
ClearPageLRU(page);
- if (PageActive(page))
- del_page_from_active_list(zone, page);
- else
- del_page_from_inactive_list(zone, page);
+
+ lru += page_is_file_cache(page) + !!PageActive(page);
+ del_page_from_lru_list(zone, page, lru);
}
spin_unlock_irq(&zone->lru_lock);
}
@@ -863,7 +875,7 @@ int isolate_lru_page(struct page *page)
* of reclaimed pages
*/
static unsigned long shrink_inactive_list(unsigned long max_scan,
- struct zone *zone, struct scan_control *sc)
+ struct zone *zone, struct scan_control *sc, int file)
{
LIST_HEAD(page_list);
struct pagevec pvec;
@@ -880,20 +892,32 @@ static unsigned long shrink_inactive_lis
unsigned long nr_scan;
unsigned long nr_freed;
unsigned long nr_active;
+ unsigned int count[NR_LRU_LISTS] = { 0, };
+ int mode = (sc->order > PAGE_ALLOC_COSTLY_ORDER) ?
+ ISOLATE_BOTH : ISOLATE_INACTIVE;
nr_taken = sc->isolate_pages(sc->swap_cluster_max,
- &page_list, &nr_scan, sc->order,
- (sc->order > PAGE_ALLOC_COSTLY_ORDER)?
- ISOLATE_BOTH : ISOLATE_INACTIVE,
- zone, sc->mem_cgroup, 0);
- nr_active = clear_active_flags(&page_list);
+ &page_list, &nr_scan, sc->order, mode,
+ zone, sc->mem_cgroup, 0, file);
+ nr_active = clear_active_flags(&page_list, count);
__count_vm_events(PGDEACTIVATE, nr_active);
- __mod_zone_page_state(zone, NR_ACTIVE, -nr_active);
- __mod_zone_page_state(zone, NR_INACTIVE,
- -(nr_taken - nr_active));
- if (scan_global_lru(sc))
+ __mod_zone_page_state(zone, NR_ACTIVE_FILE,
+ -count[LRU_ACTIVE_FILE]);
+ __mod_zone_page_state(zone, NR_INACTIVE_FILE,
+ -count[LRU_INACTIVE_FILE]);
+ __mod_zone_page_state(zone, NR_ACTIVE_ANON,
+ -count[LRU_ACTIVE_ANON]);
+ __mod_zone_page_state(zone, NR_INACTIVE_ANON,
+ -count[LRU_INACTIVE_ANON]);
+
+ if (scan_global_lru(sc)) {
zone->pages_scanned += nr_scan;
+ zone->recent_scanned[0] += count[LRU_INACTIVE_ANON];
+ zone->recent_scanned[0] += count[LRU_ACTIVE_ANON];
+ zone->recent_scanned[1] += count[LRU_INACTIVE_FILE];
+ zone->recent_scanned[1] += count[LRU_ACTIVE_FILE];
+ }
spin_unlock_irq(&zone->lru_lock);
nr_scanned += nr_scan;
@@ -913,7 +937,7 @@ static unsigned long shrink_inactive_lis
* The attempt at page out may have made some
* of the pages active, mark them inactive again.
*/
- nr_active = clear_active_flags(&page_list);
+ nr_active = clear_active_flags(&page_list, count);
count_vm_events(PGDEACTIVATE, nr_active);
nr_freed += shrink_page_list(&page_list, sc,
@@ -943,6 +967,10 @@ static unsigned long shrink_inactive_lis
SetPageLRU(page);
list_del(&page->lru);
add_page_to_lru_list(zone, page, page_lru(page));
+ if (PageActive(page) && scan_global_lru(sc)) {
+ int file = !!page_is_file_cache(page);
+ zone->recent_rotated[file]++;
+ }
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
__pagevec_release(&pvec);
@@ -973,115 +1001,7 @@ static inline void note_zone_scanning_pr
static inline int zone_is_near_oom(struct zone *zone)
{
- return zone->pages_scanned >= (zone_page_state(zone, NR_ACTIVE)
- + zone_page_state(zone, NR_INACTIVE))*3;
-}
-
-/*
- * Determine we should try to reclaim mapped pages.
- * This is called only when sc->mem_cgroup is NULL.
- */
-static int calc_reclaim_mapped(struct scan_control *sc, struct zone *zone,
- int priority)
-{
- long mapped_ratio;
- long distress;
- long swap_tendency;
- long imbalance;
- int reclaim_mapped = 0;
- int prev_priority;
-
- if (scan_global_lru(sc) && zone_is_near_oom(zone))
- return 1;
- /*
- * `distress' is a measure of how much trouble we're having
- * reclaiming pages. 0 -> no problems. 100 -> great trouble.
- */
- if (scan_global_lru(sc))
- prev_priority = zone->prev_priority;
- else
- prev_priority = mem_cgroup_get_reclaim_priority(sc->mem_cgroup);
-
- distress = 100 >> min(prev_priority, priority);
-
- /*
- * The point of this algorithm is to decide when to start
- * reclaiming mapped memory instead of just pagecache. Work out
- * how much memory
- * is mapped.
- */
- if (scan_global_lru(sc))
- mapped_ratio = ((global_page_state(NR_FILE_MAPPED) +
- global_page_state(NR_ANON_PAGES)) * 100) /
- vm_total_pages;
- else
- mapped_ratio = mem_cgroup_calc_mapped_ratio(sc->mem_cgroup);
-
- /*
- * Now decide how much we really want to unmap some pages. The
- * mapped ratio is downgraded - just because there's a lot of
- * mapped memory doesn't necessarily mean that page reclaim
- * isn't succeeding.
- *
- * The distress ratio is important - we don't want to start
- * going oom.
- *
- * A 100% value of vm_swappiness overrides this algorithm
- * altogether.
- */
- swap_tendency = mapped_ratio / 2 + distress + sc->swappiness;
-
- /*
- * If there's huge imbalance between active and inactive
- * (think active 100 times larger than inactive) we should
- * become more permissive, or the system will take too much
- * cpu before it start swapping during memory pressure.
- * Distress is about avoiding early-oom, this is about
- * making swappiness graceful despite setting it to low
- * values.
- *
- * Avoid div by zero with nr_inactive+1, and max resulting
- * value is vm_total_pages.
- */
- if (scan_global_lru(sc)) {
- imbalance = zone_page_state(zone, NR_ACTIVE);
- imbalance /= zone_page_state(zone, NR_INACTIVE) + 1;
- } else
- imbalance = mem_cgroup_reclaim_imbalance(sc->mem_cgroup);
-
- /*
- * Reduce the effect of imbalance if swappiness is low,
- * this means for a swappiness very low, the imbalance
- * must be much higher than 100 for this logic to make
- * the difference.
- *
- * Max temporary value is vm_total_pages*100.
- */
- imbalance *= (vm_swappiness + 1);
- imbalance /= 100;
-
- /*
- * If not much of the ram is mapped, makes the imbalance
- * less relevant, it's high priority we refill the inactive
- * list with mapped pages only in presence of high ratio of
- * mapped pages.
- *
- * Max temporary value is vm_total_pages*100.
- */
- imbalance *= mapped_ratio;
- imbalance /= 100;
-
- /* apply imbalance feedback to swap_tendency */
- swap_tendency += imbalance;
-
- /*
- * Now use this metric to decide whether to start moving mapped
- * memory onto the inactive list.
- */
- if (swap_tendency >= 100)
- reclaim_mapped = 1;
-
- return reclaim_mapped;
+ return zone->pages_scanned >= (zone_lru_pages(zone) * 3);
}
/*
@@ -1104,7 +1024,7 @@ static int calc_reclaim_mapped(struct sc
static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
- struct scan_control *sc, int priority)
+ struct scan_control *sc, int priority, int file)
{
unsigned long pgmoved;
int pgdeactivate = 0;
@@ -1114,46 +1034,45 @@ static void shrink_active_list(unsigned
LIST_HEAD(l_inactive);
struct page *page;
struct pagevec pvec;
- int reclaim_mapped = 0;
-
- if (sc->may_swap)
- reclaim_mapped = calc_reclaim_mapped(sc, zone, priority);
+ enum lru_list lru;
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order,
ISOLATE_ACTIVE, zone,
- sc->mem_cgroup, 1);
+ sc->mem_cgroup, 1, file);
/*
* zone->pages_scanned is used for detect zone's oom
* mem_cgroup remembers nr_scan by itself.
*/
- if (scan_global_lru(sc))
+ if (scan_global_lru(sc)) {
zone->pages_scanned += pgscanned;
+ zone->recent_scanned[!!file] += pgmoved;
+ }
- __mod_zone_page_state(zone, NR_ACTIVE, -pgmoved);
+ if (file)
+ __mod_zone_page_state(zone, NR_ACTIVE_FILE, -pgmoved);
+ else
+ __mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved);
spin_unlock_irq(&zone->lru_lock);
while (!list_empty(&l_hold)) {
cond_resched();
page = lru_to_page(&l_hold);
list_del(&page->lru);
- if (page_mapped(page)) {
- if (!reclaim_mapped ||
- (total_swap_pages == 0 && PageAnon(page)) ||
- page_referenced(page, 0, sc->mem_cgroup)) {
- list_add(&page->lru, &l_active);
- continue;
- }
- } else if (TestClearPageReferenced(page)) {
+ if (page_referenced(page, 0, sc->mem_cgroup))
list_add(&page->lru, &l_active);
- continue;
- }
- list_add(&page->lru, &l_inactive);
+ else
+ list_add(&page->lru, &l_inactive);
}
+ /*
+ * Now put the pages back on the appropriate [file or anon] inactive
+ * and active lists.
+ */
pagevec_init(&pvec, 1);
pgmoved = 0;
+ lru = LRU_BASE + file * LRU_FILE;
spin_lock_irq(&zone->lru_lock);
while (!list_empty(&l_inactive)) {
page = lru_to_page(&l_inactive);
@@ -1163,11 +1082,11 @@ static void shrink_active_list(unsigned
VM_BUG_ON(!PageActive(page));
ClearPageActive(page);
- list_move(&page->lru, &zone->lru[LRU_INACTIVE].list);
+ list_move(&page->lru, &zone->lru[lru].list);
mem_cgroup_move_lists(page, false);
pgmoved++;
if (!pagevec_add(&pvec, page)) {
- __mod_zone_page_state(zone, NR_INACTIVE, pgmoved);
+ __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
spin_unlock_irq(&zone->lru_lock);
pgdeactivate += pgmoved;
pgmoved = 0;
@@ -1177,7 +1096,7 @@ static void shrink_active_list(unsigned
spin_lock_irq(&zone->lru_lock);
}
}
- __mod_zone_page_state(zone, NR_INACTIVE, pgmoved);
+ __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
pgdeactivate += pgmoved;
if (buffer_heads_over_limit) {
spin_unlock_irq(&zone->lru_lock);
@@ -1186,6 +1105,7 @@ static void shrink_active_list(unsigned
}
pgmoved = 0;
+ lru = LRU_ACTIVE + file * LRU_FILE;
while (!list_empty(&l_active)) {
page = lru_to_page(&l_active);
prefetchw_prev_lru_page(page, &l_active, flags);
@@ -1193,11 +1113,11 @@ static void shrink_active_list(unsigned
SetPageLRU(page);
VM_BUG_ON(!PageActive(page));
- list_move(&page->lru, &zone->lru[LRU_ACTIVE].list);
+ list_move(&page->lru, &zone->lru[lru].list);
mem_cgroup_move_lists(page, true);
pgmoved++;
if (!pagevec_add(&pvec, page)) {
- __mod_zone_page_state(zone, NR_ACTIVE, pgmoved);
+ __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
pgmoved = 0;
spin_unlock_irq(&zone->lru_lock);
if (vm_swap_full())
@@ -1206,7 +1126,8 @@ static void shrink_active_list(unsigned
spin_lock_irq(&zone->lru_lock);
}
}
- __mod_zone_page_state(zone, NR_ACTIVE, pgmoved);
+ __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
+ zone->recent_rotated[!!file] += pgmoved;
__count_zone_vm_events(PGREFILL, zone, pgscanned);
__count_vm_events(PGDEACTIVATE, pgdeactivate);
@@ -1217,16 +1138,103 @@ static void shrink_active_list(unsigned
pagevec_release(&pvec);
}
-static unsigned long shrink_list(enum lru_list l, unsigned long nr_to_scan,
+static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
struct zone *zone, struct scan_control *sc, int priority)
{
- if (l == LRU_ACTIVE) {
- shrink_active_list(nr_to_scan, zone, sc, priority);
+ int file = is_file_lru(lru);
+
+ if (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE) {
+ shrink_active_list(nr_to_scan, zone, sc, priority, file);
return 0;
}
- return shrink_inactive_list(nr_to_scan, zone, sc);
+ return shrink_inactive_list(nr_to_scan, zone, sc, file);
+}
+
+/*
+ * Determine how aggressively the anon and file LRU lists should be
+ * scanned. The relative value of each set of LRU lists is determined
+ * by looking at the fraction of the pages scanned we did rotate back
+ * onto the active list instead of evict.
+ *
+ * percent[0] specifies how much pressure to put on ram/swap backed
+ * memory, while percent[1] determines pressure on the file LRUs.
+ */
+static void get_scan_ratio(struct zone *zone, struct scan_control * sc,
+ unsigned long *percent)
+{
+ unsigned long anon, file, free;
+ unsigned long anon_prio, file_prio;
+ unsigned long ap, fp;
+
+ anon = zone_page_state(zone, NR_ACTIVE_ANON) +
+ zone_page_state(zone, NR_INACTIVE_ANON);
+ file = zone_page_state(zone, NR_ACTIVE_FILE) +
+ zone_page_state(zone, NR_INACTIVE_FILE);
+ free = zone_page_state(zone, NR_FREE_PAGES);
+
+ /* If we have no swap space, do not bother scanning anon pages. */
+ if (nr_swap_pages <= 0) {
+ percent[0] = 0;
+ percent[1] = 100;
+ return;
+ }
+
+ /* If we have very few page cache pages, force-scan anon pages. */
+ if (unlikely(file + free <= zone->pages_high)) {
+ percent[0] = 100;
+ percent[1] = 0;
+ return;
+ }
+
+ /*
+ * OK, so we have swap space and a fair amount of page cache
+ * pages. We use the recently rotated / recently scanned
+ * ratios to determine how valuable each cache is.
+ *
+ * Because workloads change over time (and to avoid overflow)
+ * we keep these statistics as a floating average, which ends
+ * up weighing recent references more than old ones.
+ *
+ * anon in [0], file in [1]
+ */
+ if (unlikely(zone->recent_scanned[0] > anon / 4)) {
+ spin_lock_irq(&zone->lru_lock);
+ zone->recent_scanned[0] /= 2;
+ zone->recent_rotated[0] /= 2;
+ spin_unlock_irq(&zone->lru_lock);
+ }
+
+ if (unlikely(zone->recent_scanned[1] > file / 4)) {
+ spin_lock_irq(&zone->lru_lock);
+ zone->recent_scanned[1] /= 2;
+ zone->recent_rotated[1] /= 2;
+ spin_unlock_irq(&zone->lru_lock);
+ }
+
+ /*
+ * With swappiness at 100, anonymous and file have the same priority.
+ * This scanning priority is essentially the inverse of IO cost.
+ */
+ anon_prio = sc->swappiness;
+ file_prio = 200 - sc->swappiness;
+
+ /*
+ * anon recent_rotated[0]
+ * %anon = 100 * ----------- / ----------------- * IO cost
+ * anon + file rotate_sum
+ */
+ ap = (anon_prio + 1) * (zone->recent_scanned[0] + 1);
+ ap /= zone->recent_rotated[0] + 1;
+
+ fp = (file_prio + 1) * (zone->recent_scanned[1] + 1);
+ fp /= zone->recent_rotated[1] + 1;
+
+ /* Normalize to percentages */
+ percent[0] = 100 * ap / (ap + fp + 1);
+ percent[1] = 100 - percent[0];
}
+
/*
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
*/
@@ -1236,36 +1244,41 @@ static unsigned long shrink_zone(int pri
unsigned long nr[NR_LRU_LISTS];
unsigned long nr_to_scan;
unsigned long nr_reclaimed = 0;
+ unsigned long percent[2]; /* anon @ 0; file @ 1 */
enum lru_list l;
- if (scan_global_lru(sc)) {
- /*
- * Add one to nr_to_scan just to make sure that the kernel
- * will slowly sift through the active list.
- */
- for_each_lru(l) {
- zone->lru[l].nr_scan += (zone_page_state(zone,
- NR_LRU_BASE + l) >> priority) + 1;
+ get_scan_ratio(zone, sc, percent);
+
+ for_each_lru(l) {
+ if (scan_global_lru(sc)) {
+ int file = is_file_lru(l);
+ int scan;
+ /*
+ * Add one to nr_to_scan just to make sure that the
+ * kernel will slowly sift through each list.
+ */
+ scan = zone_page_state(zone, NR_LRU_BASE + l);
+ scan >>= priority;
+ scan = (scan * percent[file]) / 100;
+ zone->lru[l].nr_scan += scan + 1;
nr[l] = zone->lru[l].nr_scan;
if (nr[l] >= sc->swap_cluster_max)
zone->lru[l].nr_scan = 0;
else
nr[l] = 0;
+ } else {
+ /*
+ * This reclaim occurs not because zone memory shortage
+ * but because memory controller hits its limit.
+ * Don't modify zone reclaim related data.
+ */
+ nr[l] = mem_cgroup_calc_reclaim(sc->mem_cgroup, zone,
+ priority, l);
}
- } else {
- /*
- * This reclaim occurs not because zone memory shortage but
- * because memory controller hits its limit.
- * Then, don't modify zone reclaim related data.
- */
- nr[LRU_ACTIVE] = mem_cgroup_calc_reclaim(sc->mem_cgroup,
- zone, priority, LRU_ACTIVE);
-
- nr[LRU_INACTIVE] = mem_cgroup_calc_reclaim(sc->mem_cgroup,
- zone, priority, LRU_INACTIVE);
}
- while (nr[LRU_ACTIVE] || nr[LRU_INACTIVE]) {
+ while (nr[LRU_ACTIVE_ANON] || nr[LRU_INACTIVE_ANON] ||
+ nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) {
for_each_lru(l) {
if (nr[l]) {
nr_to_scan = min(nr[l],
@@ -1338,7 +1351,7 @@ static unsigned long shrink_zones(int pr
return nr_reclaimed;
}
-
+
/*
* This is the main entry point to direct page reclaim.
*
@@ -1381,8 +1394,7 @@ static unsigned long do_try_to_free_page
if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
continue;
- lru_pages += zone_page_state(zone, NR_ACTIVE)
- + zone_page_state(zone, NR_INACTIVE);
+ lru_pages += zone_lru_pages(zone);
}
}
@@ -1584,8 +1596,7 @@ loop_again:
for (i = 0; i <= end_zone; i++) {
struct zone *zone = pgdat->node_zones + i;
- lru_pages += zone_page_state(zone, NR_ACTIVE)
- + zone_page_state(zone, NR_INACTIVE);
+ lru_pages += zone_lru_pages(zone);
}
/*
@@ -1629,8 +1640,7 @@ loop_again:
if (zone_is_all_unreclaimable(zone))
continue;
if (nr_slab == 0 && zone->pages_scanned >=
- (zone_page_state(zone, NR_ACTIVE)
- + zone_page_state(zone, NR_INACTIVE)) * 6)
+ (zone_lru_pages(zone) * 6))
zone_set_flag(zone,
ZONE_ALL_UNRECLAIMABLE);
/*
@@ -1684,7 +1694,7 @@ out:
/*
* The background pageout daemon, started as a kernel thread
- * from the init process.
+ * from the init process.
*
* This basically trickles out pages so that we have _some_
* free memory available even if there is no other activity
@@ -1778,6 +1788,14 @@ void wakeup_kswapd(struct zone *zone, in
wake_up_interruptible(&pgdat->kswapd_wait);
}
+unsigned long global_lru_pages(void)
+{
+ return global_page_state(NR_ACTIVE_ANON)
+ + global_page_state(NR_ACTIVE_FILE)
+ + global_page_state(NR_INACTIVE_ANON)
+ + global_page_state(NR_INACTIVE_FILE);
+}
+
#ifdef CONFIG_PM
/*
* Helper function for shrink_all_memory(). Tries to reclaim 'nr_pages' pages
@@ -1803,7 +1821,8 @@ static unsigned long shrink_all_zones(un
for_each_lru(l) {
/* For pass = 0 we don't shrink the active list */
- if (pass == 0 && l == LRU_ACTIVE)
+ if (pass == 0 &&
+ (l == LRU_ACTIVE || l == LRU_ACTIVE_FILE))
continue;
zone->lru[l].nr_scan +=
@@ -1825,11 +1844,6 @@ static unsigned long shrink_all_zones(un
return ret;
}
-static unsigned long count_lru_pages(void)
-{
- return global_page_state(NR_ACTIVE) + global_page_state(NR_INACTIVE);
-}
-
/*
* Try to free `nr_pages' of memory, system-wide, and return the number of
* freed pages.
@@ -1855,7 +1869,7 @@ unsigned long shrink_all_memory(unsigned
current->reclaim_state = &reclaim_state;
- lru_pages = count_lru_pages();
+ lru_pages = global_lru_pages();
nr_slab = global_page_state(NR_SLAB_RECLAIMABLE);
/* If slab caches are huge, it's better to hit them first */
while (nr_slab >= lru_pages) {
@@ -1898,7 +1912,7 @@ unsigned long shrink_all_memory(unsigned
reclaim_state.reclaimed_slab = 0;
shrink_slab(sc.nr_scanned, sc.gfp_mask,
- count_lru_pages());
+ global_lru_pages());
ret += reclaim_state.reclaimed_slab;
if (ret >= nr_pages)
goto out;
@@ -1915,7 +1929,7 @@ unsigned long shrink_all_memory(unsigned
if (!ret) {
do {
reclaim_state.reclaimed_slab = 0;
- shrink_slab(nr_pages, sc.gfp_mask, count_lru_pages());
+ shrink_slab(nr_pages, sc.gfp_mask, global_lru_pages());
ret += reclaim_state.reclaimed_slab;
} while (ret < nr_pages && reclaim_state.reclaimed_slab > 0);
}
Index: linux-2.6.26-rc5-mm2/mm/swap_state.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap_state.c 2008-06-10 13:34:48.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap_state.c 2008-06-10 13:35:23.000000000 -0400
@@ -303,7 +303,7 @@ struct page *read_swap_cache_async(swp_e
/*
* Initiate read into locked page and return.
*/
- lru_cache_add_active(new_page);
+ lru_cache_add_active_anon(new_page);
swap_readpage(NULL, new_page);
return new_page;
}
Index: linux-2.6.26-rc5-mm2/include/linux/mmzone.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mmzone.h 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mmzone.h 2008-06-10 13:35:23.000000000 -0400
@@ -82,21 +82,23 @@ enum zone_stat_item {
/* First 128 byte cacheline (assuming 64 bit words) */
NR_FREE_PAGES,
NR_LRU_BASE,
- NR_INACTIVE = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
- NR_ACTIVE, /* " " " " " */
+ NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
+ NR_ACTIVE_ANON, /* " " " " " */
+ NR_INACTIVE_FILE, /* " " " " " */
+ NR_ACTIVE_FILE, /* " " " " " */
NR_ANON_PAGES, /* Mapped anonymous pages */
NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
only modified from process context */
NR_FILE_PAGES,
NR_FILE_DIRTY,
NR_WRITEBACK,
- /* Second 128 byte cacheline */
NR_SLAB_RECLAIMABLE,
NR_SLAB_UNRECLAIMABLE,
NR_PAGETABLE, /* used for pagetables */
NR_UNSTABLE_NFS, /* NFS unstable pages */
NR_BOUNCE,
NR_VMSCAN_WRITE,
+ /* Second 128 byte cacheline */
NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */
#ifdef CONFIG_NUMA
NUMA_HIT, /* allocated in intended node */
@@ -108,17 +110,36 @@ enum zone_stat_item {
#endif
NR_VM_ZONE_STAT_ITEMS };
+/*
+ * We do arithmetic on the LRU lists in various places in the code,
+ * so it is important to keep the active lists LRU_ACTIVE higher in
+ * the array than the corresponding inactive lists, and to keep
+ * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
+ *
+ * This has to be kept in sync with the statistics in zone_stat_item
+ * above and the descriptions in vmstat_text in mm/vmstat.c
+ */
+#define LRU_BASE 0
+#define LRU_ACTIVE 1
+#define LRU_FILE 2
+
enum lru_list {
- LRU_BASE,
- LRU_INACTIVE=LRU_BASE, /* must match order of NR_[IN]ACTIVE */
- LRU_ACTIVE, /* " " " " " */
+ LRU_INACTIVE_ANON = LRU_BASE,
+ LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
+ LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
+ LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
NR_LRU_LISTS };
#define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
+static inline int is_file_lru(enum lru_list l)
+{
+ return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE);
+}
+
static inline int is_active_lru(enum lru_list l)
{
- return (l == LRU_ACTIVE);
+ return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE);
}
struct per_cpu_pages {
@@ -269,6 +290,18 @@ struct zone {
struct list_head list;
unsigned long nr_scan;
} lru[NR_LRU_LISTS];
+
+ /*
+ * The pageout code in vmscan.c keeps track of how many of the
+ * mem/swap backed and file backed pages are refeferenced.
+ * The higher the rotated/scanned ratio, the more valuable
+ * that cache is.
+ *
+ * The anon LRU stats live in [0], file LRU stats in [1]
+ */
+ unsigned long recent_rotated[2];
+ unsigned long recent_scanned[2];
+
unsigned long pages_scanned; /* since last reclaim */
unsigned long flags; /* zone flags, see below */
Index: linux-2.6.26-rc5-mm2/include/linux/mm_inline.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mm_inline.h 2008-06-10 13:34:48.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mm_inline.h 2008-06-10 13:35:23.000000000 -0400
@@ -5,7 +5,7 @@
* page_is_file_cache - should the page be on a file LRU or anon LRU?
* @page: the page to test
*
- * Returns !0 if @page is page cache page backed by a regular filesystem,
+ * Returns LRU_FILE if @page is page cache page backed by a regular filesystem,
* or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed.
* Used by functions that manipulate the LRU lists, to sort a page
* onto the right LRU list.
@@ -20,7 +20,7 @@ static inline int page_is_file_cache(str
return 0;
/* The page is page cache backed by a normal filesystem. */
- return 1;
+ return LRU_FILE;
}
static inline void
@@ -38,39 +38,64 @@ del_page_from_lru_list(struct zone *zone
}
static inline void
-add_page_to_active_list(struct zone *zone, struct page *page)
+add_page_to_inactive_anon_list(struct zone *zone, struct page *page)
{
- add_page_to_lru_list(zone, page, LRU_ACTIVE);
+ add_page_to_lru_list(zone, page, LRU_INACTIVE_ANON);
}
static inline void
-add_page_to_inactive_list(struct zone *zone, struct page *page)
+add_page_to_active_anon_list(struct zone *zone, struct page *page)
{
- add_page_to_lru_list(zone, page, LRU_INACTIVE);
+ add_page_to_lru_list(zone, page, LRU_ACTIVE_ANON);
}
static inline void
-del_page_from_active_list(struct zone *zone, struct page *page)
+add_page_to_inactive_file_list(struct zone *zone, struct page *page)
{
- del_page_from_lru_list(zone, page, LRU_ACTIVE);
+ add_page_to_lru_list(zone, page, LRU_INACTIVE_FILE);
}
static inline void
-del_page_from_inactive_list(struct zone *zone, struct page *page)
+add_page_to_active_file_list(struct zone *zone, struct page *page)
{
- del_page_from_lru_list(zone, page, LRU_INACTIVE);
+ add_page_to_lru_list(zone, page, LRU_ACTIVE_FILE);
+}
+
+static inline void
+del_page_from_inactive_anon_list(struct zone *zone, struct page *page)
+{
+ del_page_from_lru_list(zone, page, LRU_INACTIVE_ANON);
+}
+
+static inline void
+del_page_from_active_anon_list(struct zone *zone, struct page *page)
+{
+ del_page_from_lru_list(zone, page, LRU_ACTIVE_ANON);
+}
+
+static inline void
+del_page_from_inactive_file_list(struct zone *zone, struct page *page)
+{
+ del_page_from_lru_list(zone, page, LRU_INACTIVE_FILE);
+}
+
+static inline void
+del_page_from_active_file_list(struct zone *zone, struct page *page)
+{
+ del_page_from_lru_list(zone, page, LRU_INACTIVE_FILE);
}
static inline void
del_page_from_lru(struct zone *zone, struct page *page)
{
- enum lru_list l = LRU_INACTIVE;
+ enum lru_list l = LRU_BASE;
list_del(&page->lru);
if (PageActive(page)) {
__ClearPageActive(page);
- l = LRU_ACTIVE;
+ l += LRU_ACTIVE;
}
+ l += page_is_file_cache(page);
__dec_zone_state(zone, NR_LRU_BASE + l);
}
@@ -87,6 +112,7 @@ static inline enum lru_list page_lru(str
if (PageActive(page))
lru += LRU_ACTIVE;
+ lru += page_is_file_cache(page);
return lru;
}
Index: linux-2.6.26-rc5-mm2/include/linux/pagevec.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/pagevec.h 2008-06-10 13:34:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/pagevec.h 2008-06-10 13:35:23.000000000 -0400
@@ -81,20 +81,37 @@ static inline void pagevec_free(struct p
__pagevec_free(pvec);
}
-static inline void __pagevec_lru_add(struct pagevec *pvec)
+static inline void __pagevec_lru_add_anon(struct pagevec *pvec)
{
- ____pagevec_lru_add(pvec, LRU_INACTIVE);
+ ____pagevec_lru_add(pvec, LRU_INACTIVE_ANON);
}
-static inline void __pagevec_lru_add_active(struct pagevec *pvec)
+static inline void __pagevec_lru_add_active_anon(struct pagevec *pvec)
{
- ____pagevec_lru_add(pvec, LRU_ACTIVE);
+ ____pagevec_lru_add(pvec, LRU_ACTIVE_ANON);
}
-static inline void pagevec_lru_add(struct pagevec *pvec)
+static inline void __pagevec_lru_add_file(struct pagevec *pvec)
+{
+ ____pagevec_lru_add(pvec, LRU_INACTIVE_FILE);
+}
+
+static inline void __pagevec_lru_add_active_file(struct pagevec *pvec)
+{
+ ____pagevec_lru_add(pvec, LRU_ACTIVE_FILE);
+}
+
+
+static inline void pagevec_lru_add_file(struct pagevec *pvec)
+{
+ if (pagevec_count(pvec))
+ __pagevec_lru_add_file(pvec);
+}
+
+static inline void pagevec_lru_add_anon(struct pagevec *pvec)
{
if (pagevec_count(pvec))
- __pagevec_lru_add(pvec);
+ __pagevec_lru_add_anon(pvec);
}
#endif /* _LINUX_PAGEVEC_H */
Index: linux-2.6.26-rc5-mm2/include/linux/vmstat.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/vmstat.h 2008-06-10 10:46:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/vmstat.h 2008-06-10 13:35:23.000000000 -0400
@@ -159,6 +159,16 @@ static inline unsigned long zone_page_st
return x;
}
+extern unsigned long global_lru_pages(void);
+
+static inline unsigned long zone_lru_pages(struct zone *zone)
+{
+ return (zone_page_state(zone, NR_ACTIVE_ANON)
+ + zone_page_state(zone, NR_ACTIVE_FILE)
+ + zone_page_state(zone, NR_INACTIVE_ANON)
+ + zone_page_state(zone, NR_INACTIVE_FILE));
+}
+
#ifdef CONFIG_NUMA
/*
* Determine the per node value of a stat item. This function
Index: linux-2.6.26-rc5-mm2/mm/page-writeback.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page-writeback.c 2008-06-10 10:46:19.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page-writeback.c 2008-06-10 13:35:23.000000000 -0400
@@ -329,9 +329,7 @@ static unsigned long highmem_dirtyable_m
struct zone *z =
&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
- x += zone_page_state(z, NR_FREE_PAGES)
- + zone_page_state(z, NR_INACTIVE)
- + zone_page_state(z, NR_ACTIVE);
+ x += zone_page_state(z, NR_FREE_PAGES) + zone_lru_pages(z);
}
/*
* Make sure that the number of highmem pages is never larger
@@ -355,9 +353,7 @@ unsigned long determine_dirtyable_memory
{
unsigned long x;
- x = global_page_state(NR_FREE_PAGES)
- + global_page_state(NR_INACTIVE)
- + global_page_state(NR_ACTIVE);
+ x = global_page_state(NR_FREE_PAGES) + global_lru_pages();
if (!vm_highmem_is_dirtyable)
x -= highmem_dirtyable_memory(x);
Index: linux-2.6.26-rc5-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/swap.h 2008-06-10 13:34:07.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/swap.h 2008-06-10 13:35:23.000000000 -0400
@@ -184,14 +184,24 @@ extern void swap_setup(void);
* lru_cache_add: add a page to the page lists
* @page: the page to add
*/
-static inline void lru_cache_add(struct page *page)
+static inline void lru_cache_add_anon(struct page *page)
{
- __lru_cache_add(page, LRU_INACTIVE);
+ __lru_cache_add(page, LRU_INACTIVE_ANON);
}
-static inline void lru_cache_add_active(struct page *page)
+static inline void lru_cache_add_active_anon(struct page *page)
{
- __lru_cache_add(page, LRU_ACTIVE);
+ __lru_cache_add(page, LRU_ACTIVE_ANON);
+}
+
+static inline void lru_cache_add_file(struct page *page)
+{
+ __lru_cache_add(page, LRU_INACTIVE_FILE);
+}
+
+static inline void lru_cache_add_active_file(struct page *page)
+{
+ __lru_cache_add(page, LRU_ACTIVE_FILE);
}
/* linux/mm/vmscan.c */
@@ -199,7 +209,7 @@ extern unsigned long try_to_free_pages(s
gfp_t gfp_mask);
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
gfp_t gfp_mask);
-extern int __isolate_lru_page(struct page *page, int mode);
+extern int __isolate_lru_page(struct page *page, int mode, int file);
extern unsigned long shrink_all_memory(unsigned long nr_pages);
extern int vm_swappiness;
extern int remove_mapping(struct address_space *mapping, struct page *page);
Index: linux-2.6.26-rc5-mm2/include/linux/memcontrol.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/memcontrol.h 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/memcontrol.h 2008-06-10 13:35:23.000000000 -0400
@@ -44,7 +44,7 @@ extern unsigned long mem_cgroup_isolate_
unsigned long *scanned, int order,
int mode, struct zone *z,
struct mem_cgroup *mem_cont,
- int active);
+ int active, int file);
extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
Index: linux-2.6.26-rc5-mm2/mm/memcontrol.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memcontrol.c 2008-06-10 13:18:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memcontrol.c 2008-06-10 13:35:23.000000000 -0400
@@ -162,6 +162,7 @@ struct page_cgroup {
};
#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
+#define PAGE_CGROUP_FLAG_FILE (0x4) /* page is file system backed */
static int page_cgroup_nid(struct page_cgroup *pc)
{
@@ -280,8 +281,12 @@ static void unlock_page_cgroup(struct pa
static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc)
{
- int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
- int lru = !!from;
+ int lru = LRU_BASE;
+
+ if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
+ lru += LRU_ACTIVE;
+ if (pc->flags & PAGE_CGROUP_FLAG_FILE)
+ lru += LRU_FILE;
MEM_CGROUP_ZSTAT(mz, lru) -= 1;
@@ -292,10 +297,12 @@ static void __mem_cgroup_remove_list(str
static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc)
{
- int lru = LRU_INACTIVE;
+ int lru = LRU_BASE;
if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
lru += LRU_ACTIVE;
+ if (pc->flags & PAGE_CGROUP_FLAG_FILE)
+ lru += LRU_FILE;
MEM_CGROUP_ZSTAT(mz, lru) += 1;
list_add(&pc->lru, &mz->lists[lru]);
@@ -306,10 +313,9 @@ static void __mem_cgroup_add_list(struct
static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
{
struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
- int lru = LRU_INACTIVE;
-
- if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
- lru += LRU_ACTIVE;
+ int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
+ int file = pc->flags & PAGE_CGROUP_FLAG_FILE;
+ int lru = LRU_FILE * !!file + !!from;
MEM_CGROUP_ZSTAT(mz, lru) -= 1;
@@ -318,7 +324,7 @@ static void __mem_cgroup_move_lists(stru
else
pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
- lru = !!active;
+ lru = LRU_FILE * !!file + !!active;
MEM_CGROUP_ZSTAT(mz, lru) += 1;
list_move(&pc->lru, &mz->lists[lru]);
}
@@ -380,21 +386,6 @@ int mem_cgroup_calc_mapped_ratio(struct
}
/*
- * This function is called from vmscan.c. In page reclaiming loop. balance
- * between active and inactive list is calculated. For memory controller
- * page reclaiming, we should use using mem_cgroup's imbalance rather than
- * zone's global lru imbalance.
- */
-long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem)
-{
- unsigned long active, inactive;
- /* active and inactive are the number of pages. 'long' is ok.*/
- active = mem_cgroup_get_all_zonestat(mem, LRU_ACTIVE);
- inactive = mem_cgroup_get_all_zonestat(mem, LRU_INACTIVE);
- return (long) (active / (inactive + 1));
-}
-
-/*
* prev_priority control...this will be used in memory reclaim path.
*/
int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
@@ -439,7 +430,7 @@ unsigned long mem_cgroup_isolate_pages(u
unsigned long *scanned, int order,
int mode, struct zone *z,
struct mem_cgroup *mem_cont,
- int active)
+ int active, int file)
{
unsigned long nr_taken = 0;
struct page *page;
@@ -450,7 +441,7 @@ unsigned long mem_cgroup_isolate_pages(u
int nid = z->zone_pgdat->node_id;
int zid = zone_idx(z);
struct mem_cgroup_per_zone *mz;
- int lru = !!active;
+ int lru = LRU_FILE * !!file + !!active;
BUG_ON(!mem_cont);
mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
@@ -466,6 +457,9 @@ unsigned long mem_cgroup_isolate_pages(u
if (unlikely(!PageLRU(page)))
continue;
+ /*
+ * TODO: play better with lumpy reclaim, grabbing anything.
+ */
if (PageActive(page) && !active) {
__mem_cgroup_move_lists(pc, true);
continue;
@@ -478,7 +472,7 @@ unsigned long mem_cgroup_isolate_pages(u
scan++;
list_move(&pc->lru, &pc_list);
- if (__isolate_lru_page(page, mode) == 0) {
+ if (__isolate_lru_page(page, mode, file) == 0) {
list_move(&page->lru, dst);
nr_taken++;
}
@@ -562,9 +556,11 @@ static int mem_cgroup_charge_common(stru
* If a page is accounted as a page cache, insert to inactive list.
* If anon, insert to active list.
*/
- if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
+ if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE) {
pc->flags = PAGE_CGROUP_FLAG_CACHE;
- else
+ if (page_is_file_cache(page))
+ pc->flags |= PAGE_CGROUP_FLAG_FILE;
+ } else
pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
lock_page_cgroup(page);
@@ -915,14 +911,21 @@ static int mem_control_stat_show(struct
}
/* showing # of active pages */
{
- unsigned long active, inactive;
+ unsigned long active_anon, inactive_anon;
+ unsigned long active_file, inactive_file;
- inactive = mem_cgroup_get_all_zonestat(mem_cont,
- LRU_INACTIVE);
- active = mem_cgroup_get_all_zonestat(mem_cont,
- LRU_ACTIVE);
- cb->fill(cb, "active", (active) * PAGE_SIZE);
- cb->fill(cb, "inactive", (inactive) * PAGE_SIZE);
+ inactive_anon = mem_cgroup_get_all_zonestat(mem_cont,
+ LRU_INACTIVE_ANON);
+ active_anon = mem_cgroup_get_all_zonestat(mem_cont,
+ LRU_ACTIVE_ANON);
+ inactive_file = mem_cgroup_get_all_zonestat(mem_cont,
+ LRU_INACTIVE_FILE);
+ active_file = mem_cgroup_get_all_zonestat(mem_cont,
+ LRU_ACTIVE_FILE);
+ cb->fill(cb, "active_anon", (active_anon) * PAGE_SIZE);
+ cb->fill(cb, "inactive_anon", (inactive_anon) * PAGE_SIZE);
+ cb->fill(cb, "active_file", (active_file) * PAGE_SIZE);
+ cb->fill(cb, "inactive_file", (inactive_file) * PAGE_SIZE);
}
return 0;
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 07/24] vmscan: second chance replacement for anonymous pages
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (5 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 06/24] vmscan: split LRU lists into anon & file sets Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 08/24] vmscan: fix pagecache reclaim referenced bit check Rik van Riel
` (17 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-second-chance-replacement-for-anonymous-pages.patch --]
[-- Type: text/plain, Size: 8690 bytes --]
From: Rik van Riel <riel@redhat.com>
We avoid evicting and scanning anonymous pages for the most part, but
under some workloads we can end up with most of memory filled with
anonymous pages. At that point, we suddenly need to clear the referenced
bits on all of memory, which can take ages on very large memory systems.
We can reduce the maximum number of pages that need to be scanned by
not taking the referenced state into account when deactivating an
anonymous page. After all, every anonymous page starts out referenced,
so why check?
If an anonymous page gets referenced again before it reaches the end
of the inactive list, we move it back to the active list.
To keep the maximum amount of necessary work reasonable, we scale the
active to inactive ratio with the size of memory, using the formula
active:inactive ratio = sqrt(memory in GB * 10).
Kswapd CPU use now seems to scale by the amount of pageout bandwidth,
instead of by the amount of memory present in the system.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
include/linux/mm_inline.h | 19 +++++++++++++++++
include/linux/mmzone.h | 6 +++++
mm/page_alloc.c | 41 ++++++++++++++++++++++++++++++++++++++
mm/vmscan.c | 49 +++++++++++++++++++++++++++++++++++++++-------
mm/vmstat.c | 6 +++--
5 files changed, 112 insertions(+), 9 deletions(-)
Index: linux-2.6.26-rc5-mm2/include/linux/mm_inline.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mm_inline.h 2008-06-10 13:35:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mm_inline.h 2008-06-10 13:35:58.000000000 -0400
@@ -117,4 +117,23 @@ static inline enum lru_list page_lru(str
return lru;
}
+/**
+ * inactive_anon_is_low - check if anonymous pages need to be deactivated
+ * @zone: zone to check
+ *
+ * Returns true if the zone does not have enough inactive anon pages,
+ * meaning some active anon pages need to be deactivated.
+ */
+static inline int inactive_anon_is_low(struct zone *zone)
+{
+ unsigned long active, inactive;
+
+ active = zone_page_state(zone, NR_ACTIVE_ANON);
+ inactive = zone_page_state(zone, NR_INACTIVE_ANON);
+
+ if (inactive * zone->inactive_ratio < active)
+ return 1;
+
+ return 0;
+}
#endif
Index: linux-2.6.26-rc5-mm2/include/linux/mmzone.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mmzone.h 2008-06-10 13:35:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mmzone.h 2008-06-10 13:35:58.000000000 -0400
@@ -323,6 +323,12 @@ struct zone {
*/
int prev_priority;
+ /*
+ * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
+ * this zone's LRU. Maintained by the pageout code.
+ */
+ unsigned int inactive_ratio;
+
ZONE_PADDING(_pad2_)
/* Rarely used or read-mostly fields */
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 13:35:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 13:35:58.000000000 -0400
@@ -4194,6 +4194,46 @@ void setup_per_zone_pages_min(void)
calculate_totalreserve_pages();
}
+/**
+ * setup_per_zone_inactive_ratio - called when min_free_kbytes changes.
+ *
+ * The inactive anon list should be small enough that the VM never has to
+ * do too much work, but large enough that each inactive page has a chance
+ * to be referenced again before it is swapped out.
+ *
+ * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
+ * INACTIVE_ANON pages on this zone's LRU, maintained by the
+ * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
+ * the anonymous pages are kept on the inactive list.
+ *
+ * total target max
+ * memory ratio inactive anon
+ * -------------------------------------
+ * 10MB 1 5MB
+ * 100MB 1 50MB
+ * 1GB 3 250MB
+ * 10GB 10 0.9GB
+ * 100GB 31 3GB
+ * 1TB 101 10GB
+ * 10TB 320 32GB
+ */
+void setup_per_zone_inactive_ratio(void)
+{
+ struct zone *zone;
+
+ for_each_zone(zone) {
+ unsigned int gb, ratio;
+
+ /* Zone size in gigabytes */
+ gb = zone->present_pages >> (30 - PAGE_SHIFT);
+ ratio = int_sqrt(10 * gb);
+ if (!ratio)
+ ratio = 1;
+
+ zone->inactive_ratio = ratio;
+ }
+}
+
/*
* Initialise min_free_kbytes.
*
@@ -4231,6 +4271,7 @@ static int __init init_per_zone_pages_mi
min_free_kbytes = 65536;
setup_per_zone_pages_min();
setup_per_zone_lowmem_reserve();
+ setup_per_zone_inactive_ratio();
return 0;
}
module_init(init_per_zone_pages_min)
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 13:35:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 13:35:58.000000000 -0400
@@ -1056,17 +1056,32 @@ static void shrink_active_list(unsigned
__mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved);
spin_unlock_irq(&zone->lru_lock);
+ pgmoved = 0;
while (!list_empty(&l_hold)) {
cond_resched();
page = lru_to_page(&l_hold);
list_del(&page->lru);
- if (page_referenced(page, 0, sc->mem_cgroup))
- list_add(&page->lru, &l_active);
- else
+ if (page_referenced(page, 0, sc->mem_cgroup)) {
+ pgmoved++;
+ if (file) {
+ /* Referenced file pages stay active. */
+ list_add(&page->lru, &l_active);
+ } else {
+ /* Anonymous pages always get deactivated. */
+ list_add(&page->lru, &l_inactive);
+ }
+ } else
list_add(&page->lru, &l_inactive);
}
/*
+ * Count the referenced pages as rotated, even when they are moved
+ * to the inactive list. This helps balance scan pressure between
+ * file and anonymous pages in get_scan_ratio.
+ */
+ zone->recent_rotated[!!file] += pgmoved;
+
+ /*
* Now put the pages back on the appropriate [file or anon] inactive
* and active lists.
*/
@@ -1127,7 +1142,6 @@ static void shrink_active_list(unsigned
}
}
__mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
- zone->recent_rotated[!!file] += pgmoved;
__count_zone_vm_events(PGREFILL, zone, pgscanned);
__count_vm_events(PGDEACTIVATE, pgdeactivate);
@@ -1143,7 +1157,13 @@ static unsigned long shrink_list(enum lr
{
int file = is_file_lru(lru);
- if (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE) {
+ if (lru == LRU_ACTIVE_FILE) {
+ shrink_active_list(nr_to_scan, zone, sc, priority, file);
+ return 0;
+ }
+
+ if (lru == LRU_ACTIVE_ANON &&
+ (!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
shrink_active_list(nr_to_scan, zone, sc, priority, file);
return 0;
}
@@ -1277,8 +1297,8 @@ static unsigned long shrink_zone(int pri
}
}
- while (nr[LRU_ACTIVE_ANON] || nr[LRU_INACTIVE_ANON] ||
- nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) {
+ while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
+ nr[LRU_INACTIVE_FILE]) {
for_each_lru(l) {
if (nr[l]) {
nr_to_scan = min(nr[l],
@@ -1291,6 +1311,13 @@ static unsigned long shrink_zone(int pri
}
}
+ /*
+ * Even if we did not try to evict anon pages at all, we want to
+ * rebalance the anon lru active/inactive ratio.
+ */
+ if (scan_global_lru(sc) && inactive_anon_is_low(zone))
+ shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
+
throttle_vm_writeout(sc->gfp_mask);
return nr_reclaimed;
}
@@ -1584,6 +1611,14 @@ loop_again:
priority != DEF_PRIORITY)
continue;
+ /*
+ * Do some background aging of the anon list, to give
+ * pages a chance to be referenced before reclaiming.
+ */
+ if (inactive_anon_is_low(zone))
+ shrink_active_list(SWAP_CLUSTER_MAX, zone,
+ &sc, priority, 0);
+
if (!zone_watermark_ok(zone, order, zone->pages_high,
0, 0)) {
end_zone = i;
Index: linux-2.6.26-rc5-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmstat.c 2008-06-10 13:35:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmstat.c 2008-06-10 13:35:58.000000000 -0400
@@ -721,10 +721,12 @@ static void zoneinfo_show_print(struct s
seq_printf(m,
"\n all_unreclaimable: %u"
"\n prev_priority: %i"
- "\n start_pfn: %lu",
+ "\n start_pfn: %lu"
+ "\n inactive_ratio: %u",
zone_is_all_unreclaimable(zone),
zone->prev_priority,
- zone->zone_start_pfn);
+ zone->zone_start_pfn,
+ zone->inactive_ratio);
seq_putc(m, '\n');
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 08/24] vmscan: fix pagecache reclaim referenced bit check
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (6 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 07/24] vmscan: second chance replacement for anonymous pages Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 09/24] vmscan: add newly swapped in pages to the inactive list Rik van Riel
` (16 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, Martin Bligh
[-- Attachment #1: vmscan-fix-pagecache-reclaim-referenced-bit-check.patch --]
[-- Type: text/plain, Size: 1591 bytes --]
From: Rik van Riel <riel@redhat.com>
The -mm tree contains the patch
vmscan-give-referenced-active-and-unmapped-pages-a-second-trip-around-the-lru.patch
which gives referenced pagecache pages another trip around
the active list. This seems to help keep frequently accessed
pagecache pages in memory.
However, it means that pagecache pages that get moved to the
inactive list do not have their referenced bit set, and the
next access to the page will not get it moved back to the active
list. This patch sets the referenced bit on pagecache pages
that get deactivated, so the next access to the page will promote
it back to the active list.
This works because shrink_page_list() will reclaim unmapped
pages with the referenced bit set.
Signed-off-by: Rik van Riel <riel@redhat.com>
---
mm/vmscan.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 13:35:58.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 13:40:19.000000000 -0400
@@ -1070,8 +1070,16 @@ static void shrink_active_list(unsigned
/* Anonymous pages always get deactivated. */
list_add(&page->lru, &l_inactive);
}
- } else
+ } else {
list_add(&page->lru, &l_inactive);
+ if (!page_mapping_inuse(page))
+ /*
+ * Bypass use-once, make the next access
+ * count. See mark_page_accessed and
+ * shrink_page_list.
+ */
+ SetPageReferenced(page);
+ }
}
/*
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 09/24] vmscan: add newly swapped in pages to the inactive list
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (7 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 08/24] vmscan: fix pagecache reclaim referenced bit check Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 10/24] more aggressively use lumpy reclaim Rik van Riel
` (15 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-add-newly-swapped-in-pages-to-the-inactive-list.patch --]
[-- Type: text/plain, Size: 1076 bytes --]
From: Rik van Riel <riel@redhat.com>
Swapin_readahead can read in a lot of data that the processes in
memory never need. Adding swap cache pages to the inactive list
prevents them from putting too much pressure on the working set.
This has the potential to help the programs that are already in
memory, but it could also be a disadvantage to processes that
are trying to get swapped in.
Signed-off-by: Rik van Riel <riel@redhat.com>
---
mm/swap_state.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.26-rc5-mm2/mm/swap_state.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap_state.c 2008-06-10 13:35:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap_state.c 2008-06-10 13:40:46.000000000 -0400
@@ -303,7 +303,7 @@ struct page *read_swap_cache_async(swp_e
/*
* Initiate read into locked page and return.
*/
- lru_cache_add_active_anon(new_page);
+ lru_cache_add_anon(new_page);
swap_readpage(NULL, new_page);
return new_page;
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 10/24] more aggressively use lumpy reclaim
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (8 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 09/24] vmscan: add newly swapped in pages to the inactive list Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 11/24] pageflag helpers for configed-out flags Rik van Riel
` (14 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-more-aggressively-use-lumpy-reclaim.patch --]
[-- Type: text/plain, Size: 2547 bytes --]
From: Rik van Riel <riel@redhat.com>
During an AIM7 run on a 16GB system, fork started failing around
32000 threads, despite the system having plenty of free swap and
15GB of pageable memory. This was on x86-64, so 8k stacks.
If a higher order allocation fails, we can either:
- keep evicting pages off the end of the LRUs and hope that
we eventually create a contiguous region; this is somewhat
unlikely if the system is under enough stress by new
allocations
- after trying normal eviction for a bit, use lumpy reclaim
This patch switches the system to lumpy reclaim if the VM
is having trouble freeing enough pages, using the same
threshold for detection as used by pageout congestion wait.
Signed-off-by: Rik van Riel <riel@redhat.com>
---
mm/vmscan.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 13:40:19.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 13:41:25.000000000 -0400
@@ -875,7 +875,8 @@ int isolate_lru_page(struct page *page)
* of reclaimed pages
*/
static unsigned long shrink_inactive_list(unsigned long max_scan,
- struct zone *zone, struct scan_control *sc, int file)
+ struct zone *zone, struct scan_control *sc,
+ int priority, int file)
{
LIST_HEAD(page_list);
struct pagevec pvec;
@@ -893,8 +894,19 @@ static unsigned long shrink_inactive_lis
unsigned long nr_freed;
unsigned long nr_active;
unsigned int count[NR_LRU_LISTS] = { 0, };
- int mode = (sc->order > PAGE_ALLOC_COSTLY_ORDER) ?
- ISOLATE_BOTH : ISOLATE_INACTIVE;
+ int mode = ISOLATE_INACTIVE;
+
+ /*
+ * If we need a large contiguous chunk of memory, or have
+ * trouble getting a small set of contiguous pages, we
+ * will reclaim both active and inactive pages.
+ *
+ * We use the same threshold as pageout congestion_wait below.
+ */
+ if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
+ mode = ISOLATE_BOTH;
+ else if (sc->order && priority < DEF_PRIORITY - 2)
+ mode = ISOLATE_BOTH;
nr_taken = sc->isolate_pages(sc->swap_cluster_max,
&page_list, &nr_scan, sc->order, mode,
@@ -1175,7 +1187,7 @@ static unsigned long shrink_list(enum lr
shrink_active_list(nr_to_scan, zone, sc, priority, file);
return 0;
}
- return shrink_inactive_list(nr_to_scan, zone, sc, file);
+ return shrink_inactive_list(nr_to_scan, zone, sc, priority, file);
}
/*
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (9 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 10/24] more aggressively use lumpy reclaim Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 20:01 ` Andrew Morton
2008-06-11 18:42 ` [PATCH -mm 12/24] Unevictable LRU Infrastructure Rik van Riel
` (13 subsequent siblings)
24 siblings, 1 reply; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, Lee Schermerhorn
[-- Attachment #1: vmscan-pageflag-helpers-for-configed-out-flags.patch --]
[-- Type: text/plain, Size: 1361 bytes --]
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
Define proper false/noop inline functions for noreclaim page
flags when !defined(CONFIG_NORECLAIM_LRU)
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
include/linux/page-flags.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
Index: linux-2.6.26-rc5-mm2/include/linux/page-flags.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/page-flags.h 2008-06-10 13:34:48.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/page-flags.h 2008-06-10 13:44:55.000000000 -0400
@@ -162,6 +162,18 @@ static inline int Page##uname(struct pag
#define TESTSCFLAG(uname, lname) \
TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
+#define SETPAGEFLAG_NOOP(uname) \
+static inline void SetPage##uname(struct page *page) { }
+
+#define CLEARPAGEFLAG_NOOP(uname) \
+static inline void ClearPage##uname(struct page *page) { }
+
+#define __CLEARPAGEFLAG_NOOP(uname) \
+static inline void __ClearPage##uname(struct page *page) { }
+
+#define TESTCLEARFLAG_FALSE(uname) \
+static inline int TestClearPage##uname(struct page *page) { return 0; }
+
struct page; /* forward declaration */
PAGEFLAG(Locked, locked) TESTSCFLAG(Locked, locked)
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 12/24] Unevictable LRU Infrastructure
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (10 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 11/24] pageflag helpers for configed-out flags Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 13/24] Unevictable LRU Page Statistics Rik van Riel
` (12 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, linux-mm, Eric Whitney
[-- Attachment #1: vmscan-noreclaim-lru-infrastructure.patch --]
[-- Type: text/plain, Size: 33714 bytes --]
From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
When the system contains lots of mlocked or otherwise unevictable
pages, the pageout code (kswapd) can spend lots of time scanning
over these pages. Worse still, the presence of lots of unevictable
pages can confuse kswapd into thinking that more aggressive pageout
modes are required, resulting in all kinds of bad behaviour.
Infrastructure to manage pages excluded from reclaim--i.e., hidden
from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked
to maintain "unevictable" pages on a separate per-zone LRU list,
to "hide" them from vmscan.
Kosaki Motohiro added the support for the memory controller unevictable
lru list.
Pages on the unevictable list have both PG_unevictable and PG_lru set.
Thus, PG_unevictable is analogous to and mutually exclusive with
PG_active--it specifies which LRU list the page is on.
The unevictable infrastructure is enabled by a new mm Kconfig option
[CONFIG_]UNEVICTABLE_LRU.
A new function 'page_evictable(page, vma)' in vmscan.c tests whether
or not a page may be evictable. Subsequent patches will add the various
!evictable tests. We'll want to keep these tests light-weight for
use in shrink_active_list() and, possibly, the fault path.
To avoid races between tasks putting pages [back] onto an LRU list and
tasks that might be moving the page from non-evictable to evictable
state, one should test evictability under page lock and place
nonevictable pages directly on the unevictable list before dropping the
lock. Otherwise, we risk "stranding" evictable pages on the unevictable
list. It's OK to use the pagevec caches for evictable pages. The new
function 'putback_lru_page()'--inverse to 'isolate_lru_page()'--handles
this transition, including potential page truncation while the page is
unlocked.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
include/linux/memcontrol.h | 1
include/linux/mm_inline.h | 23 ++++--
include/linux/mmzone.h | 24 ++++++-
include/linux/page-flags.h | 13 +++
include/linux/pagevec.h | 1
include/linux/swap.h | 12 +++
mm/Kconfig | 10 +++
mm/internal.h | 26 +++++++
mm/memcontrol.c | 73 +++++++++++++---------
mm/mempolicy.c | 2
mm/migrate.c | 68 +++++++++++++-------
mm/page_alloc.c | 9 ++
mm/swap.c | 40 ++++++++++--
mm/vmscan.c | 148 ++++++++++++++++++++++++++++++++++++++++-----
14 files changed, 370 insertions(+), 80 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/Kconfig
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/Kconfig 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/Kconfig 2008-06-10 16:25:49.000000000 -0400
@@ -205,3 +205,13 @@ config NR_QUICK
config VIRT_TO_BUS
def_bool y
depends on !ARCH_NO_VIRT_TO_BUS
+
+config UNEVICTABLE_LRU
+ bool "Add LRU list to track non-evictable pages"
+ default y
+ help
+ Keeps unevictable pages off of the active and inactive pageout
+ lists, so kswapd will not waste CPU time or have its balancing
+ algorithms thrown off by scanning these pages. Selecting this
+ will use one page flag and increase the code size a little,
+ say Y unless you know what you are doing.
Index: linux-2.6.26-rc5-mm2/include/linux/page-flags.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/page-flags.h 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/page-flags.h 2008-06-10 22:11:01.000000000 -0400
@@ -94,6 +94,9 @@ enum pageflags {
PG_reclaim, /* To be reclaimed asap */
PG_buddy, /* Page is free, on buddy lists */
PG_swapbacked, /* Page is backed by RAM/swap */
+#ifdef CONFIG_UNEVICTABLE_LRU
+ PG_unevictable, /* Page is "unevictable" */
+#endif
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PG_uncached, /* Page has been mapped as uncached */
#endif
@@ -182,6 +185,7 @@ PAGEFLAG(Referenced, referenced) TESTCLE
PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
+ TESTCLEARFLAG(Active, active)
__PAGEFLAG(Slab, slab)
PAGEFLAG(Checked, checked) /* Used by some filesystems */
PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
@@ -225,6 +229,15 @@ PAGEFLAG(SwapCache, swapcache)
PAGEFLAG_FALSE(SwapCache)
#endif
+#ifdef CONFIG_UNEVICTABLE_LRU
+PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
+ TESTCLEARFLAG(Unevictable, unevictable)
+#else
+PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable)
+ SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable)
+ __CLEARPAGEFLAG_NOOP(Unevictable)
+#endif
+
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PAGEFLAG(Uncached, uncached)
#else
Index: linux-2.6.26-rc5-mm2/include/linux/mmzone.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mmzone.h 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mmzone.h 2008-06-10 22:11:01.000000000 -0400
@@ -86,6 +86,11 @@ enum zone_stat_item {
NR_ACTIVE_ANON, /* " " " " " */
NR_INACTIVE_FILE, /* " " " " " */
NR_ACTIVE_FILE, /* " " " " " */
+#ifdef CONFIG_UNEVICTABLE_LRU
+ NR_UNEVICTABLE, /* " " " " " */
+#else
+ NR_UNEVICTABLE = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */
+#endif
NR_ANON_PAGES, /* Mapped anonymous pages */
NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
only modified from process context */
@@ -128,10 +133,18 @@ enum lru_list {
LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
- NR_LRU_LISTS };
+#ifdef CONFIG_UNEVICTABLE_LRU
+ LRU_UNEVICTABLE,
+#else
+ LRU_UNEVICTABLE = LRU_ACTIVE_FILE, /* avoid compiler errors in dead code */
+#endif
+ NR_LRU_LISTS
+};
#define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
+#define for_each_evictable_lru(l) for (l = 0; l <= LRU_ACTIVE_FILE; l++)
+
static inline int is_file_lru(enum lru_list l)
{
return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE);
@@ -142,6 +155,15 @@ static inline int is_active_lru(enum lru
return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE);
}
+static inline int is_unevictable_lru(enum lru_list l)
+{
+#ifdef CONFIG_UNEVICTABLE_LRU
+ return (l == LRU_UNEVICTABLE);
+#else
+ return 0;
+#endif
+}
+
struct per_cpu_pages {
int count; /* number of pages in the list */
int high; /* high watermark, emptying needed */
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 22:11:01.000000000 -0400
@@ -241,6 +241,9 @@ static void bad_page(struct page *page)
1 << PG_private |
1 << PG_locked |
1 << PG_active |
+#ifdef CONFIG_UNEVICTABLE_LRU
+ 1 << PG_unevictable |
+#endif
1 << PG_dirty |
1 << PG_reclaim |
1 << PG_slab |
@@ -474,6 +477,9 @@ static inline int free_pages_check(struc
1 << PG_swapcache |
1 << PG_writeback |
1 << PG_reserved |
+#ifdef CONFIG_UNEVICTABLE_LRU
+ 1 << PG_unevictable |
+#endif
1 << PG_buddy ))))
bad_page(page);
if (PageDirty(page))
@@ -625,6 +631,9 @@ static int prep_new_page(struct page *pa
1 << PG_private |
1 << PG_locked |
1 << PG_active |
+#ifdef CONFIG_UNEVICTABLE_LRU
+ 1 << PG_unevictable |
+#endif
1 << PG_dirty |
1 << PG_slab |
1 << PG_swapcache |
Index: linux-2.6.26-rc5-mm2/include/linux/mm_inline.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mm_inline.h 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mm_inline.h 2008-06-10 16:25:49.000000000 -0400
@@ -91,11 +91,16 @@ del_page_from_lru(struct zone *zone, str
enum lru_list l = LRU_BASE;
list_del(&page->lru);
- if (PageActive(page)) {
- __ClearPageActive(page);
- l += LRU_ACTIVE;
+ if (PageUnevictable(page)) {
+ __ClearPageUnevictable(page);
+ l = LRU_UNEVICTABLE;
+ } else {
+ if (PageActive(page)) {
+ __ClearPageActive(page);
+ l += LRU_ACTIVE;
+ }
+ l += page_is_file_cache(page);
}
- l += page_is_file_cache(page);
__dec_zone_state(zone, NR_LRU_BASE + l);
}
@@ -110,9 +115,13 @@ static inline enum lru_list page_lru(str
{
enum lru_list lru = LRU_BASE;
- if (PageActive(page))
- lru += LRU_ACTIVE;
- lru += page_is_file_cache(page);
+ if (PageUnevictable(page))
+ lru = LRU_UNEVICTABLE;
+ else {
+ if (PageActive(page))
+ lru += LRU_ACTIVE;
+ lru += page_is_file_cache(page);
+ }
return lru;
}
Index: linux-2.6.26-rc5-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/swap.h 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/swap.h 2008-06-10 22:11:01.000000000 -0400
@@ -180,6 +180,8 @@ extern int lru_add_drain_all(void);
extern void rotate_reclaimable_page(struct page *page);
extern void swap_setup(void);
+extern void add_page_to_unevictable_list(struct page *page);
+
/**
* lru_cache_add: add a page to the page lists
* @page: the page to add
@@ -228,6 +230,16 @@ static inline int zone_reclaim(struct zo
}
#endif
+#ifdef CONFIG_UNEVICTABLE_LRU
+extern int page_evictable(struct page *page, struct vm_area_struct *vma);
+#else
+static inline int page_evictable(struct page *page,
+ struct vm_area_struct *vma)
+{
+ return 1;
+}
+#endif
+
extern int kswapd_run(int nid);
#ifdef CONFIG_MMU
Index: linux-2.6.26-rc5-mm2/include/linux/pagevec.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/pagevec.h 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/pagevec.h 2008-06-10 16:25:49.000000000 -0400
@@ -101,7 +101,6 @@ static inline void __pagevec_lru_add_act
____pagevec_lru_add(pvec, LRU_ACTIVE_FILE);
}
-
static inline void pagevec_lru_add_file(struct pagevec *pvec)
{
if (pagevec_count(pvec))
Index: linux-2.6.26-rc5-mm2/mm/swap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap.c 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap.c 2008-06-10 22:11:01.000000000 -0400
@@ -136,7 +136,7 @@ static void pagevec_move_tail(struct pag
void rotate_reclaimable_page(struct page *page)
{
if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
- PageLRU(page)) {
+ !PageUnevictable(page) && PageLRU(page)) {
struct pagevec *pvec;
unsigned long flags;
@@ -157,7 +157,7 @@ void activate_page(struct page *page)
struct zone *zone = page_zone(page);
spin_lock_irq(&zone->lru_lock);
- if (PageLRU(page) && !PageActive(page)) {
+ if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
int file = page_is_file_cache(page);
int lru = LRU_BASE + file;
del_page_from_lru_list(zone, page, lru);
@@ -166,7 +166,7 @@ void activate_page(struct page *page)
lru += LRU_ACTIVE;
add_page_to_lru_list(zone, page, lru);
__count_vm_event(PGACTIVATE);
- mem_cgroup_move_lists(page, true);
+ mem_cgroup_move_lists(page, lru);
zone->recent_rotated[!!file]++;
zone->recent_scanned[!!file]++;
@@ -183,7 +183,8 @@ void activate_page(struct page *page)
*/
void mark_page_accessed(struct page *page)
{
- if (!PageActive(page) && PageReferenced(page) && PageLRU(page)) {
+ if (!PageActive(page) && !PageUnevictable(page) &&
+ PageReferenced(page) && PageLRU(page)) {
activate_page(page);
ClearPageReferenced(page);
} else if (!PageReferenced(page)) {
@@ -211,13 +212,38 @@ void __lru_cache_add(struct page *page,
void lru_cache_add_lru(struct page *page, enum lru_list lru)
{
if (PageActive(page)) {
+ VM_BUG_ON(PageUnevictable(page));
ClearPageActive(page);
+ } else if (PageUnevictable(page)) {
+ VM_BUG_ON(PageActive(page));
+ ClearPageUnevictable(page);
}
- VM_BUG_ON(PageLRU(page) || PageActive(page));
+ VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page));
__lru_cache_add(page, lru);
}
+/**
+ * add_page_to_unevictable_list - add a page to the unevictable list
+ * @page: the page to be added to the unevictable list
+ *
+ * Add page directly to its zone's unevictable list. To avoid races with
+ * tasks that might be making the page evictable, through eg. munlock,
+ * munmap or exit, while it's not on the lru, we want to add the page
+ * while it's locked or otherwise "invisible" to other tasks. This is
+ * difficult to do when using the pagevec cache, so bypass that.
+ */
+void add_page_to_unevictable_list(struct page *page)
+{
+ struct zone *zone = page_zone(page);
+
+ spin_lock_irq(&zone->lru_lock);
+ SetPageUnevictable(page);
+ SetPageLRU(page);
+ add_page_to_lru_list(zone, page, LRU_UNEVICTABLE);
+ spin_unlock_irq(&zone->lru_lock);
+}
+
/*
* Drain pages out of the cpu's pagevecs.
* Either "cpu" is the current CPU, and preemption has already been
@@ -315,6 +341,7 @@ void release_pages(struct page **pages,
if (PageLRU(page)) {
struct zone *pagezone = page_zone(page);
+
if (pagezone != zone) {
if (zone)
spin_unlock_irqrestore(&zone->lru_lock,
@@ -391,6 +418,7 @@ void ____pagevec_lru_add(struct pagevec
{
int i;
struct zone *zone = NULL;
+ VM_BUG_ON(is_unevictable_lru(lru));
for (i = 0; i < pagevec_count(pvec); i++) {
struct page *page = pvec->pages[i];
@@ -402,6 +430,8 @@ void ____pagevec_lru_add(struct pagevec
zone = pagezone;
spin_lock_irq(&zone->lru_lock);
}
+ VM_BUG_ON(PageActive(page));
+ VM_BUG_ON(PageUnevictable(page));
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);
if (is_active_lru(lru))
Index: linux-2.6.26-rc5-mm2/mm/migrate.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/migrate.c 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/migrate.c 2008-06-10 22:11:01.000000000 -0400
@@ -53,14 +53,9 @@ int migrate_prep(void)
return 0;
}
-static inline void move_to_lru(struct page *page)
-{
- lru_cache_add_lru(page, page_lru(page));
- put_page(page);
-}
-
/*
- * Add isolated pages on the list back to the LRU.
+ * Add isolated pages on the list back to the LRU under page lock
+ * to avoid leaking evictable pages back onto unevictable list.
*
* returns the number of pages put back.
*/
@@ -72,7 +67,9 @@ int putback_lru_pages(struct list_head *
list_for_each_entry_safe(page, page2, l, lru) {
list_del(&page->lru);
- move_to_lru(page);
+ lock_page(page);
+ if (putback_lru_page(page))
+ unlock_page(page);
count++;
}
return count;
@@ -338,8 +335,11 @@ static void migrate_page_copy(struct pag
SetPageReferenced(newpage);
if (PageUptodate(page))
SetPageUptodate(newpage);
- if (PageActive(page))
+ if (TestClearPageActive(page)) {
+ VM_BUG_ON(PageUnevictable(page));
SetPageActive(newpage);
+ } else
+ unevictable_migrate_page(newpage, page);
if (PageChecked(page))
SetPageChecked(newpage);
if (PageMappedToDisk(page))
@@ -368,7 +368,6 @@ static void migrate_page_copy(struct pag
mem_cgroup_uncharge_page(page);
}
#endif
- ClearPageActive(page);
ClearPagePrivate(page);
set_page_private(page, 0);
page->mapping = NULL;
@@ -547,10 +546,15 @@ static int fallback_migrate_page(struct
*
* The new page will have replaced the old page if this function
* is successful.
+ *
+ * Return value:
+ * < 0 - error code
+ * == 0 - success
*/
static int move_to_new_page(struct page *newpage, struct page *page)
{
struct address_space *mapping;
+ int unlock = 1;
int rc;
/*
@@ -585,10 +589,16 @@ static int move_to_new_page(struct page
if (!rc) {
remove_migration_ptes(page, newpage);
+ /*
+ * Put back on LRU while holding page locked to
+ * handle potential race with, e.g., munlock()
+ */
+ unlock = putback_lru_page(newpage);
} else
newpage->mapping = NULL;
- unlock_page(newpage);
+ if (unlock)
+ unlock_page(newpage);
return rc;
}
@@ -605,18 +615,19 @@ static int unmap_and_move(new_page_t get
struct page *newpage = get_new_page(page, private, &result);
int rcu_locked = 0;
int charge = 0;
+ int unlock = 1;
if (!newpage)
return -ENOMEM;
if (page_count(page) == 1)
/* page was freed from under us. So we are done. */
- goto move_newpage;
+ goto end_migration;
charge = mem_cgroup_prepare_migration(page, newpage);
if (charge == -ENOMEM) {
rc = -ENOMEM;
- goto move_newpage;
+ goto end_migration;
}
/* prepare cgroup just returns 0 or -ENOMEM */
BUG_ON(charge);
@@ -624,7 +635,7 @@ static int unmap_and_move(new_page_t get
rc = -EAGAIN;
if (TestSetPageLocked(page)) {
if (!force)
- goto move_newpage;
+ goto end_migration;
lock_page(page);
}
@@ -686,8 +697,6 @@ rcu_unlock:
unlock:
- unlock_page(page);
-
if (rc != -EAGAIN) {
/*
* A page that has been migrated has all references
@@ -696,17 +705,30 @@ unlock:
* restored.
*/
list_del(&page->lru);
- move_to_lru(page);
+ if (!page->mapping) {
+ VM_BUG_ON(page_count(page) != 1);
+ unlock_page(page);
+ put_page(page); /* just free the old page */
+ goto end_migration;
+ } else
+ unlock = putback_lru_page(page);
}
-move_newpage:
+ if (unlock)
+ unlock_page(page);
+
+end_migration:
if (!charge)
mem_cgroup_end_migration(newpage);
- /*
- * Move the new page to the LRU. If migration was not successful
- * then this will free the page.
- */
- move_to_lru(newpage);
+
+ if (!newpage->mapping) {
+ /*
+ * Migration failed or was never attempted.
+ * Free the newpage.
+ */
+ VM_BUG_ON(page_count(newpage) != 1);
+ put_page(newpage);
+ }
if (result) {
if (rc)
*result = rc;
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 22:11:01.000000000 -0400
@@ -452,6 +452,73 @@ cannot_free:
return 0;
}
+/**
+ * putback_lru_page - put previously isolated page onto appropriate LRU list
+ * @page: page to be put back to appropriate lru list
+ *
+ * Add previously isolated @page to appropriate LRU list.
+ * Page may still be unevictable for other reasons.
+ *
+ * lru_lock must not be held, interrupts must be enabled.
+ * Must be called with page locked.
+ *
+ * return 1 if page still locked [not truncated], else 0
+ */
+int putback_lru_page(struct page *page)
+{
+ int lru;
+ int ret = 1;
+
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(PageLRU(page));
+
+ lru = !!TestClearPageActive(page);
+ ClearPageUnevictable(page); /* for page_evictable() */
+
+ if (unlikely(!page->mapping)) {
+ /*
+ * page truncated. drop lock as put_page() will
+ * free the page.
+ */
+ VM_BUG_ON(page_count(page) != 1);
+ unlock_page(page);
+ ret = 0;
+ } else if (page_evictable(page, NULL)) {
+ /*
+ * For evictable pages, we can use the cache.
+ * In event of a race, worst case is we end up with an
+ * unevictable page on [in]active list.
+ * We know how to handle that.
+ */
+ lru += page_is_file_cache(page);
+ lru_cache_add_lru(page, lru);
+ mem_cgroup_move_lists(page, lru);
+ } else {
+ /*
+ * Put unevictable pages directly on zone's unevictable
+ * list.
+ */
+ add_page_to_unevictable_list(page);
+ mem_cgroup_move_lists(page, LRU_UNEVICTABLE);
+ }
+
+ put_page(page); /* drop ref from isolate */
+ return ret; /* ret => "page still locked" */
+}
+
+/*
+ * Cull page that shrink_*_list() has detected to be unevictable
+ * under page lock to close races with other tasks that might be making
+ * the page evictable. Avoid stranding an evictable page on the
+ * unevictable list.
+ */
+static void cull_unevictable_page(struct page *page)
+{
+ lock_page(page);
+ if (putback_lru_page(page))
+ unlock_page(page);
+}
+
/*
* shrink_page_list() returns the number of reclaimed pages
*/
@@ -485,6 +552,12 @@ static unsigned long shrink_page_list(st
sc->nr_scanned++;
+ if (unlikely(!page_evictable(page, NULL))) {
+ if (putback_lru_page(page))
+ unlock_page(page);
+ continue;
+ }
+
if (!sc->may_swap && page_mapped(page))
goto keep_locked;
@@ -584,7 +657,7 @@ static unsigned long shrink_page_list(st
* possible for a page to have PageDirty set, but it is actually
* clean (all its buffers are clean). This happens if the
* buffers were written out directly, with submit_bh(). ext3
- * will do this, as well as the blockdev mapping.
+ * will do this, as well as the blockdev mapping.
* try_to_release_page() will discover that cleanness and will
* drop the buffers and mark the page clean - it can be freed.
*
@@ -616,6 +689,7 @@ activate_locked:
/* Not a candidate for swapping, so reclaim swap space. */
if (PageSwapCache(page) && vm_swap_full())
remove_exclusive_swap_page_ref(page);
+ VM_BUG_ON(PageActive(page));
SetPageActive(page);
pgactivate++;
keep_locked:
@@ -665,6 +739,14 @@ int __isolate_lru_page(struct page *page
if (mode != ISOLATE_BOTH && (!page_is_file_cache(page) != !file))
return ret;
+ /*
+ * When this function is being called for lumpy reclaim, we
+ * initially look into all LRU pages, active, inactive and
+ * unevictable; only give shrink_page_list evictable pages.
+ */
+ if (PageUnevictable(page))
+ return ret;
+
ret = -EBUSY;
if (likely(get_page_unless_zero(page))) {
/*
@@ -776,7 +858,7 @@ static unsigned long isolate_lru_pages(u
/* else it is being freed elsewhere */
list_move(&cursor_page->lru, src);
default:
- break;
+ break; /* ! on LRU or wrong list */
}
}
}
@@ -836,8 +918,9 @@ static unsigned long clear_active_flags(
* Returns -EBUSY if the page was not on an LRU list.
*
* The returned page will have PageLRU() cleared. If it was found on
- * the active list, it will have PageActive set. That flag may need
- * to be cleared by the caller before letting the page go.
+ * the active list, it will have PageActive set. If it was found on
+ * the unevictable list, it will have the PageUnevictable bit set. That flag
+ * may need to be cleared by the caller before letting the page go.
*
* The vmstat statistic corresponding to the list on which the page was
* found will be decremented.
@@ -858,11 +941,10 @@ int isolate_lru_page(struct page *page)
spin_lock_irq(&zone->lru_lock);
if (PageLRU(page) && get_page_unless_zero(page)) {
- int lru = LRU_BASE;
+ int lru = page_lru(page);
ret = 0;
ClearPageLRU(page);
- lru += page_is_file_cache(page) + !!PageActive(page);
del_page_from_lru_list(zone, page, lru);
}
spin_unlock_irq(&zone->lru_lock);
@@ -974,11 +1056,20 @@ static unsigned long shrink_inactive_lis
* Put back any unfreeable pages.
*/
while (!list_empty(&page_list)) {
+ int lru;
page = lru_to_page(&page_list);
VM_BUG_ON(PageLRU(page));
- SetPageLRU(page);
list_del(&page->lru);
- add_page_to_lru_list(zone, page, page_lru(page));
+ if (unlikely(!page_evictable(page, NULL))) {
+ spin_unlock_irq(&zone->lru_lock);
+ cull_unevictable_page(page);
+ spin_lock_irq(&zone->lru_lock);
+ continue;
+ }
+ SetPageLRU(page);
+ lru = page_lru(page);
+ add_page_to_lru_list(zone, page, lru);
+ mem_cgroup_move_lists(page, lru);
if (PageActive(page) && scan_global_lru(sc)) {
int file = !!page_is_file_cache(page);
zone->recent_rotated[file]++;
@@ -1073,6 +1164,12 @@ static void shrink_active_list(unsigned
cond_resched();
page = lru_to_page(&l_hold);
list_del(&page->lru);
+
+ if (unlikely(!page_evictable(page, NULL))) {
+ cull_unevictable_page(page);
+ continue;
+ }
+
if (page_referenced(page, 0, sc->mem_cgroup)) {
pgmoved++;
if (file) {
@@ -1118,7 +1215,7 @@ static void shrink_active_list(unsigned
ClearPageActive(page);
list_move(&page->lru, &zone->lru[lru].list);
- mem_cgroup_move_lists(page, false);
+ mem_cgroup_move_lists(page, lru);
pgmoved++;
if (!pagevec_add(&pvec, page)) {
__mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
@@ -1149,7 +1246,7 @@ static void shrink_active_list(unsigned
VM_BUG_ON(!PageActive(page));
list_move(&page->lru, &zone->lru[lru].list);
- mem_cgroup_move_lists(page, true);
+ mem_cgroup_move_lists(page, lru);
pgmoved++;
if (!pagevec_add(&pvec, page)) {
__mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
@@ -1289,7 +1386,7 @@ static unsigned long shrink_zone(int pri
get_scan_ratio(zone, sc, percent);
- for_each_lru(l) {
+ for_each_evictable_lru(l) {
if (scan_global_lru(sc)) {
int file = is_file_lru(l);
int scan;
@@ -1319,7 +1416,7 @@ static unsigned long shrink_zone(int pri
while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
nr[LRU_INACTIVE_FILE]) {
- for_each_lru(l) {
+ for_each_evictable_lru(l) {
if (nr[l]) {
nr_to_scan = min(nr[l],
(unsigned long)sc->swap_cluster_max);
@@ -1874,8 +1971,8 @@ static unsigned long shrink_all_zones(un
if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY)
continue;
- for_each_lru(l) {
- /* For pass = 0 we don't shrink the active list */
+ for_each_evictable_lru(l) {
+ /* For pass = 0, we don't shrink the active list */
if (pass == 0 &&
(l == LRU_ACTIVE || l == LRU_ACTIVE_FILE))
continue;
@@ -2212,3 +2309,26 @@ int zone_reclaim(struct zone *zone, gfp_
return ret;
}
#endif
+
+#ifdef CONFIG_UNEVICTABLE_LRU
+/*
+ * page_evictable - test whether a page is evictable
+ * @page: the page to test
+ * @vma: the VMA in which the page is or will be mapped, may be NULL
+ *
+ * Test whether page is evictable--i.e., should be placed on active/inactive
+ * lists vs unevictable list.
+ *
+ * Reasons page might not be evictable:
+ * TODO - later patches
+ */
+int page_evictable(struct page *page, struct vm_area_struct *vma)
+{
+
+ VM_BUG_ON(PageUnevictable(page));
+
+ /* TODO: test page [!]evictable conditions */
+
+ return 1;
+}
+#endif
Index: linux-2.6.26-rc5-mm2/mm/mempolicy.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mempolicy.c 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mempolicy.c 2008-06-10 16:25:49.000000000 -0400
@@ -2199,7 +2199,7 @@ static void gather_stats(struct page *pa
if (PageSwapCache(page))
md->swapcache++;
- if (PageActive(page))
+ if (PageActive(page) || PageUnevictable(page))
md->active++;
if (PageWriteback(page))
Index: linux-2.6.26-rc5-mm2/mm/internal.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/internal.h 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/internal.h 2008-06-10 22:11:01.000000000 -0400
@@ -39,8 +39,15 @@ static inline void __put_page(struct pag
atomic_dec(&page->_count);
}
+/*
+ * in mm/vmscan.c:
+ */
extern int isolate_lru_page(struct page *page);
+extern int putback_lru_page(struct page *page);
+/*
+ * in mm/page_alloc.c
+ */
extern void __free_pages_bootmem(struct page *page, unsigned int order);
/*
@@ -54,6 +61,25 @@ static inline unsigned long page_order(s
return page_private(page);
}
+#ifdef CONFIG_UNEVICTABLE_LRU
+/*
+ * unevictable_migrate_page() called only from migrate_page_copy() to
+ * migrate unevictable flag to new page.
+ * Note that the old page has been isolated from the LRU lists at this
+ * point so we don't need to worry about LRU statistics.
+ */
+static inline void unevictable_migrate_page(struct page *new, struct page *old)
+{
+ if (TestClearPageUnevictable(old))
+ SetPageUnevictable(new);
+}
+#else
+static inline void unevictable_migrate_page(struct page *new, struct page *old)
+{
+}
+#endif
+
+
/*
* FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
* so all functions starting at paging_init should be marked __init
Index: linux-2.6.26-rc5-mm2/mm/memcontrol.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memcontrol.c 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memcontrol.c 2008-06-10 22:11:01.000000000 -0400
@@ -160,9 +160,10 @@ struct page_cgroup {
struct mem_cgroup *mem_cgroup;
int flags;
};
-#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
-#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
-#define PAGE_CGROUP_FLAG_FILE (0x4) /* page is file system backed */
+#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
+#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
+#define PAGE_CGROUP_FLAG_FILE (0x4) /* page is file system backed */
+#define PAGE_CGROUP_FLAG_UNEVICTABLE (0x8) /* page is unevictableable */
static int page_cgroup_nid(struct page_cgroup *pc)
{
@@ -283,10 +284,14 @@ static void __mem_cgroup_remove_list(str
{
int lru = LRU_BASE;
- if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
- lru += LRU_ACTIVE;
- if (pc->flags & PAGE_CGROUP_FLAG_FILE)
- lru += LRU_FILE;
+ if (pc->flags & PAGE_CGROUP_FLAG_UNEVICTABLE)
+ lru = LRU_UNEVICTABLE;
+ else {
+ if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
+ lru += LRU_ACTIVE;
+ if (pc->flags & PAGE_CGROUP_FLAG_FILE)
+ lru += LRU_FILE;
+ }
MEM_CGROUP_ZSTAT(mz, lru) -= 1;
@@ -299,10 +304,14 @@ static void __mem_cgroup_add_list(struct
{
int lru = LRU_BASE;
- if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
- lru += LRU_ACTIVE;
- if (pc->flags & PAGE_CGROUP_FLAG_FILE)
- lru += LRU_FILE;
+ if (pc->flags & PAGE_CGROUP_FLAG_UNEVICTABLE)
+ lru = LRU_UNEVICTABLE;
+ else {
+ if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
+ lru += LRU_ACTIVE;
+ if (pc->flags & PAGE_CGROUP_FLAG_FILE)
+ lru += LRU_FILE;
+ }
MEM_CGROUP_ZSTAT(mz, lru) += 1;
list_add(&pc->lru, &mz->lists[lru]);
@@ -310,21 +319,31 @@ static void __mem_cgroup_add_list(struct
mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true);
}
-static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
+static void __mem_cgroup_move_lists(struct page_cgroup *pc, enum lru_list lru)
{
struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
- int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
- int file = pc->flags & PAGE_CGROUP_FLAG_FILE;
- int lru = LRU_FILE * !!file + !!from;
+ int active = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
+ int file = pc->flags & PAGE_CGROUP_FLAG_FILE;
+ int unevictable = pc->flags & PAGE_CGROUP_FLAG_UNEVICTABLE;
+ enum lru_list from = unevictable ? LRU_UNEVICTABLE :
+ (LRU_FILE * !!file + !!active);
- MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+ if (lru == from)
+ return;
- if (active)
- pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
- else
+ MEM_CGROUP_ZSTAT(mz, from) -= 1;
+
+ if (is_unevictable_lru(lru)) {
pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
+ pc->flags |= PAGE_CGROUP_FLAG_UNEVICTABLE;
+ } else {
+ if (is_active_lru(lru))
+ pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
+ else
+ pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
+ pc->flags &= ~PAGE_CGROUP_FLAG_UNEVICTABLE;
+ }
- lru = LRU_FILE * !!file + !!active;
MEM_CGROUP_ZSTAT(mz, lru) += 1;
list_move(&pc->lru, &mz->lists[lru]);
}
@@ -342,7 +361,7 @@ int task_in_mem_cgroup(struct task_struc
/*
* This routine assumes that the appropriate zone's lru lock is already held
*/
-void mem_cgroup_move_lists(struct page *page, bool active)
+void mem_cgroup_move_lists(struct page *page, enum lru_list lru)
{
struct page_cgroup *pc;
struct mem_cgroup_per_zone *mz;
@@ -362,7 +381,7 @@ void mem_cgroup_move_lists(struct page *
if (pc) {
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_move_lists(pc, active);
+ __mem_cgroup_move_lists(pc, lru);
spin_unlock_irqrestore(&mz->lru_lock, flags);
}
unlock_page_cgroup(page);
@@ -460,12 +479,10 @@ unsigned long mem_cgroup_isolate_pages(u
/*
* TODO: play better with lumpy reclaim, grabbing anything.
*/
- if (PageActive(page) && !active) {
- __mem_cgroup_move_lists(pc, true);
- continue;
- }
- if (!PageActive(page) && active) {
- __mem_cgroup_move_lists(pc, false);
+ if (PageUnevictable(page) ||
+ (PageActive(page) && !active) ||
+ (!PageActive(page) && active)) {
+ __mem_cgroup_move_lists(pc, page_lru(page));
continue;
}
Index: linux-2.6.26-rc5-mm2/include/linux/memcontrol.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/memcontrol.h 2008-06-10 16:23:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/memcontrol.h 2008-06-10 22:11:08.000000000 -0400
@@ -34,9 +34,9 @@ extern int mem_cgroup_charge(struct page
gfp_t gfp_mask);
extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
+extern void mem_cgroup_move_lists(struct page *page, enum lru_list lru);
extern void mem_cgroup_uncharge_page(struct page *page);
extern void mem_cgroup_uncharge_cache_page(struct page *page);
-extern void mem_cgroup_move_lists(struct page *page, bool active);
extern int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask);
extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 13/24] Unevictable LRU Page Statistics
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (11 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 12/24] Unevictable LRU Infrastructure Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable Rik van Riel
` (11 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-noreclaim-lru-page-statistics.patch --]
[-- Type: text/plain, Size: 5855 bytes --]
From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Report unevictable pages per zone and system wide.
Kosaki Motohiro added support for memory controller unevictable
statistics.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
drivers/base/node.c | 6 ++++++
fs/proc/proc_misc.c | 6 ++++++
mm/memcontrol.c | 6 ++++++
mm/page_alloc.c | 16 +++++++++++++++-
mm/vmstat.c | 3 +++
5 files changed, 36 insertions(+), 1 deletion(-)
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 22:13:37.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 22:36:56.000000000 -0400
@@ -1844,12 +1844,20 @@ void show_free_areas(void)
}
printk("Active_anon:%lu active_file:%lu inactive_anon%lu\n"
- " inactive_file:%lu dirty:%lu writeback:%lu unstable:%lu\n"
+ " inactive_file:%lu"
+//TODO: check/adjust line lengths
+#ifdef CONFIG_UNEVICTABLE_LRU
+ " unevictable:%lu"
+#endif
+ " dirty:%lu writeback:%lu unstable:%lu\n"
" free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
global_page_state(NR_ACTIVE_ANON),
global_page_state(NR_ACTIVE_FILE),
global_page_state(NR_INACTIVE_ANON),
global_page_state(NR_INACTIVE_FILE),
+#ifdef CONFIG_UNEVICTABLE_LRU
+ global_page_state(NR_UNEVICTABLE),
+#endif
global_page_state(NR_FILE_DIRTY),
global_page_state(NR_WRITEBACK),
global_page_state(NR_UNSTABLE_NFS),
@@ -1876,6 +1884,9 @@ void show_free_areas(void)
" inactive_anon:%lukB"
" active_file:%lukB"
" inactive_file:%lukB"
+#ifdef CONFIG_UNEVICTABLE_LRU
+ " unevictable:%lukB"
+#endif
" present:%lukB"
" pages_scanned:%lu"
" all_unreclaimable? %s"
@@ -1889,6 +1900,9 @@ void show_free_areas(void)
K(zone_page_state(zone, NR_INACTIVE_ANON)),
K(zone_page_state(zone, NR_ACTIVE_FILE)),
K(zone_page_state(zone, NR_INACTIVE_FILE)),
+#ifdef CONFIG_UNEVICTABLE_LRU
+ K(zone_page_state(zone, NR_UNEVICTABLE)),
+#endif
K(zone->present_pages),
zone->pages_scanned,
(zone_is_all_unreclaimable(zone) ? "yes" : "no")
Index: linux-2.6.26-rc5-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmstat.c 2008-06-10 22:13:33.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmstat.c 2008-06-10 22:36:56.000000000 -0400
@@ -606,6 +606,9 @@ static const char * const vmstat_text[]
"nr_active_anon",
"nr_inactive_file",
"nr_active_file",
+#ifdef CONFIG_UNEVICTABLE_LRU
+ "nr_unevictable",
+#endif
"nr_anon_pages",
"nr_mapped",
"nr_file_pages",
Index: linux-2.6.26-rc5-mm2/drivers/base/node.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/drivers/base/node.c 2008-06-10 22:13:33.000000000 -0400
+++ linux-2.6.26-rc5-mm2/drivers/base/node.c 2008-06-10 22:37:14.000000000 -0400
@@ -67,6 +67,9 @@ static ssize_t node_read_meminfo(struct
"Node %d Inactive(anon): %8lu kB\n"
"Node %d Active(file): %8lu kB\n"
"Node %d Inactive(file): %8lu kB\n"
+#ifdef CONFIG_UNEVICTABLE_LRU
+ "Node %d Noreclaim: %8lu kB\n"
+#endif
#ifdef CONFIG_HIGHMEM
"Node %d HighTotal: %8lu kB\n"
"Node %d HighFree: %8lu kB\n"
@@ -96,6 +99,9 @@ static ssize_t node_read_meminfo(struct
nid, node_page_state(nid, NR_INACTIVE_ANON),
nid, node_page_state(nid, NR_ACTIVE_FILE),
nid, node_page_state(nid, NR_INACTIVE_FILE),
+#ifdef CONFIG_UNEVICTABLE_LRU
+ nid, node_page_state(nid, NR_UNEVICTABLE),
+#endif
#ifdef CONFIG_HIGHMEM
nid, K(i.totalhigh),
nid, K(i.freehigh),
Index: linux-2.6.26-rc5-mm2/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/proc/proc_misc.c 2008-06-10 22:13:33.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/proc/proc_misc.c 2008-06-10 22:36:56.000000000 -0400
@@ -175,6 +175,9 @@ static int meminfo_read_proc(char *page,
"Inactive(anon): %8lu kB\n"
"Active(file): %8lu kB\n"
"Inactive(file): %8lu kB\n"
+#ifdef CONFIG_UNEVICTABLE_LRU
+ "Unevictable: %8lu kB\n"
+#endif
#ifdef CONFIG_HIGHMEM
"HighTotal: %8lu kB\n"
"HighFree: %8lu kB\n"
@@ -210,6 +213,9 @@ static int meminfo_read_proc(char *page,
K(pages[LRU_INACTIVE_ANON]),
K(pages[LRU_ACTIVE_FILE]),
K(pages[LRU_INACTIVE_FILE]),
+#ifdef CONFIG_UNEVICTABLE_LRU
+ K(pages[LRU_UNEVICTABLE]),
+#endif
#ifdef CONFIG_HIGHMEM
K(i.totalhigh),
K(i.freehigh),
Index: linux-2.6.26-rc5-mm2/mm/memcontrol.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memcontrol.c 2008-06-10 22:13:37.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memcontrol.c 2008-06-10 22:13:38.000000000 -0400
@@ -930,6 +930,7 @@ static int mem_control_stat_show(struct
{
unsigned long active_anon, inactive_anon;
unsigned long active_file, inactive_file;
+ unsigned long unevictable;
inactive_anon = mem_cgroup_get_all_zonestat(mem_cont,
LRU_INACTIVE_ANON);
@@ -939,10 +940,15 @@ static int mem_control_stat_show(struct
LRU_INACTIVE_FILE);
active_file = mem_cgroup_get_all_zonestat(mem_cont,
LRU_ACTIVE_FILE);
+ unevictable = mem_cgroup_get_all_zonestat(mem_cont,
+ LRU_UNEVICTABLE);
+
cb->fill(cb, "active_anon", (active_anon) * PAGE_SIZE);
cb->fill(cb, "inactive_anon", (inactive_anon) * PAGE_SIZE);
cb->fill(cb, "active_file", (active_file) * PAGE_SIZE);
cb->fill(cb, "inactive_file", (inactive_file) * PAGE_SIZE);
+ cb->fill(cb, "unevictable", unevictable * PAGE_SIZE);
+
}
return 0;
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (12 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 13/24] Unevictable LRU Page Statistics Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-12 0:54 ` Nick Piggin
2008-06-11 18:42 ` [PATCH -mm 15/24] SHM_LOCKED " Rik van Riel
` (10 subsequent siblings)
24 siblings, 1 reply; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, linux-mm, Eric Whitney
[-- Attachment #1: vmscan-ramfs-and-ram-disk-pages-are-non-reclaimable.patch --]
[-- Type: text/plain, Size: 4640 bytes --]
From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Christoph Lameter pointed out that ram disk pages also clutter the
LRU lists. When vmscan finds them dirty and tries to clean them,
the ram disk writeback function just redirties the page so that it
goes back onto the active list. Round and round she goes...
Define new address_space flag [shares address_space flags member
with mapping's gfp mask] to indicate that the address space contains
all unevictable pages. This will provide for efficient testing
of ramdisk pages in page_evictable().
Also provide wrapper functions to set/test the unevictable state to
minimize #ifdefs in ramdisk driver and any other users of this
facility.
Set the unevictable state on address_space structures for new
ramdisk inodes. Test the unevictable state in page_evictable()
to cull unevictable pages.
Similarly, ramfs pages are unevictable. Set the 'unevictable'
address_space flag for new ramfs inodes.
These changes depend on [CONFIG_]UNEVICTABLE_LRU.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
drivers/block/brd.c | 13 +++++++++++++
fs/ramfs/inode.c | 1 +
include/linux/pagemap.h | 22 ++++++++++++++++++++++
mm/vmscan.c | 5 +++++
4 files changed, 41 insertions(+)
Index: linux-2.6.26-rc5-mm2/include/linux/pagemap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/pagemap.h 2008-06-10 10:46:23.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/pagemap.h 2008-06-10 16:47:23.000000000 -0400
@@ -30,6 +30,28 @@ static inline void mapping_set_error(str
}
}
+#ifdef CONFIG_UNEVICTABLE_LRU
+#define AS_UNEVICTABLE (__GFP_BITS_SHIFT + 2) /* e.g., ramdisk, SHM_LOCK */
+
+static inline void mapping_set_unevictable(struct address_space *mapping)
+{
+ set_bit(AS_UNEVICTABLE, &mapping->flags);
+}
+
+static inline int mapping_unevictable(struct address_space *mapping)
+{
+ if (mapping && (mapping->flags & AS_UNEVICTABLE))
+ return 1;
+ return 0;
+}
+#else
+static inline void mapping_set_unevictable(struct address_space *mapping) { }
+static inline int mapping_unevictable(struct address_space *mapping)
+{
+ return 0;
+}
+#endif
+
static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
{
return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 16:25:49.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 16:47:23.000000000 -0400
@@ -2320,6 +2320,8 @@ int zone_reclaim(struct zone *zone, gfp_
* lists vs unevictable list.
*
* Reasons page might not be evictable:
+ * (1) page's mapping marked unevictable
+ *
* TODO - later patches
*/
int page_evictable(struct page *page, struct vm_area_struct *vma)
@@ -2327,6 +2329,9 @@ int page_evictable(struct page *page, st
VM_BUG_ON(PageUnevictable(page));
+ if (mapping_unevictable(page_mapping(page)))
+ return 0;
+
/* TODO: test page [!]evictable conditions */
return 1;
Index: linux-2.6.26-rc5-mm2/fs/ramfs/inode.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/ramfs/inode.c 2008-06-10 10:25:06.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/ramfs/inode.c 2008-06-10 16:47:23.000000000 -0400
@@ -61,6 +61,7 @@ struct inode *ramfs_get_inode(struct sup
inode->i_mapping->a_ops = &ramfs_aops;
inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;
mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
+ mapping_set_unevictable(inode->i_mapping);
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch (mode & S_IFMT) {
default:
Index: linux-2.6.26-rc5-mm2/drivers/block/brd.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/drivers/block/brd.c 2008-06-10 10:46:18.000000000 -0400
+++ linux-2.6.26-rc5-mm2/drivers/block/brd.c 2008-06-10 16:47:23.000000000 -0400
@@ -374,8 +374,21 @@ static int brd_ioctl(struct inode *inode
return error;
}
+/*
+ * brd_open():
+ * Just mark the mapping as containing unevictable pages
+ */
+static int brd_open(struct inode *inode, struct file *filp)
+{
+ struct address_space *mapping = inode->i_mapping;
+
+ mapping_set_unevictable(mapping);
+ return 0;
+}
+
static struct block_device_operations brd_fops = {
.owner = THIS_MODULE,
+ .open = brd_open,
.ioctl = brd_ioctl,
#ifdef CONFIG_BLK_DEV_XIP
.direct_access = brd_direct_access,
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 15/24] SHM_LOCKED pages are unevictable
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (13 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 16/24] mlock: mlocked " Rik van Riel
` (9 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-shm_locked-pages-are-non-reclaimable.patch --]
[-- Type: text/plain, Size: 10197 bytes --]
From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Shmem segments locked into memory via shmctl(SHM_LOCKED) should
not be kept on the normal LRU, since scanning them is a waste of
time and might throw off kswapd's balancing algorithms. Place
them on the unevictable LRU list instead.
Use the AS_UNEVICTABLE flag to mark address_space of SHM_LOCKed
shared memory regions as unevictable. Then these pages
will be culled off the normal LRU lists during vmscan.
Add new wrapper function to clear the mapping's unevictable state
when/if shared memory segment is munlocked.
Add 'scan_mapping_unevictable_page()' to mm/vmscan.c to scan all
pages in the shmem segment's mapping [struct address_space] for
evictability now that they're no longer locked. If so, move
them to the appropriate zone lru list. Note that
scan_mapping_unevictable_page() must be able to sleep on page_lock(),
so we can't call it holding the shmem info spinlock nor the shmid
spinlock. So, we pass the mapping [address_space] back to shmctl()
on SHM_UNLOCK for rescuing any unevictable pages after dropping
the spinlocks. Once we drop the shmid lock, the backing shmem file
can be deleted if the calling task doesn't have the shm area
attached. To handle this, we take an extra reference on the file
before dropping the shmid lock and drop the reference after scanning
the mapping's unevictable pages.
Changes depend on [CONFIG_]UNEVICTABLE_LRU.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
include/linux/mm.h | 9 ++--
include/linux/pagemap.h | 12 ++++--
include/linux/swap.h | 4 ++
ipc/shm.c | 20 +++++++++-
mm/shmem.c | 10 +++--
mm/vmscan.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 136 insertions(+), 12 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/shmem.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/shmem.c 2008-06-10 22:13:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/shmem.c 2008-06-10 22:13:39.000000000 -0400
@@ -1473,23 +1473,27 @@ static struct mempolicy *shmem_get_polic
}
#endif
-int shmem_lock(struct file *file, int lock, struct user_struct *user)
+struct address_space *shmem_lock(struct file *file, int lock,
+ struct user_struct *user)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct shmem_inode_info *info = SHMEM_I(inode);
- int retval = -ENOMEM;
+ struct address_space *retval = ERR_PTR(-ENOMEM);
spin_lock(&info->lock);
if (lock && !(info->flags & VM_LOCKED)) {
if (!user_shm_lock(inode->i_size, user))
goto out_nomem;
info->flags |= VM_LOCKED;
+ mapping_set_unevictable(file->f_mapping);
+ retval = NULL;
}
if (!lock && (info->flags & VM_LOCKED) && user) {
user_shm_unlock(inode->i_size, user);
info->flags &= ~VM_LOCKED;
+ mapping_clear_unevictable(file->f_mapping);
+ retval = file->f_mapping;
}
- retval = 0;
out_nomem:
spin_unlock(&info->lock);
return retval;
Index: linux-2.6.26-rc5-mm2/include/linux/pagemap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/pagemap.h 2008-06-10 22:13:38.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/pagemap.h 2008-06-10 22:13:39.000000000 -0400
@@ -38,14 +38,20 @@ static inline void mapping_set_unevictab
set_bit(AS_UNEVICTABLE, &mapping->flags);
}
+static inline void mapping_clear_unevictable(struct address_space *mapping)
+{
+ clear_bit(AS_UNEVICTABLE, &mapping->flags);
+}
+
static inline int mapping_unevictable(struct address_space *mapping)
{
- if (mapping && (mapping->flags & AS_UNEVICTABLE))
- return 1;
- return 0;
+ if (likely(mapping))
+ return test_bit(AS_UNEVICTABLE, &mapping->flags);
+ return !!mapping;
}
#else
static inline void mapping_set_unevictable(struct address_space *mapping) { }
+static inline void mapping_clear_unevictable(struct address_space *mapping) { }
static inline int mapping_unevictable(struct address_space *mapping)
{
return 0;
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 22:13:38.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 22:19:32.000000000 -0400
@@ -2336,4 +2336,97 @@ int page_evictable(struct page *page, st
return 1;
}
+
+/**
+ * check_move_unevictable_page - check page for evictability and move to appropriate zone lru list
+ * @page: page to check evictability and move to appropriate lru list
+ * @zone: zone page is in
+ *
+ * Checks a page for evictability and moves the page to the appropriate
+ * zone lru list.
+ *
+ * Restrictions: zone->lru_lock must be held, page must be on LRU and must
+ * have PageUnevictable set.
+ */
+static void check_move_unevictable_page(struct page *page, struct zone *zone)
+{
+
+ ClearPageUnevictable(page); /* for page_evictable() */
+ if (page_evictable(page, NULL)) {
+ enum lru_list l = LRU_INACTIVE_ANON + page_is_file_cache(page);
+ __dec_zone_state(zone, NR_UNEVICTABLE);
+ list_move(&page->lru, &zone->lru[l].list);
+ __inc_zone_state(zone, NR_INACTIVE_ANON + l);
+ } else {
+ /*
+ * rotate unevictable list
+ */
+ SetPageUnevictable(page);
+ list_move(&page->lru, &zone->lru[LRU_UNEVICTABLE].list);
+ }
+}
+
+/**
+ * scan_mapping_unevictable_pages - scan an address space for evictable pages
+ * @mapping: struct address_space to scan for evictable pages
+ *
+ * Scan all pages in mapping. Check unevictable pages for
+ * evictability and move them to the appropriate zone lru list.
+ */
+void scan_mapping_unevictable_pages(struct address_space *mapping)
+{
+ pgoff_t next = 0;
+ pgoff_t end = (i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT;
+ struct zone *zone;
+ struct pagevec pvec;
+
+ if (mapping->nrpages == 0)
+ return;
+
+ pagevec_init(&pvec, 0);
+ while (next < end &&
+ pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
+ int i;
+
+ zone = NULL;
+
+ for (i = 0; i < pagevec_count(&pvec); i++) {
+ struct page *page = pvec.pages[i];
+ pgoff_t page_index = page->index;
+ struct zone *pagezone = page_zone(page);
+
+ if (page_index > next)
+ next = page_index;
+ next++;
+
+ if (TestSetPageLocked(page)) {
+ /*
+ * OK, let's do it the hard way...
+ */
+ if (zone)
+ spin_unlock_irq(&zone->lru_lock);
+ zone = NULL;
+ lock_page(page);
+ }
+
+ if (pagezone != zone) {
+ if (zone)
+ spin_unlock_irq(&zone->lru_lock);
+ zone = pagezone;
+ spin_lock_irq(&zone->lru_lock);
+ }
+
+ if (PageLRU(page) && PageUnevictable(page))
+ check_move_unevictable_page(page, zone);
+
+ unlock_page(page);
+
+ }
+ if (zone)
+ spin_unlock_irq(&zone->lru_lock);
+ pagevec_release(&pvec);
+ }
+
+}
#endif
Index: linux-2.6.26-rc5-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/swap.h 2008-06-10 22:13:37.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/swap.h 2008-06-10 22:18:03.000000000 -0400
@@ -232,12 +232,16 @@ static inline int zone_reclaim(struct zo
#ifdef CONFIG_UNEVICTABLE_LRU
extern int page_evictable(struct page *page, struct vm_area_struct *vma);
+extern void scan_mapping_unevictable_pages(struct address_space *);
#else
static inline int page_evictable(struct page *page,
struct vm_area_struct *vma)
{
return 1;
}
+static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
+{
+}
#endif
extern int kswapd_run(int nid);
Index: linux-2.6.26-rc5-mm2/include/linux/mm.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mm.h 2008-06-10 22:13:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mm.h 2008-06-10 22:18:03.000000000 -0400
@@ -701,12 +701,13 @@ static inline int page_mapped(struct pag
extern void show_free_areas(void);
#ifdef CONFIG_SHMEM
-int shmem_lock(struct file *file, int lock, struct user_struct *user);
+extern struct address_space *shmem_lock(struct file *file, int lock,
+ struct user_struct *user);
#else
-static inline int shmem_lock(struct file *file, int lock,
- struct user_struct *user)
+static inline struct address_space *shmem_lock(struct file *file, int lock,
+ struct user_struct *user)
{
- return 0;
+ return NULL;
}
#endif
struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags);
Index: linux-2.6.26-rc5-mm2/ipc/shm.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/ipc/shm.c 2008-06-10 22:13:31.000000000 -0400
+++ linux-2.6.26-rc5-mm2/ipc/shm.c 2008-06-10 22:13:39.000000000 -0400
@@ -737,6 +737,11 @@ asmlinkage long sys_shmctl(int shmid, in
case SHM_LOCK:
case SHM_UNLOCK:
{
+ struct address_space *mapping = NULL;
+ struct file *uninitialized_var(shm_file);
+
+ lru_add_drain_all(); /* drain pagevecs to lru lists */
+
shp = shm_lock_check(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
@@ -764,18 +769,29 @@ asmlinkage long sys_shmctl(int shmid, in
if(cmd==SHM_LOCK) {
struct user_struct * user = current->user;
if (!is_file_hugepages(shp->shm_file)) {
- err = shmem_lock(shp->shm_file, 1, user);
+ mapping = shmem_lock(shp->shm_file, 1, user);
+ if (IS_ERR(mapping))
+ err = PTR_ERR(mapping);
+ mapping = NULL;
if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
shp->shm_perm.mode |= SHM_LOCKED;
shp->mlock_user = user;
}
}
} else if (!is_file_hugepages(shp->shm_file)) {
- shmem_lock(shp->shm_file, 0, shp->mlock_user);
+ mapping = shmem_lock(shp->shm_file, 0, shp->mlock_user);
shp->shm_perm.mode &= ~SHM_LOCKED;
shp->mlock_user = NULL;
+ if (mapping) {
+ shm_file = shp->shm_file;
+ get_file(shm_file); /* hold across unlock */
+ }
}
shm_unlock(shp);
+ if (mapping) {
+ scan_mapping_unevictable_pages(mapping);
+ fput(shm_file);
+ }
goto out;
}
case IPC_RMID:
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 16/24] mlock: mlocked pages are unevictable
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (14 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 15/24] SHM_LOCKED " Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 17/24] mlock: downgrade mmap sem while populating mlocked regions Rik van Riel
` (8 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, linux-mm,
Eric Whitney, Nick Piggin
[-- Attachment #1: vmscan-mlocked-pages-are-non-reclaimable.patch --]
[-- Type: text/plain, Size: 44143 bytes --]
From: Nick Piggin <npiggin@suse.de>
Make sure that mlocked pages also live on the unevictable
LRU, so kswapd will not scan them over and over again.
This is achieved through various strategies:
1) add yet another page flag--PG_mlocked--to indicate that
the page is locked for efficient testing in vmscan and,
optionally, fault path. This allows early culling of
unevictable pages, preventing them from getting to
page_referenced()/try_to_unmap(). Also allows separate
accounting of mlock'd pages, as Nick's original patch
did.
Note: Nick's original mlock patch used a PG_mlocked
flag. I had removed this in favor of the PG_unevictable
flag + an mlock_count [new page struct member]. I
restored the PG_mlocked flag to eliminate the new
count field.
2) add the mlock/unevictable infrastructure to mm/mlock.c,
with internal APIs in mm/internal.h. This is a rework
of Nick's original patch to these files, taking into
account that mlocked pages are now kept on unevictable
LRU list.
3) update vmscan.c:page_evictable() to check PageMlocked()
and, if vma passed in, the vm_flags. Note that the vma
will only be passed in for new pages in the fault path;
and then only if the "cull unevictable pages in fault
path" patch is included.
4) add try_to_unlock() to rmap.c to walk a page's rmap and
ClearPageMlocked() if no other vmas have it mlocked.
Reuses as much of try_to_unmap() as possible. This
effectively replaces the use of one of the lru list links
as an mlock count. If this mechanism let's pages in mlocked
vmas leak through w/o PG_mlocked set [I don't know that it
does], we should catch them later in try_to_unmap(). One
hopes this will be rare, as it will be relatively expensive.
5) Kosaki: added munlock page table walk to avoid using
get_user_pages() for unlock. get_user_pages() is unreliable
for some vma protections.
Lee: modified to wait for in-flight migration to complete
to close munlock/migration race that could strand pages.
Original mm/internal.h, mm/rmap.c and mm/mlock.c changes:
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
---
V8:
+ more refinement of rmap interaction, including attempt to
handle mlocked pages in non-linear mappings.
+ cleanup of lockdep reported errors.
+ enhancement of munlock page table walker to detect and
handle pages under migration [migration ptes].
V6:
+ Kosaki-san and Rik van Riel: added check for "page mapped
in vma" to try_to_unlock() processing in try_to_unmap_anon().
+ Kosaki-san added munlock page table walker to avoid use of
get_user_pages() for munlock. get_user_pages() proved to be
unreliable for some types of vmas.
+ added filtering of "special" vmas. Some [_IO||_PFN] we skip
altogether. Others, we just "make_pages_present" to simulate
old behavior--i.e., populate page tables. Clear/don't set
VM_LOCKED in non-mlockable vmas so that we don't try to unlock
at exit/unmap time.
+ rework PG_mlock page flag definitions for new page flags
macros.
+ Clear PageMlocked when COWing a page into a VM_LOCKED vma
so we don't leave an mlocked page in another non-mlocked
vma. If the other vma[s] had the page mlocked, we'll re-mlock
it if/when we try to reclaim it. This is less expensive than
walking the rmap in the COW/fault path.
+ in vmscan:shrink_page_list(), avoid adding anon page to
the swap cache if it's in a VM_LOCKED vma, even tho'
PG_mlocked might not be set. Call try_to_unlock() to
determine this. As a result, we'll never try to unmap
an mlocked anon page.
+ in support of the above change, updated try_to_unlock()
to use same logic as try_to_unmap() when it encounters a
VM_LOCKED vma--call mlock_vma_page() directly. Added
stub try_to_unlock() for vmscan when NORECLAIM_MLOCK
not configured.
V4 -> V5:
+ fixed problem with placement of #ifdef CONFIG_NORECLAIM_MLOCK
in prep_new_page() [Thanks, minchan Kim!].
V3 -> V4:
+ Added #ifdef CONFIG_NORECLAIM_MLOCK, #endif around use of
PG_mlocked in free_page_check(), et al. Not defined for
32-bit builds.
V2 -> V3:
+ rebase to 23-mm1 atop RvR's split lru series
+ fix page flags macros for *PageMlocked() when not configured.
+ ensure lru_add_drain_all() runs on all cpus when NORECLAIM_MLOCK
configured. Was just for NUMA.
V1 -> V2:
+ moved this patch [and related patches] up to right after
ramdisk/ramfs and SHM_LOCKed patches.
+ add [back] missing put_page() in putback_lru_page().
This solved page leakage as seen by stats in previous
version.
+ fix up munlock_vma_page() to isolate page from lru
before calling try_to_unlock(). Think I detected a
race here.
+ use TestClearPageMlock() on old page in migrate.c's
migrate_page_copy() to clean up old page.
+ live dangerously: remove TestSetPageLocked() in
is_mlocked_vma()--should only be called on new pages in
the fault path--iff we chose to cull there [later patch].
+ Add PG_mlocked to free_pages_check() etc to detect mlock
state mismanagement.
NOTE: temporarily [???] commented out--tripping over it
under load. Why?
Rework of Nick Piggins's "mm: move mlocked pages off the LRU" patch
-- part 1 of 2.
include/linux/mm.h | 5
include/linux/page-flags.h | 11 +
include/linux/rmap.h | 14 +
mm/internal.h | 63 +++++++
mm/memory.c | 19 ++
mm/migrate.c | 2
mm/mlock.c | 383 ++++++++++++++++++++++++++++++++++++++++++---
mm/mmap.c | 2
mm/page_alloc.c | 9 -
mm/rmap.c | 255 +++++++++++++++++++++++++----
mm/swap.c | 2
mm/vmscan.c | 36 +++-
12 files changed, 732 insertions(+), 69 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/internal.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/internal.h 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/internal.h 2008-06-10 22:27:14.000000000 -0400
@@ -61,6 +61,10 @@ static inline unsigned long page_order(s
return page_private(page);
}
+extern int mlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end);
+extern void munlock_vma_pages_all(struct vm_area_struct *vma);
+
#ifdef CONFIG_UNEVICTABLE_LRU
/*
* unevictable_migrate_page() called only from migrate_page_copy() to
@@ -79,6 +83,65 @@ static inline void unevictable_migrate_p
}
#endif
+#ifdef CONFIG_UNEVICTABLE_LRU
+/*
+ * Called only in fault path via page_evictable() for a new page
+ * to determine if it's being mapped into a LOCKED vma.
+ * If so, mark page as mlocked.
+ */
+static inline int is_mlocked_vma(struct vm_area_struct *vma, struct page *page)
+{
+ VM_BUG_ON(PageLRU(page));
+
+ if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
+ return 0;
+
+ SetPageMlocked(page);
+ return 1;
+}
+
+/*
+ * must be called with vma's mmap_sem held for read, and page locked.
+ */
+extern void mlock_vma_page(struct page *page);
+
+/*
+ * Clear the page's PageMlocked(). This can be useful in a situation where
+ * we want to unconditionally remove a page from the pagecache -- e.g.,
+ * on truncation or freeing.
+ *
+ * It is legal to call this function for any page, mlocked or not.
+ * If called for a page that is still mapped by mlocked vmas, all we do
+ * is revert to lazy LRU behaviour -- semantics are not broken.
+ */
+extern void __clear_page_mlock(struct page *page);
+static inline void clear_page_mlock(struct page *page)
+{
+ if (unlikely(TestClearPageMlocked(page)))
+ __clear_page_mlock(page);
+}
+
+/*
+ * mlock_migrate_page - called only from migrate_page_copy() to
+ * migrate the Mlocked page flag
+ */
+static inline void mlock_migrate_page(struct page *newpage, struct page *page)
+{
+ if (TestClearPageMlocked(page))
+ SetPageMlocked(newpage);
+}
+
+
+#else /* CONFIG_UNEVICTABLE_LRU */
+static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
+{
+ return 0;
+}
+static inline void clear_page_mlock(struct page *page) { }
+static inline void mlock_vma_page(struct page *page) { }
+static inline void mlock_migrate_page(struct page *new, struct page *old) { }
+
+#endif /* CONFIG_UNEVICTABLE_LRU */
/*
* FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
Index: linux-2.6.26-rc5-mm2/mm/mlock.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mlock.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mlock.c 2008-06-10 22:28:01.000000000 -0400
@@ -8,10 +8,18 @@
#include <linux/capability.h>
#include <linux/mman.h>
#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pagemap.h>
#include <linux/mempolicy.h>
#include <linux/syscalls.h>
#include <linux/sched.h>
#include <linux/module.h>
+#include <linux/rmap.h>
+#include <linux/mmzone.h>
+#include <linux/hugetlb.h>
+
+#include "internal.h"
int can_do_mlock(void)
{
@@ -23,17 +31,350 @@ int can_do_mlock(void)
}
EXPORT_SYMBOL(can_do_mlock);
+#ifdef CONFIG_UNEVICTABLE_LRU
+/*
+ * Mlocked pages are marked with PageMlocked() flag for efficient testing
+ * in vmscan and, possibly, the fault path; and to support semi-accurate
+ * statistics.
+ *
+ * An mlocked page [PageMlocked(page)] is unevictable. As such, it will
+ * be placed on the LRU "unevictable" list, rather than the [in]active lists.
+ * The unevictable list is an LRU sibling list to the [in]active lists.
+ * PageUnevictable is set to indicate the unevictable state.
+ *
+ * When lazy mlocking via vmscan, it is important to ensure that the
+ * vma's VM_LOCKED status is not concurrently being modified, otherwise we
+ * may have mlocked a page that is being munlocked. So lazy mlock must take
+ * the mmap_sem for read, and verify that the vma really is locked
+ * (see mm/rmap.c).
+ */
+
+/*
+ * LRU accounting for clear_page_mlock()
+ */
+void __clear_page_mlock(struct page *page)
+{
+ VM_BUG_ON(!PageLocked(page)); /* for LRU isolate/putback */
+
+ if (!isolate_lru_page(page)) {
+ putback_lru_page(page);
+ } else {
+ /*
+ * Page not on the LRU yet. Flush all pagevecs and retry.
+ */
+ lru_add_drain_all();
+ if (!isolate_lru_page(page))
+ putback_lru_page(page);
+ }
+}
+
+/*
+ * Mark page as mlocked if not already.
+ * If page on LRU, isolate and putback to move to unevictable list.
+ */
+void mlock_vma_page(struct page *page)
+{
+ BUG_ON(!PageLocked(page));
+
+ if (!TestSetPageMlocked(page) && !isolate_lru_page(page))
+ putback_lru_page(page);
+}
+
+/*
+ * called from munlock()/munmap() path with page supposedly on the LRU.
+ *
+ * Note: unlike mlock_vma_page(), we can't just clear the PageMlocked
+ * [in try_to_munlock()] and then attempt to isolate the page. We must
+ * isolate the page to keep others from messing with its unevictable
+ * and mlocked state while trying to munlock. However, we pre-clear the
+ * mlocked state anyway as we might lose the isolation race and we might
+ * not get another chance to clear PageMlocked. If we successfully
+ * isolate the page and try_to_munlock() detects other VM_LOCKED vmas
+ * mapping the page, it will restore the PageMlocked state, unless the page
+ * is mapped in a non-linear vma. So, we go ahead and SetPageMlocked(),
+ * perhaps redundantly.
+ * If we lose the isolation race, and the page is mapped by other VM_LOCKED
+ * vmas, we'll detect this in vmscan--via try_to_munlock() or try_to_unmap()
+ * either of which will restore the PageMlocked state by calling
+ * mlock_vma_page() above, if it can grab the vma's mmap sem.
+ */
+static void munlock_vma_page(struct page *page)
+{
+ BUG_ON(!PageLocked(page));
+
+ if (TestClearPageMlocked(page) && !isolate_lru_page(page)) {
+ try_to_munlock(page);
+ putback_lru_page(page);
+ }
+}
+
+/*
+ * mlock a range of pages in the vma.
+ *
+ * This takes care of making the pages present too.
+ *
+ * vma->vm_mm->mmap_sem must be held for write.
+ */
+static int __mlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long addr = start;
+ struct page *pages[16]; /* 16 gives a reasonable batch */
+ int write = !!(vma->vm_flags & VM_WRITE);
+ int nr_pages = (end - start) / PAGE_SIZE;
+ int ret;
+
+ VM_BUG_ON(start & ~PAGE_MASK || end & ~PAGE_MASK);
+ VM_BUG_ON(start < vma->vm_start || end > vma->vm_end);
+ VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem));
+
+ lru_add_drain_all(); /* push cached pages to LRU */
+
+ while (nr_pages > 0) {
+ int i;
+
+ cond_resched();
+
+ /*
+ * get_user_pages makes pages present if we are
+ * setting mlock.
+ */
+ ret = get_user_pages(current, mm, addr,
+ min_t(int, nr_pages, ARRAY_SIZE(pages)),
+ write, 0, pages, NULL);
+ /*
+ * This can happen for, e.g., VM_NONLINEAR regions before
+ * a page has been allocated and mapped at a given offset,
+ * or for addresses that map beyond end of a file.
+ * We'll mlock the the pages if/when they get faulted in.
+ */
+ if (ret < 0)
+ break;
+ if (ret == 0) {
+ /*
+ * We know the vma is there, so the only time
+ * we cannot get a single page should be an
+ * error (ret < 0) case.
+ */
+ WARN_ON(1);
+ break;
+ }
+
+ lru_add_drain(); /* push cached pages to LRU */
+
+ for (i = 0; i < ret; i++) {
+ struct page *page = pages[i];
+
+ /*
+ * page might be truncated or migrated out from under
+ * us. Check after acquiring page lock.
+ */
+ lock_page(page);
+ if (page->mapping)
+ mlock_vma_page(page);
+ unlock_page(page);
+ put_page(page); /* ref from get_user_pages() */
+
+ /*
+ * here we assume that get_user_pages() has given us
+ * a list of virtually contiguous pages.
+ */
+ addr += PAGE_SIZE; /* for next get_user_pages() */
+ nr_pages--;
+ }
+ }
+
+ lru_add_drain_all(); /* to update stats */
+
+ return 0; /* count entire vma as locked_vm */
+}
+
+/*
+ * private structure for munlock page table walk
+ */
+struct munlock_page_walk {
+ struct vm_area_struct *vma;
+ pmd_t *pmd; /* for migration_entry_wait() */
+};
+
+/*
+ * munlock normal pages for present ptes
+ */
+static int __munlock_pte_handler(pte_t *ptep, unsigned long addr,
+ unsigned long end, void *private)
+{
+ struct munlock_page_walk *mpw = private;
+ swp_entry_t entry;
+ struct page *page;
+ pte_t pte;
+
+retry:
+ pte = *ptep;
+ /*
+ * If it's a swap pte, we might be racing with page migration.
+ */
+ if (unlikely(!pte_present(pte))) {
+ if (!is_swap_pte(pte))
+ goto out;
+ entry = pte_to_swp_entry(pte);
+ if (is_migration_entry(entry)) {
+ migration_entry_wait(mpw->vma->vm_mm, mpw->pmd, addr);
+ goto retry;
+ }
+ goto out;
+ }
+
+ page = vm_normal_page(mpw->vma, addr, pte);
+ if (!page)
+ goto out;
+
+ lock_page(page);
+ if (!page->mapping) {
+ unlock_page(page);
+ goto retry;
+ }
+ munlock_vma_page(page);
+ unlock_page(page);
+
+out:
+ return 0;
+}
+
+/*
+ * Save pmd for pte handler for waiting on migration entries
+ */
+static int __munlock_pmd_handler(pmd_t *pmd, unsigned long addr,
+ unsigned long end, void *private)
+{
+ struct munlock_page_walk *mpw = private;
+
+ mpw->pmd = pmd;
+ return 0;
+}
+
+static struct mm_walk munlock_page_walk = {
+ .pmd_entry = __munlock_pmd_handler,
+ .pte_entry = __munlock_pte_handler,
+};
+
+/*
+ * munlock a range of pages in the vma using standard page table walk.
+ *
+ * vma->vm_mm->mmap_sem must be held for write.
+ */
+static void __munlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct munlock_page_walk mpw;
+
+ VM_BUG_ON(start & ~PAGE_MASK || end & ~PAGE_MASK);
+ VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem));
+ VM_BUG_ON(start < vma->vm_start);
+ VM_BUG_ON(end > vma->vm_end);
+
+ lru_add_drain_all(); /* push cached pages to LRU */
+ mpw.vma = vma;
+ walk_page_range(mm, start, end, &munlock_page_walk, &mpw);
+ lru_add_drain_all(); /* to update stats */
+}
+
+#else /* CONFIG_UNEVICTABLE_LRU */
+
+/*
+ * Just make pages present if VM_LOCKED. No-op if unlocking.
+ */
+static int __mlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ if (vma->vm_flags & VM_LOCKED)
+ make_pages_present(start, end);
+ return 0;
+}
+
+/*
+ * munlock a range of pages in the vma -- no-op.
+ */
+static void __munlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+}
+#endif /* CONFIG_UNEVICTABLE_LRU */
+
+/*
+ * mlock all pages in this vma range. For mmap()/mremap()/...
+ */
+int mlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ int nr_pages = (end - start) / PAGE_SIZE;
+ BUG_ON(!(vma->vm_flags & VM_LOCKED));
+
+ /*
+ * filter unlockable vmas
+ */
+ if (vma->vm_flags & (VM_IO | VM_PFNMAP))
+ goto no_mlock;
+
+ if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) ||
+ is_vm_hugetlb_page(vma) ||
+ vma == get_gate_vma(current)))
+ return __mlock_vma_pages_range(vma, start, end);
+
+ /*
+ * User mapped kernel pages or huge pages:
+ * make these pages present to populate the ptes, but
+ * fall thru' to reset VM_LOCKED--no need to unlock, and
+ * return nr_pages so these don't get counted against task's
+ * locked limit. huge pages are already counted against
+ * locked vm limit.
+ */
+ make_pages_present(start, end);
+
+no_mlock:
+ vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */
+ return nr_pages; /* pages NOT mlocked */
+}
+
+
+/*
+ * munlock all pages in vma. For munmap() and exit().
+ */
+void munlock_vma_pages_all(struct vm_area_struct *vma)
+{
+ vma->vm_flags &= ~VM_LOCKED;
+ __munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
+}
+
+/*
+ * mlock_fixup - handle mlock[all]/munlock[all] requests.
+ *
+ * Filters out "special" vmas -- VM_LOCKED never gets set for these, and
+ * munlock is a no-op. However, for some special vmas, we go ahead and
+ * populate the ptes via make_pages_present().
+ *
+ * For vmas that pass the filters, merge/split as appropriate.
+ */
static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
unsigned long start, unsigned long end, unsigned int newflags)
{
- struct mm_struct * mm = vma->vm_mm;
+ struct mm_struct *mm = vma->vm_mm;
pgoff_t pgoff;
- int pages;
+ int nr_pages;
int ret = 0;
+ int lock = newflags & VM_LOCKED;
- if (newflags == vma->vm_flags) {
- *prev = vma;
- goto out;
+ if (newflags == vma->vm_flags ||
+ (vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ goto out; /* don't set VM_LOCKED, don't count */
+
+ if ((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) ||
+ is_vm_hugetlb_page(vma) ||
+ vma == get_gate_vma(current)) {
+ if (lock)
+ make_pages_present(start, end);
+ goto out; /* don't set VM_LOCKED, don't count */
}
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
@@ -44,8 +385,6 @@ static int mlock_fixup(struct vm_area_st
goto success;
}
- *prev = vma;
-
if (start != vma->vm_start) {
ret = split_vma(mm, vma, start, 1);
if (ret)
@@ -60,24 +399,31 @@ static int mlock_fixup(struct vm_area_st
success:
/*
+ * Keep track of amount of locked VM.
+ */
+ nr_pages = (end - start) >> PAGE_SHIFT;
+ if (!lock)
+ nr_pages = -nr_pages;
+ mm->locked_vm += nr_pages;
+
+ /*
* vm_flags is protected by the mmap_sem held in write mode.
* It's okay if try_to_unmap_one unmaps a page just after we
- * set VM_LOCKED, make_pages_present below will bring it back.
+ * set VM_LOCKED, __mlock_vma_pages_range will bring it back.
*/
vma->vm_flags = newflags;
- /*
- * Keep track of amount of locked VM.
- */
- pages = (end - start) >> PAGE_SHIFT;
- if (newflags & VM_LOCKED) {
- pages = -pages;
- if (!(newflags & VM_IO))
- ret = make_pages_present(start, end);
- }
+ if (lock) {
+ ret = __mlock_vma_pages_range(vma, start, end);
+ if (ret > 0) {
+ mm->locked_vm -= ret;
+ ret = 0;
+ }
+ } else
+ __munlock_vma_pages_range(vma, start, end);
- mm->locked_vm -= pages;
out:
+ *prev = vma;
if (ret == -ENOMEM)
ret = -EAGAIN;
return ret;
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 22:27:14.000000000 -0400
@@ -552,11 +552,8 @@ static unsigned long shrink_page_list(st
sc->nr_scanned++;
- if (unlikely(!page_evictable(page, NULL))) {
- if (putback_lru_page(page))
- unlock_page(page);
- continue;
- }
+ if (unlikely(!page_evictable(page, NULL)))
+ goto cull_mlocked;
if (!sc->may_swap && page_mapped(page))
goto keep_locked;
@@ -594,9 +591,19 @@ static unsigned long shrink_page_list(st
* Anonymous process memory has backing store?
* Try to allocate it some swap space here.
*/
- if (PageAnon(page) && !PageSwapCache(page))
+ if (PageAnon(page) && !PageSwapCache(page)) {
+ switch (try_to_munlock(page)) {
+ case SWAP_FAIL: /* shouldn't happen */
+ case SWAP_AGAIN:
+ goto keep_locked;
+ case SWAP_MLOCK:
+ goto cull_mlocked;
+ case SWAP_SUCCESS:
+ ; /* fall thru'; add to swap cache */
+ }
if (!add_to_swap(page, GFP_ATOMIC))
goto activate_locked;
+ }
#endif /* CONFIG_SWAP */
mapping = page_mapping(page);
@@ -611,6 +618,8 @@ static unsigned long shrink_page_list(st
goto activate_locked;
case SWAP_AGAIN:
goto keep_locked;
+ case SWAP_MLOCK:
+ goto cull_mlocked;
case SWAP_SUCCESS:
; /* try to free the page below */
}
@@ -685,6 +694,11 @@ free_it:
__pagevec_release_nonlru(&freed_pvec);
continue;
+cull_mlocked:
+ if (putback_lru_page(page))
+ unlock_page(page);
+ continue;
+
activate_locked:
/* Not a candidate for swapping, so reclaim swap space. */
if (PageSwapCache(page) && vm_swap_full())
@@ -696,7 +710,7 @@ keep_locked:
unlock_page(page);
keep:
list_add(&page->lru, &ret_pages);
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
}
list_splice(&ret_pages, page_list);
if (pagevec_count(&freed_pvec))
@@ -2317,12 +2331,13 @@ int zone_reclaim(struct zone *zone, gfp_
* @vma: the VMA in which the page is or will be mapped, may be NULL
*
* Test whether page is evictable--i.e., should be placed on active/inactive
- * lists vs unevictable list.
+ * lists vs unevictable list. The vma argument is !NULL when called from the
+ * fault path to determine how to instantate a new page.
*
* Reasons page might not be evictable:
* (1) page's mapping marked unevictable
+ * (2) page is part of an mlocked VMA
*
- * TODO - later patches
*/
int page_evictable(struct page *page, struct vm_area_struct *vma)
{
@@ -2332,7 +2347,8 @@ int page_evictable(struct page *page, st
if (mapping_unevictable(page_mapping(page)))
return 0;
- /* TODO: test page [!]evictable conditions */
+ if (PageMlocked(page) || (vma && is_mlocked_vma(vma, page)))
+ return 0;
return 1;
}
Index: linux-2.6.26-rc5-mm2/include/linux/page-flags.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/page-flags.h 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/page-flags.h 2008-06-10 22:20:57.000000000 -0400
@@ -96,6 +96,7 @@ enum pageflags {
PG_swapbacked, /* Page is backed by RAM/swap */
#ifdef CONFIG_UNEVICTABLE_LRU
PG_unevictable, /* Page is "unevictable" */
+ PG_mlocked, /* Page is vma mlocked */
#endif
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PG_uncached, /* Page has been mapped as uncached */
@@ -232,7 +233,17 @@ PAGEFLAG_FALSE(SwapCache)
#ifdef CONFIG_UNEVICTABLE_LRU
PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
TESTCLEARFLAG(Unevictable, unevictable)
+
+#define MLOCK_PAGES 1
+PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
+ TESTSCFLAG(Mlocked, mlocked)
+
#else
+
+#define MLOCK_PAGES 0
+PAGEFLAG_FALSE(Mlocked)
+ SETPAGEFLAG_NOOP(Mlocked) TESTCLEARFLAG_FALSE(Mlocked)
+
PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable)
SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable)
__CLEARPAGEFLAG_NOOP(Unevictable)
Index: linux-2.6.26-rc5-mm2/include/linux/rmap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/rmap.h 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/rmap.h 2008-06-10 22:27:14.000000000 -0400
@@ -109,6 +109,19 @@ unsigned long page_address_in_vma(struct
*/
int page_mkclean(struct page *);
+#ifdef CONFIG_UNEVICTABLE_LRU
+/*
+ * called in munlock()/munmap() path to check for other vmas holding
+ * the page mlocked.
+ */
+int try_to_munlock(struct page *);
+#else
+static inline int try_to_munlock(struct page *page)
+{
+ return 0; /* a.k.a. SWAP_SUCCESS */
+}
+#endif
+
#else /* !CONFIG_MMU */
#define anon_vma_init() do {} while (0)
@@ -132,5 +145,6 @@ static inline int page_mkclean(struct pa
#define SWAP_SUCCESS 0
#define SWAP_AGAIN 1
#define SWAP_FAIL 2
+#define SWAP_MLOCK 3
#endif /* _LINUX_RMAP_H */
Index: linux-2.6.26-rc5-mm2/mm/rmap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/rmap.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/rmap.c 2008-06-10 22:27:14.000000000 -0400
@@ -52,6 +52,8 @@
#include <asm/tlbflush.h>
+#include "internal.h"
+
struct kmem_cache *anon_vma_cachep;
/* This must be called under the mmap_sem. */
@@ -263,6 +265,32 @@ pte_t *page_check_address(struct page *p
return NULL;
}
+/**
+ * page_mapped_in_vma - check whether a page is really mapped in a VMA
+ * @page: the page to test
+ * @vma: the VMA to test
+ *
+ * Returns 1 if the page is mapped into the page tables of the VMA, 0
+ * if the page is not mapped into the page tables of this VMA. Only
+ * valid for normal file or anonymous VMAs.
+ */
+static int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
+{
+ unsigned long address;
+ pte_t *pte;
+ spinlock_t *ptl;
+
+ address = vma_address(page, vma);
+ if (address == -EFAULT) /* out of vma range */
+ return 0;
+ pte = page_check_address(page, vma->vm_mm, address, &ptl);
+ if (!pte) /* the page is not in this mm */
+ return 0;
+ pte_unmap_unlock(pte, ptl);
+
+ return 1;
+}
+
/*
* Subfunctions of page_referenced: page_referenced_one called
* repeatedly from either page_referenced_anon or page_referenced_file.
@@ -284,10 +312,17 @@ static int page_referenced_one(struct pa
if (!pte)
goto out;
+ /*
+ * Don't want to elevate referenced for mlocked page that gets this far,
+ * in order that it progresses to try_to_unmap and is moved to the
+ * unevictable list.
+ */
if (vma->vm_flags & VM_LOCKED) {
- referenced++;
*mapcount = 1; /* break early from loop */
- } else if (ptep_clear_flush_young(vma, address, pte))
+ goto out_unmap;
+ }
+
+ if (ptep_clear_flush_young(vma, address, pte))
referenced++;
/* Pretend the page is referenced if the task has the
@@ -296,6 +331,7 @@ static int page_referenced_one(struct pa
rwsem_is_locked(&mm->mmap_sem))
referenced++;
+out_unmap:
(*mapcount)--;
pte_unmap_unlock(pte, ptl);
out:
@@ -385,11 +421,6 @@ static int page_referenced_file(struct p
*/
if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont))
continue;
- if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE))
- == (VM_LOCKED|VM_MAYSHARE)) {
- referenced++;
- break;
- }
referenced += page_referenced_one(page, vma, &mapcount);
if (!mapcount)
break;
@@ -704,10 +735,15 @@ static int try_to_unmap_one(struct page
* If it's recently referenced (perhaps page_referenced
* skipped over this mm) then we should reactivate it.
*/
- if (!migration && ((vma->vm_flags & VM_LOCKED) ||
- (ptep_clear_flush_young(vma, address, pte)))) {
- ret = SWAP_FAIL;
- goto out_unmap;
+ if (!migration) {
+ if (vma->vm_flags & VM_LOCKED) {
+ ret = SWAP_MLOCK;
+ goto out_unmap;
+ }
+ if (ptep_clear_flush_young(vma, address, pte)) {
+ ret = SWAP_FAIL;
+ goto out_unmap;
+ }
}
/* Nuke the page table entry. */
@@ -789,12 +825,17 @@ out:
* For very sparsely populated VMAs this is a little inefficient - chances are
* there there won't be many ptes located within the scan cluster. In this case
* maybe we could scan further - to the end of the pte page, perhaps.
+ *
+ * Mlocked pages: check VM_LOCKED under mmap_sem held for read, if we can
+ * acquire it without blocking. If vma locked, mlock the pages in the cluster,
+ * rather than unmapping them. If we encounter the "check_page" that vmscan is
+ * trying to unmap, return SWAP_MLOCK, else default SWAP_AGAIN.
*/
#define CLUSTER_SIZE min(32*PAGE_SIZE, PMD_SIZE)
#define CLUSTER_MASK (~(CLUSTER_SIZE - 1))
-static void try_to_unmap_cluster(unsigned long cursor,
- unsigned int *mapcount, struct vm_area_struct *vma)
+static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
+ struct vm_area_struct *vma, struct page *check_page)
{
struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
@@ -806,6 +847,8 @@ static void try_to_unmap_cluster(unsigne
struct page *page;
unsigned long address;
unsigned long end;
+ int ret = SWAP_AGAIN;
+ int locked_vma = 0;
address = (vma->vm_start + cursor) & CLUSTER_MASK;
end = address + CLUSTER_SIZE;
@@ -816,15 +859,26 @@ static void try_to_unmap_cluster(unsigne
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
- return;
+ return ret;
pud = pud_offset(pgd, address);
if (!pud_present(*pud))
- return;
+ return ret;
pmd = pmd_offset(pud, address);
if (!pmd_present(*pmd))
- return;
+ return ret;
+
+ /*
+ * MLOCK_PAGES => feature is configured.
+ * if we can acquire the mmap_sem for read, and vma is VM_LOCKED,
+ * keep the sem while scanning the cluster for mlocking pages.
+ */
+ if (MLOCK_PAGES && down_read_trylock(&vma->vm_mm->mmap_sem)) {
+ locked_vma = (vma->vm_flags & VM_LOCKED);
+ if (!locked_vma)
+ up_read(&vma->vm_mm->mmap_sem); /* don't need it */
+ }
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
@@ -837,6 +891,13 @@ static void try_to_unmap_cluster(unsigne
page = vm_normal_page(vma, address, *pte);
BUG_ON(!page || PageAnon(page));
+ if (locked_vma) {
+ mlock_vma_page(page); /* no-op if already mlocked */
+ if (page == check_page)
+ ret = SWAP_MLOCK;
+ continue; /* don't unmap */
+ }
+
if (ptep_clear_flush_young(vma, address, pte))
continue;
@@ -858,39 +919,104 @@ static void try_to_unmap_cluster(unsigne
(*mapcount)--;
}
pte_unmap_unlock(pte - 1, ptl);
+ if (locked_vma)
+ up_read(&vma->vm_mm->mmap_sem);
+ return ret;
}
-static int try_to_unmap_anon(struct page *page, int migration)
+/*
+ * common handling for pages mapped in VM_LOCKED vmas
+ */
+static int try_to_mlock_page(struct page *page, struct vm_area_struct *vma)
+{
+ int mlocked = 0;
+
+ if (down_read_trylock(&vma->vm_mm->mmap_sem)) {
+ if (vma->vm_flags & VM_LOCKED) {
+ mlock_vma_page(page);
+ mlocked++; /* really mlocked the page */
+ }
+ up_read(&vma->vm_mm->mmap_sem);
+ }
+ return mlocked;
+}
+
+/**
+ * try_to_unmap_anon - unmap or unlock anonymous page using the object-based
+ * rmap method
+ * @page: the page to unmap/unlock
+ * @unlock: request for unlock rather than unmap [unlikely]
+ * @migration: unmapping for migration - ignored if @unlock
+ *
+ * Find all the mappings of a page using the mapping pointer and the vma chains
+ * contained in the anon_vma struct it points to.
+ *
+ * This function is only called from try_to_unmap/try_to_munlock for
+ * anonymous pages.
+ * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
+ * where the page was found will be held for write. So, we won't recheck
+ * vm_flags for that VMA. That should be OK, because that vma shouldn't be
+ * 'LOCKED.
+ */
+static int try_to_unmap_anon(struct page *page, int unlock, int migration)
{
struct anon_vma *anon_vma;
struct vm_area_struct *vma;
+ unsigned int mlocked = 0;
int ret = SWAP_AGAIN;
+ if (MLOCK_PAGES && unlikely(unlock))
+ ret = SWAP_SUCCESS; /* default for try_to_munlock() */
+
anon_vma = page_lock_anon_vma(page);
if (!anon_vma)
return ret;
list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
- ret = try_to_unmap_one(page, vma, migration);
- if (ret == SWAP_FAIL || !page_mapped(page))
- break;
+ if (MLOCK_PAGES && unlikely(unlock)) {
+ if (!((vma->vm_flags & VM_LOCKED) &&
+ page_mapped_in_vma(page, vma)))
+ continue; /* must visit all unlocked vmas */
+ ret = SWAP_MLOCK; /* saw at least one mlocked vma */
+ } else {
+ ret = try_to_unmap_one(page, vma, migration);
+ if (ret == SWAP_FAIL || !page_mapped(page))
+ break;
+ }
+ if (ret == SWAP_MLOCK) {
+ mlocked = try_to_mlock_page(page, vma);
+ if (mlocked)
+ break; /* stop if actually mlocked page */
+ }
}
page_unlock_anon_vma(anon_vma);
+
+ if (mlocked)
+ ret = SWAP_MLOCK; /* actually mlocked the page */
+ else if (ret == SWAP_MLOCK)
+ ret = SWAP_AGAIN; /* saw VM_LOCKED vma */
+
return ret;
}
/**
- * try_to_unmap_file - unmap file page using the object-based rmap method
- * @page: the page to unmap
- * @migration: migration flag
+ * try_to_unmap_file - unmap/unlock file page using the object-based rmap method
+ * @page: the page to unmap/unlock
+ * @unlock: request for unlock rather than unmap [unlikely]
+ * @migration: unmapping for migration - ignored if @unlock
*
* Find all the mappings of a page using the mapping pointer and the vma chains
* contained in the address_space struct it points to.
*
- * This function is only called from try_to_unmap for object-based pages.
+ * This function is only called from try_to_unmap/try_to_munlock for
+ * object-based pages.
+ * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
+ * where the page was found will be held for write. So, we won't recheck
+ * vm_flags for that VMA. That should be OK, because that vma shouldn't be
+ * 'LOCKED.
*/
-static int try_to_unmap_file(struct page *page, int migration)
+static int try_to_unmap_file(struct page *page, int unlock, int migration)
{
struct address_space *mapping = page->mapping;
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -901,20 +1027,44 @@ static int try_to_unmap_file(struct page
unsigned long max_nl_cursor = 0;
unsigned long max_nl_size = 0;
unsigned int mapcount;
+ unsigned int mlocked = 0;
+
+ if (MLOCK_PAGES && unlikely(unlock))
+ ret = SWAP_SUCCESS; /* default for try_to_munlock() */
spin_lock(&mapping->i_mmap_lock);
vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
- ret = try_to_unmap_one(page, vma, migration);
- if (ret == SWAP_FAIL || !page_mapped(page))
- goto out;
+ if (MLOCK_PAGES && unlikely(unlock)) {
+ if (!(vma->vm_flags & VM_LOCKED))
+ continue; /* must visit all vmas */
+ ret = SWAP_MLOCK;
+ } else {
+ ret = try_to_unmap_one(page, vma, migration);
+ if (ret == SWAP_FAIL || !page_mapped(page))
+ goto out;
+ }
+ if (ret == SWAP_MLOCK) {
+ mlocked = try_to_mlock_page(page, vma);
+ if (mlocked)
+ break; /* stop if actually mlocked page */
+ }
}
+ if (mlocked)
+ goto out;
+
if (list_empty(&mapping->i_mmap_nonlinear))
goto out;
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if ((vma->vm_flags & VM_LOCKED) && !migration)
+ if (MLOCK_PAGES && unlikely(unlock)) {
+ if (!(vma->vm_flags & VM_LOCKED))
+ continue; /* must visit all vmas */
+ ret = SWAP_MLOCK; /* leave mlocked == 0 */
+ goto out; /* no need to look further */
+ }
+ if (!MLOCK_PAGES && !migration && (vma->vm_flags & VM_LOCKED))
continue;
cursor = (unsigned long) vma->vm_private_data;
if (cursor > max_nl_cursor)
@@ -924,7 +1074,7 @@ static int try_to_unmap_file(struct page
max_nl_size = cursor;
}
- if (max_nl_size == 0) { /* any nonlinears locked or reserved */
+ if (max_nl_size == 0) { /* all nonlinears locked or reserved ? */
ret = SWAP_FAIL;
goto out;
}
@@ -948,12 +1098,16 @@ static int try_to_unmap_file(struct page
do {
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if ((vma->vm_flags & VM_LOCKED) && !migration)
+ if (!MLOCK_PAGES && !migration &&
+ (vma->vm_flags & VM_LOCKED))
continue;
cursor = (unsigned long) vma->vm_private_data;
while ( cursor < max_nl_cursor &&
cursor < vma->vm_end - vma->vm_start) {
- try_to_unmap_cluster(cursor, &mapcount, vma);
+ ret = try_to_unmap_cluster(cursor, &mapcount,
+ vma, page);
+ if (ret == SWAP_MLOCK)
+ mlocked = 2; /* to return below */
cursor += CLUSTER_SIZE;
vma->vm_private_data = (void *) cursor;
if ((int)mapcount <= 0)
@@ -974,6 +1128,10 @@ static int try_to_unmap_file(struct page
vma->vm_private_data = NULL;
out:
spin_unlock(&mapping->i_mmap_lock);
+ if (mlocked)
+ ret = SWAP_MLOCK; /* actually mlocked the page */
+ else if (ret == SWAP_MLOCK)
+ ret = SWAP_AGAIN; /* saw VM_LOCKED vma */
return ret;
}
@@ -989,6 +1147,7 @@ out:
* SWAP_SUCCESS - we succeeded in removing all mappings
* SWAP_AGAIN - we missed a mapping, try again later
* SWAP_FAIL - the page is unswappable
+ * SWAP_MLOCK - page is mlocked.
*/
int try_to_unmap(struct page *page, int migration)
{
@@ -997,12 +1156,36 @@ int try_to_unmap(struct page *page, int
BUG_ON(!PageLocked(page));
if (PageAnon(page))
- ret = try_to_unmap_anon(page, migration);
+ ret = try_to_unmap_anon(page, 0, migration);
else
- ret = try_to_unmap_file(page, migration);
-
- if (!page_mapped(page))
+ ret = try_to_unmap_file(page, 0, migration);
+ if (ret != SWAP_MLOCK && !page_mapped(page))
ret = SWAP_SUCCESS;
return ret;
}
+#ifdef CONFIG_UNEVICTABLE_LRU
+/**
+ * try_to_munlock - try to munlock a page
+ * @page: the page to be munlocked
+ *
+ * Called from munlock code. Checks all of the VMAs mapping the page
+ * to make sure nobody else has this page mlocked. The page will be
+ * returned with PG_mlocked cleared if no other vmas have it mlocked.
+ *
+ * Return values are:
+ *
+ * SWAP_SUCCESS - no vma's holding page mlocked.
+ * SWAP_AGAIN - page mapped in mlocked vma -- couldn't acquire mmap sem
+ * SWAP_MLOCK - page is now mlocked.
+ */
+int try_to_munlock(struct page *page)
+{
+ VM_BUG_ON(!PageLocked(page) || PageLRU(page));
+
+ if (PageAnon(page))
+ return try_to_unmap_anon(page, 1, 0);
+ else
+ return try_to_unmap_file(page, 1, 0);
+}
+#endif
Index: linux-2.6.26-rc5-mm2/mm/migrate.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/migrate.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/migrate.c 2008-06-10 22:20:57.000000000 -0400
@@ -357,6 +357,8 @@ static void migrate_page_copy(struct pag
__set_page_dirty_nobuffers(newpage);
}
+ mlock_migrate_page(newpage, page);
+
#ifdef CONFIG_SWAP
if (PageSwapCache(page)) {
ClearPageSwapCache(page);
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 22:27:14.000000000 -0400
@@ -243,6 +243,7 @@ static void bad_page(struct page *page)
1 << PG_active |
#ifdef CONFIG_UNEVICTABLE_LRU
1 << PG_unevictable |
+ 1 << PG_mlocked |
#endif
1 << PG_dirty |
1 << PG_reclaim |
@@ -480,6 +481,7 @@ static inline int free_pages_check(struc
#ifdef CONFIG_UNEVICTABLE_LRU
1 << PG_unevictable |
#endif
+ 1 << PG_mlocked |
1 << PG_buddy ))))
bad_page(page);
if (PageDirty(page))
@@ -633,6 +635,7 @@ static int prep_new_page(struct page *pa
1 << PG_active |
#ifdef CONFIG_UNEVICTABLE_LRU
1 << PG_unevictable |
+ 1 << PG_mlocked |
#endif
1 << PG_dirty |
1 << PG_slab |
@@ -652,7 +655,11 @@ static int prep_new_page(struct page *pa
page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_reclaim |
1 << PG_referenced | 1 << PG_arch_1 |
- 1 << PG_owner_priv_1 | 1 << PG_mappedtodisk);
+ 1 << PG_owner_priv_1 | 1 << PG_mappedtodisk
+#ifdef CONFIG_UNEVICTABLE_LRU
+ | 1 << PG_mlocked
+#endif
+ );
set_page_private(page, 0);
set_page_refcounted(page);
Index: linux-2.6.26-rc5-mm2/mm/swap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap.c 2008-06-10 22:27:14.000000000 -0400
@@ -278,7 +278,7 @@ void lru_add_drain(void)
put_cpu();
}
-#ifdef CONFIG_NUMA
+#if defined(CONFIG_NUMA) || defined(CONFIG_UNEVICTABLE_LRU)
static void lru_add_drain_per_cpu(struct work_struct *dummy)
{
lru_add_drain();
Index: linux-2.6.26-rc5-mm2/mm/memory.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memory.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memory.c 2008-06-10 22:27:14.000000000 -0400
@@ -63,6 +63,8 @@
#include "internal.h"
+#include "internal.h"
+
#ifndef CONFIG_NEED_MULTIPLE_NODES
/* use the per-pgdat data instead for discontigmem - mbligh */
unsigned long max_mapnr;
@@ -1773,6 +1775,15 @@ gotten:
new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
if (!new_page)
goto oom;
+ /*
+ * Don't let another task, with possibly unlocked vma,
+ * keep the mlocked page.
+ */
+ if (vma->vm_flags & VM_LOCKED) {
+ lock_page(old_page); /* for LRU manipulation */
+ clear_page_mlock(old_page);
+ unlock_page(old_page);
+ }
cow_user_page(new_page, old_page, address, vma);
__SetPageUptodate(new_page);
@@ -2215,7 +2226,7 @@ static int do_swap_page(struct mm_struct
page_add_anon_rmap(page, vma, address);
swap_free(entry);
- if (vm_swap_full())
+ if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
remove_exclusive_swap_page(page);
unlock_page(page);
@@ -2355,6 +2366,12 @@ static int __do_fault(struct mm_struct *
ret = VM_FAULT_OOM;
goto out;
}
+ /*
+ * Don't let another task, with possibly unlocked vma,
+ * keep the mlocked page.
+ */
+ if (vma->vm_flags & VM_LOCKED)
+ clear_page_mlock(vmf.page);
copy_user_highpage(page, vmf.page, address, vma);
__SetPageUptodate(page);
} else {
Index: linux-2.6.26-rc5-mm2/mm/mmap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mmap.c 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mmap.c 2008-06-10 22:27:14.000000000 -0400
@@ -661,8 +661,6 @@ again: remove_next = 1 + (end > next->
* If the vma has a ->close operation then the driver probably needs to release
* per-vma resources, so we don't attempt to merge those.
*/
-#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
-
static inline int is_mergeable_vma(struct vm_area_struct *vma,
struct file *file, unsigned long vm_flags)
{
Index: linux-2.6.26-rc5-mm2/include/linux/mm.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mm.h 2008-06-10 22:20:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mm.h 2008-06-10 22:20:57.000000000 -0400
@@ -127,6 +127,11 @@ extern unsigned int kobjsize(const void
#define VM_RandomReadHint(v) ((v)->vm_flags & VM_RAND_READ)
/*
+ * special vmas that are non-mergable, non-mlock()able
+ */
+#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
+
+/*
* mapping from the currently active vm_flags protection bits (the
* low four bits) to a page protection mask..
*/
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 17/24] mlock: downgrade mmap sem while populating mlocked regions
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (15 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 16/24] mlock: mlocked " Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 18/24] mmap: handle mlocked pages during map, remap, unmap Rik van Riel
` (7 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-downgrade-mmap-sem-while-populating-mlocked-regions.patch --]
[-- Type: text/plain, Size: 4836 bytes --]
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
We need to hold the mmap_sem for write to initiatate mlock()/munlock()
because we may need to merge/split vmas. However, this can lead to
very long lock hold times attempting to fault in a large memory region
to mlock it into memory. This can hold off other faults against the
mm [multithreaded tasks] and other scans of the mm, such as via /proc.
To alleviate this, downgrade the mmap_sem to read mode during the
population of the region for locking. This is especially the case
if we need to reclaim memory to lock down the region. We [probably?]
don't need to do this for unlocking as all of the pages should be
resident--they're already mlocked.
Now, the caller's of the mlock functions [mlock_fixup() and
mlock_vma_pages_range()] expect the mmap_sem to be returned in write
mode. Changing all callers appears to be way too much effort at this
point. So, restore write mode before returning. Note that this opens
a window where the mmap list could change in a multithreaded process.
So, at least for mlock_fixup(), where we could be called in a loop over
multiple vmas, we check that a vma still exists at the start address
and that vma still covers the page range [start,end). If not, we return
an error, -EAGAIN, and let the caller deal with it.
Return -EAGAIN from mlock_vma_pages_range() function and mlock_fixup()
if the vma at 'start' disappears or changes so that the page range
[start,end) is no longer contained in the vma. Again, let the caller
deal with it. Looks like only sys_remap_file_pages() [via mmap_region()]
should actually care.
With this patch, I no longer see processes like ps(1) blocked for seconds
or minutes at a time waiting for a large [multiple gigabyte] region to be
locked down. However, I occassionally see delays while unlocking or
unmapping a large mlocked region. Should we also downgrade the mmap_sem
for the unlock path?
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
V2 -> V3:
+ rebase to 23-mm1 atop RvR's split lru series [no change]
+ fix function return types [void -> int] to fix build when
not configured.
New in V2.
mm/mlock.c | 46 +++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 43 insertions(+), 3 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/mlock.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mlock.c 2008-06-10 22:28:01.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mlock.c 2008-06-10 22:28:05.000000000 -0400
@@ -308,6 +308,7 @@ static void __munlock_vma_pages_range(st
int mlock_vma_pages_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
+ struct mm_struct *mm = vma->vm_mm;
int nr_pages = (end - start) / PAGE_SIZE;
BUG_ON(!(vma->vm_flags & VM_LOCKED));
@@ -319,8 +320,19 @@ int mlock_vma_pages_range(struct vm_area
if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) ||
is_vm_hugetlb_page(vma) ||
- vma == get_gate_vma(current)))
- return __mlock_vma_pages_range(vma, start, end);
+ vma == get_gate_vma(current))) {
+ downgrade_write(&mm->mmap_sem);
+ nr_pages = __mlock_vma_pages_range(vma, start, end);
+
+ up_read(&mm->mmap_sem);
+ /* vma can change or disappear */
+ down_write(&mm->mmap_sem);
+ vma = find_vma(mm, start);
+ /* non-NULL vma must contain @start, but need to check @end */
+ if (!vma || end > vma->vm_end)
+ return -EAGAIN;
+ return nr_pages;
+ }
/*
* User mapped kernel pages or huge pages:
@@ -414,13 +426,41 @@ success:
vma->vm_flags = newflags;
if (lock) {
+ /*
+ * mmap_sem is currently held for write. Downgrade the write
+ * lock to a read lock so that other faults, mmap scans, ...
+ * while we fault in all pages.
+ */
+ downgrade_write(&mm->mmap_sem);
+
ret = __mlock_vma_pages_range(vma, start, end);
if (ret > 0) {
mm->locked_vm -= ret;
ret = 0;
}
- } else
+ /*
+ * Need to reacquire mmap sem in write mode, as our callers
+ * expect this. We have no support for atomically upgrading
+ * a sem to write, so we need to check for ranges while sem
+ * is unlocked.
+ */
+ up_read(&mm->mmap_sem);
+ /* vma can change or disappear */
+ down_write(&mm->mmap_sem);
+ *prev = find_vma(mm, start);
+ /* non-NULL *prev must contain @start, but need to check @end */
+ if (!(*prev) || end > (*prev)->vm_end)
+ ret = -EAGAIN;
+ } else {
+ /*
+ * TODO: for unlocking, pages will already be resident, so
+ * we don't need to wait for allocations/reclaim/pagein, ...
+ * However, unlocking a very large region can still take a
+ * while. Should we downgrade the semaphore for both lock
+ * AND unlock ?
+ */
__munlock_vma_pages_range(vma, start, end);
+ }
out:
*prev = vma;
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 18/24] mmap: handle mlocked pages during map, remap, unmap
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (16 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 17/24] mlock: downgrade mmap sem while populating mlocked regions Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 19/24] vmstat: mlocked pages statistics Rik van Riel
` (6 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, linux-mm,
Eric Whitney, Nick Piggin
[-- Attachment #1: vmscan-handle-mlocked-pages-during-map-remap-unmap.patch --]
[-- Type: text/plain, Size: 11297 bytes --]
Originally
From: Nick Piggin <npiggin@suse.de>
Remove mlocked pages from the LRU using "unevictable infrastructure"
during mmap(), munmap(), mremap() and truncate(). Try to move back
to normal LRU lists on munmap() when last mlocked mapping removed.
Remove PageMlocked() status when page truncated from file.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
V6:
+ munlock page in range of VM_LOCKED vma being covered by
remap_file_pages(), as this is an implied unmap of the
range.
+ in support of special vma filtering, don't account for
non-mlockable vmas as locked_vm.
V2 -> V3:
+ rebase to 23-mm1 atop RvR's split lru series [no changes]
V1 -> V2:
+ modified mmap.c:mmap_region() to return error if mlock_vma_pages_range()
does. This can only occur if the vma gets removed/changed while
we're switching mmap_sem lock modes. Most callers don't care, but
sys_remap_file_pages() appears to.
Rework of Nick Piggins's "mm: move mlocked pages off the LRU" patch
-- part 2 0f 2.
mm/fremap.c | 26 +++++++++++++++++---
mm/internal.h | 7 ++++-
mm/mlock.c | 10 ++++---
mm/mmap.c | 73 ++++++++++++++++++++++++++++++++++++++++++++--------------
mm/mremap.c | 8 +++---
mm/truncate.c | 4 +++
6 files changed, 99 insertions(+), 29 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/mmap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mmap.c 2008-06-10 22:27:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mmap.c 2008-06-10 22:28:19.000000000 -0400
@@ -969,6 +969,7 @@ unsigned long do_mmap_pgoff(struct file
return -EPERM;
vm_flags |= VM_LOCKED;
}
+
/* mlock MCL_FUTURE? */
if (vm_flags & VM_LOCKED) {
unsigned long locked, lock_limit;
@@ -1132,10 +1133,12 @@ munmap_back:
* The VM_SHARED test is necessary because shmem_zero_setup
* will create the file object for a shared anonymous map below.
*/
- if (!file && !(vm_flags & VM_SHARED) &&
- vma_merge(mm, prev, addr, addr + len, vm_flags,
- NULL, NULL, pgoff, NULL))
- goto out;
+ if (!file && !(vm_flags & VM_SHARED)) {
+ vma = vma_merge(mm, prev, addr, addr + len, vm_flags,
+ NULL, NULL, pgoff, NULL);
+ if (vma)
+ goto out;
+ }
/*
* Determine the object being mapped and call the appropriate
@@ -1217,10 +1220,14 @@ out:
mm->total_vm += len >> PAGE_SHIFT;
vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
if (vm_flags & VM_LOCKED) {
- mm->locked_vm += len >> PAGE_SHIFT;
- make_pages_present(addr, addr + len);
- }
- if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
+ /*
+ * makes pages present; downgrades, drops, reacquires mmap_sem
+ */
+ int nr_pages = mlock_vma_pages_range(vma, addr, addr + len);
+ if (nr_pages < 0)
+ return nr_pages; /* vma gone! */
+ mm->locked_vm += (len >> PAGE_SHIFT) - nr_pages;
+ } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
make_pages_present(addr, addr + len);
return addr;
@@ -1693,8 +1700,11 @@ find_extend_vma(struct mm_struct *mm, un
return vma;
if (!prev || expand_stack(prev, addr))
return NULL;
- if (prev->vm_flags & VM_LOCKED)
- make_pages_present(addr, prev->vm_end);
+ if (prev->vm_flags & VM_LOCKED) {
+ int nr_pages = mlock_vma_pages_range(prev, addr, prev->vm_end);
+ if (nr_pages < 0)
+ return NULL; /* vma gone! */
+ }
return prev;
}
#else
@@ -1720,8 +1730,11 @@ find_extend_vma(struct mm_struct * mm, u
start = vma->vm_start;
if (expand_stack(vma, addr))
return NULL;
- if (vma->vm_flags & VM_LOCKED)
- make_pages_present(addr, start);
+ if (vma->vm_flags & VM_LOCKED) {
+ int nr_pages = mlock_vma_pages_range(vma, addr, start);
+ if (nr_pages < 0)
+ return NULL; /* vma gone! */
+ }
return vma;
}
#endif
@@ -1908,6 +1921,18 @@ int do_munmap(struct mm_struct *mm, unsi
vma = prev? prev->vm_next: mm->mmap;
/*
+ * unlock any mlock()ed ranges before detaching vmas
+ */
+ if (mm->locked_vm) {
+ struct vm_area_struct *tmp = vma;
+ while (tmp && tmp->vm_start < end) {
+ if (tmp->vm_flags & VM_LOCKED)
+ munlock_vma_pages_all(tmp);
+ tmp = tmp->vm_next;
+ }
+ }
+
+ /*
* Remove the vma's, and unmap the actual pages
*/
detach_vmas_to_be_unmapped(mm, vma, prev, end);
@@ -2019,8 +2044,9 @@ unsigned long do_brk(unsigned long addr,
return -ENOMEM;
/* Can we just expand an old private anonymous mapping? */
- if (vma_merge(mm, prev, addr, addr + len, flags,
- NULL, NULL, pgoff, NULL))
+ vma = vma_merge(mm, prev, addr, addr + len, flags,
+ NULL, NULL, pgoff, NULL);
+ if (vma)
goto out;
/*
@@ -2042,8 +2068,9 @@ unsigned long do_brk(unsigned long addr,
out:
mm->total_vm += len >> PAGE_SHIFT;
if (flags & VM_LOCKED) {
- mm->locked_vm += len >> PAGE_SHIFT;
- make_pages_present(addr, addr + len);
+ int nr_pages = mlock_vma_pages_range(vma, addr, addr + len);
+ if (nr_pages >= 0)
+ mm->locked_vm += (len >> PAGE_SHIFT) - nr_pages;
}
return addr;
}
@@ -2054,13 +2081,25 @@ EXPORT_SYMBOL(do_brk);
void exit_mmap(struct mm_struct *mm)
{
struct mmu_gather *tlb;
- struct vm_area_struct *vma = mm->mmap;
+ struct vm_area_struct *vma;
unsigned long nr_accounted = 0;
unsigned long end;
/* mm's last user has gone, and its about to be pulled down */
arch_exit_mmap(mm);
+ if (mm->locked_vm) {
+ vma = mm->mmap;
+ while (vma) {
+ if (vma->vm_flags & VM_LOCKED)
+ munlock_vma_pages_all(vma);
+ vma = vma->vm_next;
+ }
+ }
+
+ vma = mm->mmap;
+
+
lru_add_drain();
flush_cache_mm(mm);
tlb = tlb_gather_mmu(mm, 1);
Index: linux-2.6.26-rc5-mm2/mm/mremap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mremap.c 2008-06-10 22:27:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mremap.c 2008-06-10 22:28:19.000000000 -0400
@@ -23,6 +23,8 @@
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
+#include "internal.h"
+
static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
@@ -232,8 +234,8 @@ static unsigned long move_vma(struct vm_
if (vm_flags & VM_LOCKED) {
mm->locked_vm += new_len >> PAGE_SHIFT;
if (new_len > old_len)
- make_pages_present(new_addr + old_len,
- new_addr + new_len);
+ mlock_vma_pages_range(new_vma, new_addr + old_len,
+ new_addr + new_len);
}
return new_addr;
@@ -373,7 +375,7 @@ unsigned long do_mremap(unsigned long ad
vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages);
if (vma->vm_flags & VM_LOCKED) {
mm->locked_vm += pages;
- make_pages_present(addr + old_len,
+ mlock_vma_pages_range(vma, addr + old_len,
addr + new_len);
}
ret = addr;
Index: linux-2.6.26-rc5-mm2/mm/truncate.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/truncate.c 2008-06-10 22:27:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/truncate.c 2008-06-10 22:28:19.000000000 -0400
@@ -18,6 +18,7 @@
#include <linux/task_io_accounting_ops.h>
#include <linux/buffer_head.h> /* grr. try_to_release_page,
do_invalidatepage */
+#include "internal.h"
/**
@@ -104,6 +105,7 @@ truncate_complete_page(struct address_sp
cancel_dirty_page(page, PAGE_CACHE_SIZE);
remove_from_page_cache(page);
+ clear_page_mlock(page);
ClearPageUptodate(page);
ClearPageMappedToDisk(page);
page_cache_release(page); /* pagecache ref */
@@ -128,6 +130,7 @@ invalidate_complete_page(struct address_
if (PagePrivate(page) && !try_to_release_page(page, 0))
return 0;
+ clear_page_mlock(page);
ret = remove_mapping(mapping, page);
return ret;
@@ -353,6 +356,7 @@ invalidate_complete_page2(struct address
if (PageDirty(page))
goto failed;
+ clear_page_mlock(page);
BUG_ON(PagePrivate(page));
__remove_from_page_cache(page);
write_unlock_irq(&mapping->tree_lock);
Index: linux-2.6.26-rc5-mm2/mm/mlock.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mlock.c 2008-06-10 22:28:05.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mlock.c 2008-06-10 22:28:19.000000000 -0400
@@ -270,7 +270,8 @@ static void __munlock_vma_pages_range(st
struct munlock_page_walk mpw;
VM_BUG_ON(start & ~PAGE_MASK || end & ~PAGE_MASK);
- VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem));
+ VM_BUG_ON((!rwsem_is_locked(&vma->vm_mm->mmap_sem)) &&
+ (atomic_read(&mm->mm_users) != 0));
VM_BUG_ON(start < vma->vm_start);
VM_BUG_ON(end > vma->vm_end);
@@ -351,12 +352,13 @@ no_mlock:
/*
- * munlock all pages in vma. For munmap() and exit().
+ * munlock all pages in the vma range. For mremap(), munmap() and exit().
*/
-void munlock_vma_pages_all(struct vm_area_struct *vma)
+void munlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
{
vma->vm_flags &= ~VM_LOCKED;
- __munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
+ __munlock_vma_pages_range(vma, start, end);
}
/*
Index: linux-2.6.26-rc5-mm2/mm/fremap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/fremap.c 2008-06-10 22:27:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/fremap.c 2008-06-10 22:28:19.000000000 -0400
@@ -20,6 +20,8 @@
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
+#include "internal.h"
+
static void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
{
@@ -214,13 +216,29 @@ asmlinkage long sys_remap_file_pages(uns
spin_unlock(&mapping->i_mmap_lock);
}
+ if (vma->vm_flags & VM_LOCKED) {
+ /*
+ * drop PG_Mlocked flag for over-mapped range
+ */
+ unsigned int saved_flags = vma->vm_flags;
+ munlock_vma_pages_range(vma, start, start + size);
+ vma->vm_flags = saved_flags;
+ }
+
err = populate_range(mm, vma, start, size, pgoff);
if (!err && !(flags & MAP_NONBLOCK)) {
- if (unlikely(has_write_lock)) {
- downgrade_write(&mm->mmap_sem);
- has_write_lock = 0;
+ if (vma->vm_flags & VM_LOCKED) {
+ /*
+ * might be mapping previously unmapped range of file
+ */
+ mlock_vma_pages_range(vma, start, start + size);
+ } else {
+ if (unlikely(has_write_lock)) {
+ downgrade_write(&mm->mmap_sem);
+ has_write_lock = 0;
+ }
+ make_pages_present(start, start+size);
}
- make_pages_present(start, start+size);
}
/*
Index: linux-2.6.26-rc5-mm2/mm/internal.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/internal.h 2008-06-10 22:27:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/internal.h 2008-06-10 22:28:19.000000000 -0400
@@ -63,7 +63,12 @@ static inline unsigned long page_order(s
extern int mlock_vma_pages_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end);
-extern void munlock_vma_pages_all(struct vm_area_struct *vma);
+extern void munlock_vma_pages_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end);
+static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
+{
+ munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
+}
#ifdef CONFIG_UNEVICTABLE_LRU
/*
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 19/24] vmstat: mlocked pages statistics
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (17 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 18/24] mmap: handle mlocked pages during map, remap, unmap Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 20/24] swap: cull unevictable pages in fault path Rik van Riel
` (5 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, Nick Piggin
[-- Attachment #1: vmscan-mlocked-pages-statistics.patch --]
[-- Type: text/plain, Size: 7589 bytes --]
From: Nick Piggin <npiggin@suse.de>
Add NR_MLOCK zone page state, which provides a (conservative) count of
mlocked pages (actually, the number of mlocked pages moved off the LRU).
Reworked by lts to fit in with the modified mlock page support in the
Reclaim Scalability series.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
V2 -> V3:
+ rebase to 23-mm1 atop RvR's split lru series
+ fix definitions of NR_MLOCK to fix build errors when not configured.
V1 -> V2:
+ new in V2 -- pulled in & reworked from Nick's previous series
drivers/base/node.c | 22 ++++++++++++----------
fs/proc/proc_misc.c | 2 ++
include/linux/mmzone.h | 2 ++
mm/internal.h | 14 +++++++++++---
mm/mlock.c | 24 +++++++++++++++++++-----
mm/vmstat.c | 1 +
6 files changed, 47 insertions(+), 18 deletions(-)
Index: linux-2.6.26-rc5-mm2/drivers/base/node.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/drivers/base/node.c 2008-06-10 22:37:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/drivers/base/node.c 2008-06-10 22:38:44.000000000 -0400
@@ -68,7 +68,8 @@ static ssize_t node_read_meminfo(struct
"Node %d Active(file): %8lu kB\n"
"Node %d Inactive(file): %8lu kB\n"
#ifdef CONFIG_UNEVICTABLE_LRU
- "Node %d Noreclaim: %8lu kB\n"
+ "Node %d Unevictable: %8lu kB\n"
+ "Node %d Mlocked: %8lu kB\n"
#endif
#ifdef CONFIG_HIGHMEM
"Node %d HighTotal: %8lu kB\n"
@@ -91,16 +92,17 @@ static ssize_t node_read_meminfo(struct
nid, K(i.totalram),
nid, K(i.freeram),
nid, K(i.totalram - i.freeram),
- nid, node_page_state(nid, NR_ACTIVE_ANON) +
- node_page_state(nid, NR_ACTIVE_FILE),
- nid, node_page_state(nid, NR_INACTIVE_ANON) +
- node_page_state(nid, NR_INACTIVE_FILE),
- nid, node_page_state(nid, NR_ACTIVE_ANON),
- nid, node_page_state(nid, NR_INACTIVE_ANON),
- nid, node_page_state(nid, NR_ACTIVE_FILE),
- nid, node_page_state(nid, NR_INACTIVE_FILE),
+ nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
+ node_page_state(nid, NR_ACTIVE_FILE)),
+ nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
+ node_page_state(nid, NR_INACTIVE_FILE)),
+ nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
+ nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
+ nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
+ nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
#ifdef CONFIG_UNEVICTABLE_LRU
- nid, node_page_state(nid, NR_UNEVICTABLE),
+ nid, K(node_page_state(nid, NR_UNEVICTABLE)),
+ nid, K(node_page_state(nid, NR_MLOCK)),
#endif
#ifdef CONFIG_HIGHMEM
nid, K(i.totalhigh),
Index: linux-2.6.26-rc5-mm2/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/fs/proc/proc_misc.c 2008-06-10 22:36:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/fs/proc/proc_misc.c 2008-06-10 22:37:34.000000000 -0400
@@ -177,6 +177,7 @@ static int meminfo_read_proc(char *page,
"Inactive(file): %8lu kB\n"
#ifdef CONFIG_UNEVICTABLE_LRU
"Unevictable: %8lu kB\n"
+ "Mlocked: %8lu kB\n"
#endif
#ifdef CONFIG_HIGHMEM
"HighTotal: %8lu kB\n"
@@ -215,6 +216,7 @@ static int meminfo_read_proc(char *page,
K(pages[LRU_INACTIVE_FILE]),
#ifdef CONFIG_UNEVICTABLE_LRU
K(pages[LRU_UNEVICTABLE]),
+ K(pages[NR_MLOCK]),
#endif
#ifdef CONFIG_HIGHMEM
K(i.totalhigh),
Index: linux-2.6.26-rc5-mm2/include/linux/mmzone.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/mmzone.h 2008-06-10 22:36:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/mmzone.h 2008-06-10 22:37:34.000000000 -0400
@@ -88,8 +88,10 @@ enum zone_stat_item {
NR_ACTIVE_FILE, /* " " " " " */
#ifdef CONFIG_UNEVICTABLE_LRU
NR_UNEVICTABLE, /* " " " " " */
+ NR_MLOCK, /* mlock()ed pages found and moved off LRU */
#else
NR_UNEVICTABLE = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */
+ NR_MLOCK = NR_ACTIVE_FILE,
#endif
NR_ANON_PAGES, /* Mapped anonymous pages */
NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
Index: linux-2.6.26-rc5-mm2/mm/mlock.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mlock.c 2008-06-10 22:37:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mlock.c 2008-06-10 22:37:34.000000000 -0400
@@ -56,6 +56,7 @@ void __clear_page_mlock(struct page *pag
{
VM_BUG_ON(!PageLocked(page)); /* for LRU isolate/putback */
+ dec_zone_page_state(page, NR_MLOCK);
if (!isolate_lru_page(page)) {
putback_lru_page(page);
} else {
@@ -76,8 +77,11 @@ void mlock_vma_page(struct page *page)
{
BUG_ON(!PageLocked(page));
- if (!TestSetPageMlocked(page) && !isolate_lru_page(page))
- putback_lru_page(page);
+ if (!TestSetPageMlocked(page)) {
+ inc_zone_page_state(page, NR_MLOCK);
+ if (!isolate_lru_page(page))
+ putback_lru_page(page);
+ }
}
/*
@@ -102,9 +106,19 @@ static void munlock_vma_page(struct page
{
BUG_ON(!PageLocked(page));
- if (TestClearPageMlocked(page) && !isolate_lru_page(page)) {
- try_to_munlock(page);
- putback_lru_page(page);
+ if (TestClearPageMlocked(page)) {
+ dec_zone_page_state(page, NR_MLOCK);
+ if (!isolate_lru_page(page)) {
+ try_to_munlock(page); /* maybe relock the page */
+ putback_lru_page(page);
+ }
+ /*
+ * Else we lost the race. let try_to_unmap() deal with it.
+ * At least we get the page state and mlock stats right.
+ * However, page is still on the noreclaim list. We'll fix
+ * that up when the page is eventually freed or we scan the
+ * noreclaim list.
+ */
}
}
Index: linux-2.6.26-rc5-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmstat.c 2008-06-10 22:36:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmstat.c 2008-06-10 22:37:34.000000000 -0400
@@ -608,6 +608,7 @@ static const char * const vmstat_text[]
"nr_active_file",
#ifdef CONFIG_UNEVICTABLE_LRU
"nr_unevictable",
+ "nr_mlock",
#endif
"nr_anon_pages",
"nr_mapped",
Index: linux-2.6.26-rc5-mm2/mm/internal.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/internal.h 2008-06-10 22:37:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/internal.h 2008-06-10 22:37:34.000000000 -0400
@@ -101,7 +101,8 @@ static inline int is_mlocked_vma(struct
if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
return 0;
- SetPageMlocked(page);
+ if (!TestSetPageMlocked(page))
+ inc_zone_page_state(page, NR_MLOCK);
return 1;
}
@@ -128,12 +129,19 @@ static inline void clear_page_mlock(stru
/*
* mlock_migrate_page - called only from migrate_page_copy() to
- * migrate the Mlocked page flag
+ * migrate the Mlocked page flag; update statistics.
*/
static inline void mlock_migrate_page(struct page *newpage, struct page *page)
{
- if (TestClearPageMlocked(page))
+ if (TestClearPageMlocked(page)) {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __dec_zone_page_state(page, NR_MLOCK);
SetPageMlocked(newpage);
+ __inc_zone_page_state(newpage, NR_MLOCK);
+ local_irq_restore(flags);
+ }
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 20/24] swap: cull unevictable pages in fault path
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (18 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 19/24] vmstat: mlocked pages statistics Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 21/24] vmstat: unevictable and mlocked pages vm events Rik van Riel
` (4 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, linux-mm, Eric Whitney
[-- Attachment #1: vmscan-cull-non-reclaimable-pages-in-fault-path.patch --]
[-- Type: text/plain, Size: 6183 bytes --]
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
In the fault paths that install new anonymous pages, check whether
the page is evictable or not using lru_cache_add_active_or_unevictable().
If the page is evictable, just add it to the active lru list [via
the pagevec cache], else add it to the unevictable list.
This "proactive" culling in the fault path mimics the handling of
mlocked pages in Nick Piggin's series to keep mlocked pages off
the lru lists.
Notes:
1) This patch is optional--e.g., if one is concerned about the
additional test in the fault path. We can defer the moving of
nonreclaimable pages until when vmscan [shrink_*_list()]
encounters them. Vmscan will only need to handle such pages
once, but if there are a lot of them it could impact system
performance.
2) The 'vma' argument to page_evictable() is require to notice that
we're faulting a page into an mlock()ed vma w/o having to scan the
page's rmap in the fault path. Culling mlock()ed anon pages is
currently the only reason for this patch.
3) We can't cull swap pages in read_swap_cache_async() because the
vma argument doesn't necessarily correspond to the swap cache
offset passed in by swapin_readahead(). This could [did!] result
in mlocking pages in non-VM_LOCKED vmas if [when] we tried to
cull in this path.
4) Move set_pte_at() to after where we add page to lru to keep it
hidden from other tasks that might walk the page table.
We already do it in this order in do_anonymous() page. And,
these are COW'd anon pages. Is this safe?
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
V2 -> V3:
+ rebase to 23-mm1 atop RvR's split lru series.
V1 -> V2:
+ no changes
include/linux/swap.h | 2 ++
mm/memory.c | 20 ++++++++++++--------
mm/swap.c | 21 +++++++++++++++++++++
3 files changed, 35 insertions(+), 8 deletions(-)
Index: linux-2.6.26-rc5-mm2/mm/memory.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/memory.c 2008-06-10 22:21:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/memory.c 2008-06-10 22:21:16.000000000 -0400
@@ -1813,12 +1813,15 @@ gotten:
* thread doing COW.
*/
ptep_clear_flush(vma, address, page_table);
- set_pte_at(mm, address, page_table, entry);
- update_mmu_cache(vma, address, entry);
+
SetPageSwapBacked(new_page);
- lru_cache_add_active_anon(new_page);
+ lru_cache_add_active_or_unevictable(new_page, vma);
page_add_new_anon_rmap(new_page, vma, address);
+//TODO: is this safe? do_anonymous_page() does it this way.
+ set_pte_at(mm, address, page_table, entry);
+ update_mmu_cache(vma, address, entry);
+
/* Free the old page.. */
new_page = old_page;
ret |= VM_FAULT_WRITE;
@@ -2285,7 +2288,7 @@ static int do_anonymous_page(struct mm_s
goto release;
inc_mm_counter(mm, anon_rss);
SetPageSwapBacked(page);
- lru_cache_add_active_anon(page);
+ lru_cache_add_active_or_unevictable(page, vma);
page_add_new_anon_rmap(page, vma, address);
set_pte_at(mm, address, page_table, entry);
@@ -2429,12 +2432,11 @@ static int __do_fault(struct mm_struct *
entry = mk_pte(page, vma->vm_page_prot);
if (flags & FAULT_FLAG_WRITE)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- set_pte_at(mm, address, page_table, entry);
if (anon) {
- inc_mm_counter(mm, anon_rss);
+ inc_mm_counter(mm, anon_rss);
SetPageSwapBacked(page);
- lru_cache_add_active_anon(page);
- page_add_new_anon_rmap(page, vma, address);
+ lru_cache_add_active_or_unevictable(page, vma);
+ page_add_new_anon_rmap(page, vma, address);
} else {
inc_mm_counter(mm, file_rss);
page_add_file_rmap(page);
@@ -2443,6 +2445,8 @@ static int __do_fault(struct mm_struct *
get_page(dirty_page);
}
}
+//TODO: is this safe? do_anonymous_page() does it this way.
+ set_pte_at(mm, address, page_table, entry);
/* no need to invalidate: a not-present page won't be cached */
update_mmu_cache(vma, address, entry);
Index: linux-2.6.26-rc5-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/swap.h 2008-06-10 22:21:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/swap.h 2008-06-10 22:24:12.000000000 -0400
@@ -173,6 +173,8 @@ extern unsigned int nr_free_pagecache_pa
/* linux/mm/swap.c */
extern void __lru_cache_add(struct page *, enum lru_list lru);
extern void lru_cache_add_lru(struct page *, enum lru_list lru);
+extern void lru_cache_add_active_or_unevictable(struct page *,
+ struct vm_area_struct *);
extern void activate_page(struct page *);
extern void mark_page_accessed(struct page *);
extern void lru_add_drain(void);
Index: linux-2.6.26-rc5-mm2/mm/swap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/swap.c 2008-06-10 22:21:14.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/swap.c 2008-06-10 22:21:16.000000000 -0400
@@ -31,6 +31,8 @@
#include <linux/backing-dev.h>
#include <linux/memcontrol.h>
+#include "internal.h"
+
/* How many pages do we try to swap or page in/out together? */
int page_cluster;
@@ -244,6 +246,25 @@ void add_page_to_unevictable_list(struct
spin_unlock_irq(&zone->lru_lock);
}
+/**
+ * lru_cache_add_active_or_unevictable
+ * @page: the page to be added to LRU
+ * @vma: vma in which page is mapped for determining reclaimability
+ *
+ * place @page on active or unevictable LRU list, depending on
+ * page_evictable(). Note that if the page is not evictable,
+ * it goes directly back onto it's zone's unevictable list. It does
+ * NOT use a per cpu pagevec.
+ */
+void lru_cache_add_active_or_unevictable(struct page *page,
+ struct vm_area_struct *vma)
+{
+ if (page_evictable(page, vma))
+ lru_cache_add_lru(page, page_lru(page));
+ else
+ add_page_to_unevictable_list(page);
+}
+
/*
* Drain pages out of the cpu's pagevecs.
* Either "cpu" is the current CPU, and preemption has already been
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 21/24] vmstat: unevictable and mlocked pages vm events
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (19 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 20/24] swap: cull unevictable pages in fault path Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 22/24] vmscan: unevictable LRU scan sysctl Rik van Riel
` (3 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-noreclaim-and-mlocked-pages-vm-events.patch --]
[-- Type: text/plain, Size: 7183 bytes --]
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
Add some event counters to vmstats for testing unevictable/mlock.
Some of these might be interesting enough to keep around.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
include/linux/vmstat.h | 9 +++++++++
mm/internal.h | 4 +++-
mm/mlock.c | 33 +++++++++++++++++++++++++--------
mm/vmscan.c | 16 +++++++++++++++-
mm/vmstat.c | 10 ++++++++++
5 files changed, 62 insertions(+), 10 deletions(-)
Index: linux-2.6.26-rc5-mm2/include/linux/vmstat.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/vmstat.h 2008-06-10 22:23:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/vmstat.h 2008-06-10 22:25:48.000000000 -0400
@@ -41,6 +41,15 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
#ifdef CONFIG_HUGETLB_PAGE
HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
#endif
+#ifdef CONFIG_UNEVICTABLE_LRU
+ NORECL_PGCULLED, /* culled to noreclaim list */
+ NORECL_PGSCANNED, /* scanned for reclaimability */
+ NORECL_PGRESCUED, /* rescued from noreclaim list */
+ NORECL_PGMLOCKED,
+ NORECL_PGMUNLOCKED,
+ NORECL_PGCLEARED,
+ NORECL_PGSTRANDED, /* unable to isolate on unlock */
+#endif
NR_VM_EVENT_ITEMS
};
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 22:23:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 22:25:49.000000000 -0400
@@ -468,12 +468,13 @@ int putback_lru_page(struct page *page)
{
int lru;
int ret = 1;
+ int was_unevictable;
VM_BUG_ON(!PageLocked(page));
VM_BUG_ON(PageLRU(page));
lru = !!TestClearPageActive(page);
- ClearPageUnevictable(page); /* for page_evictable() */
+ was_unevictable = TestClearPageUnevictable(page); /* for page_evictable() */
if (unlikely(!page->mapping)) {
/*
@@ -493,6 +494,10 @@ int putback_lru_page(struct page *page)
lru += page_is_file_cache(page);
lru_cache_add_lru(page, lru);
mem_cgroup_move_lists(page, lru);
+#ifdef CONFIG_UNEVICTABLE_LRU
+ if (was_unevictable)
+ count_vm_event(NORECL_PGRESCUED);
+#endif
} else {
/*
* Put unevictable pages directly on zone's unevictable
@@ -500,6 +505,10 @@ int putback_lru_page(struct page *page)
*/
add_page_to_unevictable_list(page);
mem_cgroup_move_lists(page, LRU_UNEVICTABLE);
+#ifdef CONFIG_UNEVICTABLE_LRU
+ if (!was_unevictable)
+ count_vm_event(NORECL_PGCULLED);
+#endif
}
put_page(page); /* drop ref from isolate */
@@ -2373,6 +2382,7 @@ static void check_move_unevictable_page(
__dec_zone_state(zone, NR_UNEVICTABLE);
list_move(&page->lru, &zone->lru[l].list);
__inc_zone_state(zone, NR_INACTIVE_ANON + l);
+ __count_vm_event(NORECL_PGRESCUED);
} else {
/*
* rotate unevictable list
@@ -2404,6 +2414,7 @@ void scan_mapping_unevictable_pages(stru
while (next < end &&
pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
int i;
+ int pg_scanned = 0;
zone = NULL;
@@ -2412,6 +2423,7 @@ void scan_mapping_unevictable_pages(stru
pgoff_t page_index = page->index;
struct zone *pagezone = page_zone(page);
+ pg_scanned++;
if (page_index > next)
next = page_index;
next++;
@@ -2442,6 +2454,8 @@ void scan_mapping_unevictable_pages(stru
if (zone)
spin_unlock_irq(&zone->lru_lock);
pagevec_release(&pvec);
+
+ count_vm_events(NORECL_PGSCANNED, pg_scanned);
}
}
Index: linux-2.6.26-rc5-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmstat.c 2008-06-10 22:23:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmstat.c 2008-06-10 22:25:48.000000000 -0400
@@ -664,6 +664,16 @@ static const char * const vmstat_text[]
"htlb_buddy_alloc_success",
"htlb_buddy_alloc_fail",
#endif
+
+#ifdef CONFIG_UNEVICTABLE_LRU
+ "noreclaim_pgs_culled",
+ "noreclaim_pgs_scanned",
+ "noreclaim_pgs_rescued",
+ "noreclaim_pgs_mlocked",
+ "noreclaim_pgs_munlocked",
+ "noreclaim_pgs_cleared",
+ "noreclaim_pgs_stranded",
+#endif
#endif
};
Index: linux-2.6.26-rc5-mm2/mm/mlock.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/mlock.c 2008-06-10 22:23:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/mlock.c 2008-06-10 22:25:56.000000000 -0400
@@ -18,6 +18,7 @@
#include <linux/rmap.h>
#include <linux/mmzone.h>
#include <linux/hugetlb.h>
+#include <linux/vmstat.h>
#include "internal.h"
@@ -57,6 +58,7 @@ void __clear_page_mlock(struct page *pag
VM_BUG_ON(!PageLocked(page)); /* for LRU isolate/putback */
dec_zone_page_state(page, NR_MLOCK);
+ count_vm_event(NORECL_PGCLEARED);
if (!isolate_lru_page(page)) {
putback_lru_page(page);
} else {
@@ -66,6 +68,8 @@ void __clear_page_mlock(struct page *pag
lru_add_drain_all();
if (!isolate_lru_page(page))
putback_lru_page(page);
+ else if (PageUnevictable(page))
+ count_vm_event(NORECL_PGSTRANDED);
}
}
@@ -79,6 +83,7 @@ void mlock_vma_page(struct page *page)
if (!TestSetPageMlocked(page)) {
inc_zone_page_state(page, NR_MLOCK);
+ count_vm_event(NORECL_PGMLOCKED);
if (!isolate_lru_page(page))
putback_lru_page(page);
}
@@ -109,16 +114,28 @@ static void munlock_vma_page(struct page
if (TestClearPageMlocked(page)) {
dec_zone_page_state(page, NR_MLOCK);
if (!isolate_lru_page(page)) {
- try_to_munlock(page); /* maybe relock the page */
+ int ret = try_to_munlock(page);
+ /*
+ * did try_to_unlock() succeed or punt?
+ */
+ if (ret == SWAP_SUCCESS || ret == SWAP_AGAIN)
+ count_vm_event(NORECL_PGMUNLOCKED);
+
putback_lru_page(page);
+ } else {
+ /*
+ * We lost the race. let try_to_unmap() deal
+ * with it. At least we get the page state and
+ * mlock stats right. However, page is still on
+ * the noreclaim list. We'll fix that up when
+ * the page is eventually freed or we scan the
+ * noreclaim list.
+ */
+ if (PageUnevictable(page))
+ count_vm_event(NORECL_PGSTRANDED);
+ else
+ count_vm_event(NORECL_PGMUNLOCKED);
}
- /*
- * Else we lost the race. let try_to_unmap() deal with it.
- * At least we get the page state and mlock stats right.
- * However, page is still on the noreclaim list. We'll fix
- * that up when the page is eventually freed or we scan the
- * noreclaim list.
- */
}
}
Index: linux-2.6.26-rc5-mm2/mm/internal.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/internal.h 2008-06-10 22:23:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/internal.h 2008-06-10 22:25:48.000000000 -0400
@@ -101,8 +101,10 @@ static inline int is_mlocked_vma(struct
if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
return 0;
- if (!TestSetPageMlocked(page))
+ if (!TestSetPageMlocked(page)) {
inc_zone_page_state(page, NR_MLOCK);
+ count_vm_event(NORECL_PGMLOCKED);
+ }
return 1;
}
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 22/24] vmscan: unevictable LRU scan sysctl
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (20 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 21/24] vmstat: unevictable and mlocked pages vm events Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 23/24] mlock: count attempts to free mlocked page Rik van Riel
` (2 subsequent siblings)
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, linux-mm, Eric Whitney
[-- Attachment #1: mm-only-vmscan-noreclaim-lru-scan-sysctl.patch --]
[-- Type: text/plain, Size: 11578 bytes --]
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
This patch adds a function to scan individual or all zones' unevictable
lists and move any pages that have become evictable onto the respective
zone's inactive list, where shrink_inactive_list() will deal with them.
Adds sysctl to scan all nodes, and per node attributes to individual
nodes' zones.
Kosaki:
If evictable page found in unevictable lru when write
/proc/sys/vm/scan_unevictable_pages, print filename and file offset of
these pages.
---
TODO: DEBUGGING ONLY: NOT FOR UPSTREAM MERGE
V6:
+ moved to end of series as optional debug patch
V2 -> V3:
+ rebase to 23-mm1 atop RvR's split LRU series
New in V2
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
drivers/base/node.c | 5 +
include/linux/rmap.h | 3
include/linux/swap.h | 15 ++++
kernel/sysctl.c | 10 +++
mm/rmap.c | 4 -
mm/vmscan.c | 163 +++++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 198 insertions(+), 2 deletions(-)
Index: linux-2.6.26-rc5-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/swap.h 2008-06-10 22:38:56.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/swap.h 2008-06-10 22:38:58.000000000 -0400
@@ -7,6 +7,7 @@
#include <linux/list.h>
#include <linux/memcontrol.h>
#include <linux/sched.h>
+#include <linux/node.h>
#include <asm/atomic.h>
#include <asm/page.h>
@@ -235,15 +236,29 @@ static inline int zone_reclaim(struct zo
#ifdef CONFIG_UNEVICTABLE_LRU
extern int page_evictable(struct page *page, struct vm_area_struct *vma);
extern void scan_mapping_unevictable_pages(struct address_space *);
+
+extern unsigned long scan_unevictable_pages;
+extern int scan_unevictable_handler(struct ctl_table *, int, struct file *,
+ void __user *, size_t *, loff_t *);
+extern int scan_unevictable_register_node(struct node *node);
+extern void scan_unevictable_unregister_node(struct node *node);
#else
static inline int page_evictable(struct page *page,
struct vm_area_struct *vma)
{
return 1;
}
+
static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
{
}
+
+static inline int scan_unevictable_register_node(struct node *node)
+{
+ return 0;
+}
+
+static inline void scan_unevictable_unregister_node(struct node *node) { }
#endif
extern int kswapd_run(int nid);
Index: linux-2.6.26-rc5-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmscan.c 2008-06-10 22:38:57.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmscan.c 2008-06-10 23:02:07.000000000 -0400
@@ -39,6 +39,7 @@
#include <linux/freezer.h>
#include <linux/memcontrol.h>
#include <linux/delayacct.h>
+#include <linux/sysctl.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -2362,6 +2363,39 @@ int page_evictable(struct page *page, st
return 1;
}
+static void show_page_path(struct page *page)
+{
+ char buf[256];
+ if (page_is_file_cache(page)) {
+ struct address_space *mapping = page->mapping;
+ struct dentry *dentry;
+ pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+
+ spin_lock(&mapping->i_mmap_lock);
+ dentry = d_find_alias(mapping->host);
+ printk(KERN_INFO "rescued: %s %lu\n",
+ dentry_path(dentry, buf, 256), pgoff);
+ spin_unlock(&mapping->i_mmap_lock);
+ } else {
+#ifdef CONFIG_MM_OWNER
+ struct anon_vma *anon_vma;
+ struct vm_area_struct *vma;
+
+ anon_vma = page_lock_anon_vma(page);
+ if (!anon_vma)
+ return;
+
+ list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
+ printk(KERN_INFO "rescued: anon %s\n",
+ vma->vm_mm->owner->comm);
+ break;
+ }
+ page_unlock_anon_vma(anon_vma);
+#endif
+ }
+}
+
+
/**
* check_move_unevictable_page - check page for evictability and move to appropriate zone lru list
* @page: page to check evictability and move to appropriate lru list
@@ -2379,6 +2413,9 @@ static void check_move_unevictable_page(
ClearPageUnevictable(page); /* for page_evictable() */
if (page_evictable(page, NULL)) {
enum lru_list l = LRU_INACTIVE_ANON + page_is_file_cache(page);
+
+ show_page_path(page);
+
__dec_zone_state(zone, NR_UNEVICTABLE);
list_move(&page->lru, &zone->lru[l].list);
__inc_zone_state(zone, NR_INACTIVE_ANON + l);
@@ -2459,4 +2496,130 @@ void scan_mapping_unevictable_pages(stru
}
}
+
+/**
+ * scan_zone_unevictable_pages - check unevictable list for evictable pages
+ * @zone - zone of which to scan the unevictable list
+ *
+ * Scan @zone's unevictable LRU lists to check for pages that have become
+ * evictable. Move those that have to @zone's inactive list where they
+ * become candidates for reclaim, unless shrink_inactive_zone() decides
+ * to reactivate them. Pages that are still unevictable are rotated
+ * back onto @zone's unevictable list.
+ */
+#define SCAN_UNEVICTABLE_BATCH_SIZE 16UL /* arbitrary lock hold batch size */
+void scan_zone_unevictable_pages(struct zone *zone)
+{
+ struct list_head *l_unevictable = &zone->lru[LRU_UNEVICTABLE].list;
+ unsigned long scan;
+ unsigned long nr_to_scan = zone_page_state(zone, NR_UNEVICTABLE);
+
+ while (nr_to_scan > 0) {
+ unsigned long batch_size = min(nr_to_scan,
+ SCAN_UNEVICTABLE_BATCH_SIZE);
+
+ spin_lock_irq(&zone->lru_lock);
+ for (scan = 0; scan < batch_size; scan++) {
+ struct page *page = lru_to_page(l_unevictable);
+
+ if (TestSetPageLocked(page))
+ continue;
+
+ prefetchw_prev_lru_page(page, l_unevictable, flags);
+
+ if (likely(PageLRU(page) && PageUnevictable(page)))
+ check_move_unevictable_page(page, zone);
+
+ unlock_page(page);
+ }
+ spin_unlock_irq(&zone->lru_lock);
+
+ nr_to_scan -= batch_size;
+ }
+}
+
+
+/**
+ * scan_all_zones_unevictable_pages - scan all unevictable lists for evictable pages
+ *
+ * A really big hammer: scan all zones' unevictable LRU lists to check for
+ * pages that have become evictable. Move those back to the zones'
+ * inactive list where they become candidates for reclaim.
+ * This occurs when, e.g., we have unswappable pages on the unevictable lists,
+ * and we add swap to the system. As such, it runs in the context of a task
+ * that has possibly/probably made some previously unevictable pages
+ * evictable.
+ */
+void scan_all_zones_unevictable_pages(void)
+{
+ struct zone *zone;
+
+ for_each_zone(zone) {
+ scan_zone_unevictable_pages(zone);
+ }
+}
+
+/*
+ * scan_unevictable_pages [vm] sysctl handler. On demand re-scan of
+ * all nodes' unevictable lists for evictable pages
+ */
+unsigned long scan_unevictable_pages;
+
+int scan_unevictable_handler(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+
+ if (write && *(unsigned long *)table->data)
+ scan_all_zones_unevictable_pages();
+
+ scan_unevictable_pages = 0;
+ return 0;
+}
+
+/*
+ * per node 'scan_unevictable_pages' attribute. On demand re-scan of
+ * a specified node's per zone unevictable lists for evictable pages.
+ */
+
+static ssize_t read_scan_unevictable_node(struct sys_device *dev, char *buf)
+{
+ return sprintf(buf, "0\n"); /* always zero; should fit... */
+}
+
+static ssize_t write_scan_unevictable_node(struct sys_device *dev,
+ const char *buf, size_t count)
+{
+ struct zone *node_zones = NODE_DATA(dev->id)->node_zones;
+ struct zone *zone;
+ unsigned long res;
+ unsigned long req = strict_strtoul(buf, 10, &res);
+
+ if (!req)
+ return 1; /* zero is no-op */
+
+ for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
+ if (!populated_zone(zone))
+ continue;
+ scan_zone_unevictable_pages(zone);
+ }
+ return 1;
+}
+
+
+static SYSDEV_ATTR(scan_unevictable_pages, S_IRUGO | S_IWUSR,
+ read_scan_unevictable_node,
+ write_scan_unevictable_node);
+
+int scan_unevictable_register_node(struct node *node)
+{
+ return sysdev_create_file(&node->sysdev, &attr_scan_unevictable_pages);
+}
+
+void scan_unevictable_unregister_node(struct node *node)
+{
+ sysdev_remove_file(&node->sysdev, &attr_scan_unevictable_pages);
+}
+
#endif
Index: linux-2.6.26-rc5-mm2/kernel/sysctl.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/kernel/sysctl.c 2008-06-10 22:36:48.000000000 -0400
+++ linux-2.6.26-rc5-mm2/kernel/sysctl.c 2008-06-10 22:38:58.000000000 -0400
@@ -1141,6 +1141,16 @@ static struct ctl_table vm_table[] = {
.extra2 = &one,
},
#endif
+#ifdef CONFIG_UNEVICTABLE_LRU
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "scan_unevictable_pages",
+ .data = &scan_unevictable_pages,
+ .maxlen = sizeof(scan_unevictable_pages),
+ .mode = 0644,
+ .proc_handler = &scan_unevictable_handler,
+ },
+#endif
/*
* NOTE: do not add new entries to this table unless you have read
* Documentation/sysctl/ctl_unnumbered.txt
Index: linux-2.6.26-rc5-mm2/drivers/base/node.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/drivers/base/node.c 2008-06-10 22:38:44.000000000 -0400
+++ linux-2.6.26-rc5-mm2/drivers/base/node.c 2008-06-10 22:38:58.000000000 -0400
@@ -13,6 +13,7 @@
#include <linux/nodemask.h>
#include <linux/cpu.h>
#include <linux/device.h>
+#include <linux/swap.h>
static struct sysdev_class node_class = {
.name = "node",
@@ -186,6 +187,8 @@ int register_node(struct node *node, int
sysdev_create_file(&node->sysdev, &attr_meminfo);
sysdev_create_file(&node->sysdev, &attr_numastat);
sysdev_create_file(&node->sysdev, &attr_distance);
+
+ scan_unevictable_register_node(node);
}
return error;
}
@@ -205,6 +208,8 @@ void unregister_node(struct node *node)
sysdev_remove_file(&node->sysdev, &attr_numastat);
sysdev_remove_file(&node->sysdev, &attr_distance);
+ scan_unevictable_unregister_node(node);
+
sysdev_unregister(&node->sysdev);
}
Index: linux-2.6.26-rc5-mm2/include/linux/rmap.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/rmap.h 2008-06-10 22:37:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/rmap.h 2008-06-10 22:38:58.000000000 -0400
@@ -67,6 +67,9 @@ void anon_vma_unlink(struct vm_area_stru
void anon_vma_link(struct vm_area_struct *);
void __anon_vma_link(struct vm_area_struct *);
+extern struct anon_vma *page_lock_anon_vma(struct page *page);
+extern void page_unlock_anon_vma(struct anon_vma *anon_vma);
+
/*
* rmap interfaces called when adding or removing pte of page
*/
Index: linux-2.6.26-rc5-mm2/mm/rmap.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/rmap.c 2008-06-10 22:37:26.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/rmap.c 2008-06-10 22:38:58.000000000 -0400
@@ -158,7 +158,7 @@ void __init anon_vma_init(void)
* Getting a lock on a stable anon_vma from a page off the LRU is
* tricky: page_lock_anon_vma rely on RCU to guard against the races.
*/
-static struct anon_vma *page_lock_anon_vma(struct page *page)
+struct anon_vma *page_lock_anon_vma(struct page *page)
{
struct anon_vma *anon_vma;
unsigned long anon_mapping;
@@ -178,7 +178,7 @@ out:
return NULL;
}
-static void page_unlock_anon_vma(struct anon_vma *anon_vma)
+void page_unlock_anon_vma(struct anon_vma *anon_vma)
{
spin_unlock(&anon_vma->lock);
rcu_read_unlock();
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 23/24] mlock: count attempts to free mlocked page
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (21 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 22/24] vmscan: unevictable LRU scan sysctl Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 24/24] doc: unevictable LRU and mlocked pages documentation Rik van Riel
2008-06-12 5:34 ` [PATCH -mm 00/24] VM pageout scalability improvements (V12) Andrew Morton
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel; +Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
[-- Attachment #1: vmscan-mlocked-pages-count-attempts-to-free-mlocked-page.patch --]
[-- Type: text/plain, Size: 3326 bytes --]
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
Allow free of mlock()ed pages. This shouldn't happen, but during
developement, it occasionally did.
This patch allows us to survive that condition, while keeping the
statistics and events correct for debug.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
include/linux/vmstat.h | 1 +
mm/internal.h | 17 +++++++++++++++++
mm/page_alloc.c | 1 +
mm/vmstat.c | 1 +
4 files changed, 20 insertions(+)
Index: linux-2.6.26-rc5-mm2/mm/internal.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/internal.h 2008-06-10 21:40:05.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/internal.h 2008-06-10 21:55:28.000000000 -0400
@@ -146,6 +146,22 @@ static inline void mlock_migrate_page(st
}
}
+/*
+ * free_page_mlock() -- clean up attempts to free and mlocked() page.
+ * Page should not be on lru, so no need to fix that up.
+ * free_pages_check() will verify...
+ */
+static inline void free_page_mlock(struct page *page)
+{
+ if (unlikely(TestClearPageMlocked(page))) {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __dec_zone_page_state(page, NR_MLOCK);
+ __count_vm_event(NORECL_MLOCKFREED);
+ local_irq_restore(flags);
+ }
+}
#else /* CONFIG_UNEVICTABLE_LRU */
static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
@@ -155,6 +171,7 @@ static inline int is_mlocked_vma(struct
static inline void clear_page_mlock(struct page *page) { }
static inline void mlock_vma_page(struct page *page) { }
static inline void mlock_migrate_page(struct page *new, struct page *old) { }
+static inline void free_page_mlock(struct page *page) { }
#endif /* CONFIG_UNEVICTABLE_LRU */
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 21:21:44.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 21:55:28.000000000 -0400
@@ -465,6 +465,7 @@ static inline void __free_one_page(struc
static inline int free_pages_check(struct page *page)
{
+ free_page_mlock(page);
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
(page_get_page_cgroup(page) != NULL) |
Index: linux-2.6.26-rc5-mm2/include/linux/vmstat.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/linux/vmstat.h 2008-06-10 21:40:05.000000000 -0400
+++ linux-2.6.26-rc5-mm2/include/linux/vmstat.h 2008-06-10 21:55:28.000000000 -0400
@@ -49,6 +49,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
NORECL_PGMUNLOCKED,
NORECL_PGCLEARED,
NORECL_PGSTRANDED, /* unable to isolate on unlock */
+ NORECL_MLOCKFREED,
#endif
NR_VM_EVENT_ITEMS
};
Index: linux-2.6.26-rc5-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/vmstat.c 2008-06-10 21:40:05.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/vmstat.c 2008-06-10 21:55:28.000000000 -0400
@@ -673,6 +673,7 @@ static const char * const vmstat_text[]
"noreclaim_pgs_munlocked",
"noreclaim_pgs_cleared",
"noreclaim_pgs_stranded",
+ "noreclaim_pgs_mlockfreed",
#endif
#endif
};
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH -mm 24/24] doc: unevictable LRU and mlocked pages documentation
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (22 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 23/24] mlock: count attempts to free mlocked page Rik van Riel
@ 2008-06-11 18:42 ` Rik van Riel
2008-06-12 5:34 ` [PATCH -mm 00/24] VM pageout scalability improvements (V12) Andrew Morton
24 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 18:42 UTC (permalink / raw)
To: linux-kernel
Cc: Andrew Morton, Lee Schermerhorn, Kosaki Motohiro, linux-mm, Eric Whitney
[-- Attachment #1: vmscan-noreclaim-lru-and-mlocked-pages-documentation.patch --]
[-- Type: text/plain, Size: 36042 bytes --]
From: Lee Schermerhorn <lee.schermerhorn@hp.com>
Documentation for unevictable lru list and its usage.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
Documentation/vm/unevictable-lru.txt | 609 +++++++++++++++++++++++++++++++++++
1 file changed, 609 insertions(+)
Index: linux-2.6.26-rc5-mm2/Documentation/vm/unevictable-lru.txt
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.26-rc5-mm2/Documentation/vm/unevictable-lru.txt 2008-06-10 22:05:06.000000000 -0400
@@ -0,0 +1,609 @@
+
+This document describes the Linux memory management "Unevictable LRU"
+infrastructure and the use of this infrastructure to manage several types
+of "unevictable" pages. The document attempts to provide the overall
+rationale behind this mechanism and the rationale for some of the design
+decisions that drove the implementation. The latter design rationale is
+discussed in the context of an implementation description. Admittedly, one
+can obtain the implementation details--the "what does it do?"--by reading the
+code. One hopes that the descriptions below add value by provide the answer
+to "why does it do that?".
+
+Unevictable LRU Infrastructure:
+
+The Unevictable LRU adds an additional LRU list to track unevictable pages
+and to hide these pages from vmscan. This mechanism is based on a patch by
+Larry Woodman of Red Hat to address several scalability problems with page
+reclaim in Linux. The problems have been observed at customer sites on large
+memory x86_64 systems. For example, a non-numal x86_64 platform with 128GB
+of main memory will have over 32 million 4k pages in a single zone. When a
+large fraction of these pages are not evictable for any reason [see below],
+vmscan will spend a lot of time scanning the LRU lists looking for the small
+fraction of pages that are evictable. This can result in a situation where
+all cpus are spending 100% of their time in vmscan for hours or days on end,
+with the system completely unresponsive.
+
+The Unevictable LRU infrastructure addresses the following classes of
+unevictable pages:
+
++ page owned by ram disks or ramfs
++ page mapped into SHM_LOCKed shared memory regions
++ page mapped into VM_LOCKED [mlock()ed] vmas
+
+The infrastructure might be able to handle other conditions that make pages
+unevictable, either by definition or by circumstance, in the future.
+
+
+The Unevictable LRU List
+
+The Unevictable LRU infrastructure consists of an additional, per-zone, LRU list
+called the "unevictable" list and an associated page flag, PG_unevictable, to
+indicate that the page is being managed on the unevictable list. The PG_unevictable
+flag is analogous to, and mutually exclusive with, the PG_active flag in that
+it indicates on which LRU list a page resides when PG_lru is set. The
+unevictable LRU list is source configurable based on the UNEVICTABLE_LRU Kconfig
+option.
+
+Why maintain unevictable pages on an additional LRU list? The Linux memory
+management subsystem has well established protocols for managing pages on the
+LRU. Vmscan is based on LRU lists. LRU list exist per zone, and we want to
+maintain pages relative to their "home zone". All of these make the use of
+an additional list, parallel to the LRU active and inactive lists, a natural
+mechanism to employ. Note, however, that the unevictable list does not
+differentiate between file backed and swap backed [anon] pages. This
+differentiation is only important while the pages are, in fact, evictable.
+
+The unevictable LRU list benefits from the "arrayification" of the per-zone
+LRU lists and statistics originally proposed and posted by Christoph Lameter.
+
+Note that the unevictable list does not use the lru pagevec mechanism. Rather,
+unevictable pages are placed directly on the page's zone's unevictable
+list under the zone lru_lock. The reason for this is to prevent stranding
+of pages on the unevictable list when one task has the page isolated from the
+lru and other tasks are changing the "evictability" state of the page.
+
+
+Unevictable LRU and Memory Controller Interaction
+
+The memory controller data structure automatically gets a per zone unevictable
+lru list as a result of the "arrayification" of the per-zone LRU lists. The
+memory controller tracks the movement of pages to and from the unevictable list.
+When a memory control group comes under memory pressure, the controller will
+not attempt to reclaim pages on the unevictable list. This has a couple of
+effects. Because the pages are "hidden" from reclaim on the unevictable list,
+the reclaim process can be more efficient, dealing only with pages that have
+a chance of being reclaimed. On the other hand, if too many of the pages
+charged to the control group are unevictable, the evictable portion of the
+working set of the tasks in the control group may not fit into the available
+memory. This can cause the control group to thrash or to oom-kill tasks.
+
+
+Unevictable LRU: Detecting Unevictable Pages
+
+The function page_evictable(page, vma) in vmscan.c determines whether a
+page is evictable or not. For ramfs and ram disk [brd] pages and pages in
+SHM_LOCKed regions, page_evictable() tests a new address space flag,
+AS_UNEVICTABLE, in the page's address space using a wrapper function.
+Wrapper functions are used to set, clear and test the flag to reduce the
+requirement for #ifdef's throughout the source code. AS_UNEVICTABLE is set on
+ramfs inode/mapping when it is created and on ram disk inode/mappings at open
+time. This flag remains for the life of the inode.
+
+For shared memory regions, AS_UNEVICTABLE is set when an application successfully
+SHM_LOCKs the region and is removed when the region is SHM_UNLOCKed. Note that
+shmctl(SHM_LOCK, ...) does not populate the page tables for the region as does,
+for example, mlock(). So, we make no special effort to push any pages in the
+SHM_LOCKed region to the unevictable list. Vmscan will do this when/if it
+encounters the pages during reclaim. On SHM_UNLOCK, shmctl() scans the pages
+in the region and "rescues" them from the unevictable list if no other condition
+keeps them unevictable. If a SHM_LOCKed region is destroyed, the pages
+are also "rescued" from the unevictable list in the process of freeing them.
+
+page_evictable() detects mlock()ed pages by testing an additional page flag,
+PG_mlocked via the PageMlocked() wrapper. If the page is NOT mlocked, and a
+non-NULL vma is supplied, page_evictable() will check whether the vma is
+VM_LOCKED via is_mlocked_vma(). is_mlocked_vma() will SetPageMlocked() and
+update the appropriate statistics if the vma is VM_LOCKED. This method allows
+efficient "culling" of pages in the fault path that are being faulted in to
+VM_LOCKED vmas.
+
+
+Unevictable Pages and Vmscan [shrink_*_list()]
+
+If unevictable pages are culled in the fault path, or moved to the
+unevictable list at mlock() or mmap() time, vmscan will never encounter the pages
+until they have become evictable again, for example, via munlock() and have
+been "rescued" from the unevictable list. However, there may be situations where
+we decide, for the sake of expediency, to leave a unevictable page on one of
+the regular active/inactive LRU lists for vmscan to deal with. Vmscan checks
+for such pages in all of the shrink_{active|inactive|page}_list() functions and
+will "cull" such pages that it encounters--that is, it diverts those pages to
+the unevictable list for the zone being scanned.
+
+There may be situations where a page is mapped into a VM_LOCKED vma, but the
+page is not marked as PageMlocked. Such pages will make it all the way to
+shrink_page_list() where they will be detected when vmscan walks the reverse
+map in try_to_unmap(). If try_to_unmap() returns SWAP_MLOCK, shrink_page_list()
+will cull the page at that point.
+
+Note that for anonymous pages, shrink_page_list() attempts to add the page to
+the swap cache before it tries to unmap the page. To avoid this unnecessary
+consumption of swap space, shrink_page_list() calls try_to_munlock() to check
+whether any VM_LOCKED vmas map the page without attempting to unmap the page.
+If try_to_munlock() returns SWAP_MLOCK, shrink_page_list() will cull the page
+without consuming swap space. try_to_munlock() will be described below.
+
+
+Mlocked Page: Prior Work
+
+The "Unevictable Mlocked Pages" infrastructure is based on work originally posted
+by Nick Piggin in an RFC patch entitled "mm: mlocked pages off LRU". Nick's
+posted his patch as an alternative to a patch posted by Christoph Lameter to
+achieve the same objective--hiding mlocked pages from vmscan. In Nick's patch,
+he used one of the struct page lru list link fields as a count of VM_LOCKED
+vmas that map the page. This use of the link field for a count prevent the
+management of the pages on an LRU list. When Nick's patch was integrated with
+the Unevictable LRU work, the count was replaced by walking the reverse map to
+determine whether any VM_LOCKED vmas mapped the page. More on this below.
+The primary reason for wanting to keep mlocked pages on an LRU list is that
+mlocked pages are migratable, and the LRU list is used to arbitrate tasks
+attempting to migrate the same page. Whichever task succeeds in "isolating"
+the page from the LRU performs the migration.
+
+
+Mlocked Pages: Basic Management
+
+Mlocked pages--pages mapped into a VM_LOCKED vma--represent one class of
+unevictable pages. When such a page has been "noticed" by the memory
+management subsystem, the page is marked with the PG_mlocked [PageMlocked()]
+flag. A PageMlocked() page will be placed on the unevictable LRU list when
+it is added to the LRU. Pages can be "noticed" by memory management in
+several places:
+
+1) in the mlock()/mlockall() system call handlers.
+2) in the mmap() system call handler when mmap()ing a region with the
+ MAP_LOCKED flag, or mmap()ing a region in a task that has called
+ mlockall() with the MCL_FUTURE flag. Both of these conditions result
+ in the VM_LOCKED flag being set for the vma.
+3) in the fault path, if mlocked pages are "culled" in the fault path,
+ and when a VM_LOCKED stack segment is expanded.
+4) as mentioned above, in vmscan:shrink_page_list() with attempting to
+ reclaim a page in a VM_LOCKED vma--via try_to_unmap() or try_to_munlock().
+
+Mlocked pages become unlocked and rescued from the unevictable list when:
+
+1) mapped in a range unlocked via the munlock()/munlockall() system calls.
+2) munmapped() out of the last VM_LOCKED vma that maps the page, including
+ unmapping at task exit.
+3) when the page is truncated from the last VM_LOCKED vma of an mmap()ed file.
+4) before a page is COWed in a VM_LOCKED vma.
+
+
+Mlocked Pages: mlock()/mlockall() System Call Handling
+
+Both [do_]mlock() and [do_]mlockall() system call handlers call mlock_fixup()
+for each vma in the range specified by the call. In the case of mlockall(),
+this is the entire active address space of the task. Note that mlock_fixup()
+is used for both mlock()ing and munlock()ing a range of memory. A call to
+mlock() an already VM_LOCKED vma, or to munlock() a vma that is not VM_LOCKED
+is treated as a no-op--mlock_fixup() simply returns.
+
+If the vma passes some filtering described in "Mlocked Pages: Filtering Vmas"
+below, mlock_fixup() will attempt to merge the vma with its neighbors or split
+off a subset of the vma if the range does not cover the entire vma. Once the
+vma has been merged or split or neither, mlock_fixup() will call
+__mlock_vma_pages_range() to fault in the pages via get_user_pages() and
+to mark the pages as mlocked via mlock_vma_page().
+
+Note that the vma being mlocked might be mapped with PROT_NONE. In this case,
+get_user_pages() will be unable to fault in the pages. That's OK. If pages
+do end up getting faulted into this VM_LOCKED vma, we'll handle them in the
+fault path or in vmscan.
+
+Also note that a page returned by get_user_pages() could be truncated or
+migrated out from under us, while we're trying to mlock it. To detect
+this, __mlock_vma_pages_range() tests the page_mapping after acquiring
+the page lock. If the page is still associated with its mapping, we'll
+go ahead and call mlock_vma_page(). If the mapping is gone, we just
+unlock the page and move on. Worse case, this results in page mapped
+in a VM_LOCKED vma remaining on a normal LRU list without being
+PageMlocked(). Again, vmscan will detect and cull such pages.
+
+mlock_vma_page(), called with the page locked [N.B., not "mlocked"] will
+TestSetPageMlocked() for each page returned by get_user_pages(). We use
+TestSetPageMlocked() because the page might already be mlocked by another
+task/vma and we don't want to do extra work. We especially do not want to
+count an mlocked page more than once in the statistics. If the page was
+already mlocked, mlock_vma_page() is done.
+
+If the page was NOT already mlocked, mlock_vma_page() attempts to isolate the
+page from the LRU, as it is likely on the appropriate active or inactive list
+at that time. If the isolate_lru_page() succeeds, mlock_vma_page() will
+putback the page--putback_lru_page()--which will notice that the page is now
+mlocked and divert the page to the zone's unevictable LRU list. If
+mlock_vma_page() is unable to isolate the page from the LRU, vmscan will handle
+it later if/when it attempts to reclaim the page.
+
+
+Mlocked Pages: Filtering Vmas
+
+mlock_fixup() filters several classes of "special" vmas:
+
+1) vmas with VM_IO|VM_PFNMAP set are skipped entirely. The pages behind
+ these mappings are inherently pinned, so we don't need to mark them as
+ mlocked. In any case, most of the pages have no struct page in which to
+ so mark the page. Because of this, get_user_pages() will fail for these
+ vmas, so there is no sense in attempting to visit them.
+
+2) vmas mapping hugetlbfs page are already effectively pinned into memory.
+ We don't need nor want to mlock() these pages. However, to preserve the
+ prior behavior of mlock()--before the unevictable/mlock changes--mlock_fixup()
+ will call make_pages_present() in the hugetlbfs vma range to allocate the
+ huge pages and populate the ptes.
+
+3) vmas with VM_DONTEXPAND|VM_RESERVED are generally user space mappings of
+ kernel pages, such as the vdso page, relay channel pages, etc. These pages
+ are inherently unevictable and are not managed on the LRU lists.
+ mlock_fixup() treats these vmas the same as hugetlbfs vmas. It calls
+ make_pages_present() to populate the ptes.
+
+Note that for all of these special vmas, mlock_fixup() does not set the
+VM_LOCKED flag. Therefore, we won't have to deal with them later during
+munlock() or munmap()--for example, at task exit. Neither does mlock_fixup()
+account these vmas against the task's "locked_vm".
+
+Mlocked Pages: Downgrading the Mmap Semaphore.
+
+mlock_fixup() must be called with the mmap semaphore held for write, because
+it may have to merge or split vmas. However, mlocking a large region of
+memory can take a long time--especially if vmscan must reclaim pages to
+satisfy the regions requirements. Faulting in a large region with the mmap
+semaphore held for write can hold off other faults on the address space, in
+the case of a multi-threaded task. It can also hold off scans of the task's
+address space via /proc. While testing under heavy load, it was observed that
+the ps(1) command could be held off for many minutes while a large segment was
+mlock()ed down.
+
+To address this issue, and to make the system more responsive during mlock()ing
+of large segments, mlock_fixup() downgrades the mmap semaphore to read mode
+during the call to __mlock_vma_pages_range(). This works fine. However, the
+callers of mlock_fixup() expect the semaphore to be returned in write mode.
+So, mlock_fixup() "upgrades" the semphore to write mode. Linux does not
+support an atomic upgrade_sem() call, so mlock_fixup() must drop the semaphore
+and reacquire it in write mode. In a multi-threaded task, it is possible for
+the task memory map to change while the semaphore is dropped. Therefore,
+mlock_fixup() looks up the vma at the range start address after reacquiring
+the semaphore in write mode and verifies that it still covers the original
+range. If not, mlock_fixup() returns an error [-EAGAIN]. All callers of
+mlock_fixup() have been changed to deal with this new error condition.
+
+Note: when munlocking a region, all of the pages should already be resident--
+unless we have racing threads mlocking() and munlocking() regions. So,
+unlocking should not have to wait for page allocations nor faults of any kind.
+Therefore mlock_fixup() does not downgrade the semaphore for munlock().
+
+
+Mlocked Pages: munlock()/munlockall() System Call Handling
+
+The munlock() and munlockall() system calls are handled by the same functions--
+do_mlock[all]()--as the mlock() and mlockall() system calls with the unlock
+vs lock operation indicated by an argument. So, these system calls are also
+handled by mlock_fixup(). Again, if called for an already munlock()ed vma,
+mlock_fixup() simply returns. Because of the vma filtering discussed above,
+VM_LOCKED will not be set in any "special" vmas. So, these vmas will be
+ignored for munlock.
+
+If the vma is VM_LOCKED, mlock_fixup() again attempts to merge or split off
+the specified range. The range is then munlocked via the function
+__munlock_vma_pages_range(). Because the vma access protections could have
+been changed to PROT_NONE after faulting in and mlocking some pages,
+get_user_pages() is unreliable for visiting these pages for munlocking. We
+don't want to leave pages mlocked(), so __munlock_vma_pages_range() uses a
+custom page table walker to find all pages mapped into the specified range.
+Note that this again assumes that all pages in the mlocked() range are resident
+and mapped by the task's page table.
+
+As with __mlock_vma_pages_range(), unlocking can race with truncation and
+migration. It is very important that munlock of a page succeeds, lest we
+leak pages by stranding them in the mlocked state on the unevictable list.
+The munlock page walk pte handler resolves the race with page migration
+by checking the pte for a special swap pte indicating that the page is
+being migrated. If this is the case, the pte handler will wait for the
+migration entry to be replaced and then refetch the pte for the new page.
+Once the pte handler has locked the page, it checks the page_mapping to
+ensure that it still exists. If not, the handler unlocks the page and
+retries the entire process after refetching the pte.
+
+The munlock page walk pte handler unlocks individual pages by calling
+munlock_vma_page(). munlock_vma_page() unconditionally clears the PG_mlocked
+flag using TestClearPageMlocked(). As with mlock_vma_page(), munlock_vma_page()
+use the Test*PageMlocked() function to handle the case where the page might
+have already been unlocked by another task. If the page was mlocked,
+munlock_vma_page() updates that zone statistics for the number of mlocked
+pages. Note, however, that at this point we haven't checked whether the page
+is mapped by other VM_LOCKED vmas.
+
+We can't call try_to_munlock(), the function that walks the reverse map to check
+for other VM_LOCKED vmas, without first isolating the page from the LRU.
+try_to_munlock() is a variant of try_to_unmap() and thus requires that the page
+not be on an lru list. [More on these below.] However, the call to
+isolate_lru_page() could fail, in which case we couldn't try_to_munlock().
+So, we go ahead and clear PG_mlocked up front, as this might be the only chance
+we have. If we can successfully isolate the page, we go ahead and
+try_to_munlock(), which will restore the PG_mlocked flag and update the zone
+page statistics if it finds another vma holding the page mlocked. If we fail
+to isolate the page, we'll have left a potentially mlocked page on the LRU.
+This is fine, because we'll catch it later when/if vmscan tries to reclaim the
+page. This should be relatively rare.
+
+Mlocked Pages: Migrating Them...
+
+A page that is being migrated has been isolated from the lru lists and is
+held locked across unmapping of the page, updating the page's mapping
+[address_space] entry and copying the contents and state, until the
+page table entry has been replaced with an entry that refers to the new
+page. Linux supports migration of mlocked pages and other unevictable
+pages. This involves simply moving the PageMlocked and PageUnevictable states
+from the old page to the new page.
+
+Note that page migration can race with mlocking or munlocking of the same
+page. This has been discussed from the mlock/munlock perspective in the
+respective sections above. Both processes [migration, m[un]locking], hold
+the page locked. This provides the first level of synchronization. Page
+migration zeros out the page_mapping of the old page before unlocking it,
+so m[un]lock can skip these pages. However, as discussed above, munlock
+must wait for a migrating page to be replaced with the new page to prevent
+the new page from remaining mlocked outside of any VM_LOCKED vma.
+
+To ensure that we don't strand pages on the unevictable list because of a
+race between munlock and migration, we must also prevent the munlock pte
+handler from acquiring the old or new page lock from the time that the
+migration subsystem acquires the old page lock, until either migration
+succeeds and the new page is added to the lru or migration fails and
+the old page is putback to the lru. The achieve this coordination,
+the migration subsystem places the new page on success, or the old
+page on failure, back on the lru lists before dropping the respective
+page's lock. It uses the putback_lru_page() function to accomplish this,
+which rechecks the page's overall evictability and adjusts the page
+flags accordingly. To free the old page on success or the new page on
+failure, the migration subsystem just drops what it knows to be the last
+page reference via put_page().
+
+
+Mlocked Pages: mmap(MAP_LOCKED) System Call Handling
+
+In addition the the mlock()/mlockall() system calls, an application can request
+that a region of memory be mlocked using the MAP_LOCKED flag with the mmap()
+call. Furthermore, any mmap() call or brk() call that expands the heap by a
+task that has previously called mlockall() with the MCL_FUTURE flag will result
+in the newly mapped memory being mlocked. Before the unevictable/mlock changes,
+the kernel simply called make_pages_present() to allocate pages and populate
+the page table.
+
+To mlock a range of memory under the unevictable/mlock infrastructure, the
+mmap() handler and task address space expansion functions call
+mlock_vma_pages_range() specifying the vma and the address range to mlock.
+mlock_vma_pages_range() filters vmas like mlock_fixup(), as described above in
+"Mlocked Pages: Filtering Vmas". It will clear the VM_LOCKED flag, which will
+have already been set by the caller, in filtered vmas. Thus these vma's need
+not be visited for munlock when the region is unmapped.
+
+For "normal" vmas, mlock_vma_pages_range() calls __mlock_vma_pages_range() to
+fault/allocate the pages and mlock them. Again, like mlock_fixup(),
+mlock_vma_pages_range() downgrades the mmap semaphore to read mode before
+attempting to fault/allocate and mlock the pages; and "upgrades" the semaphore
+back to write mode before returning.
+
+The callers of mlock_vma_pages_range() will have already added the memory
+range to be mlocked to the task's "locked_vm". To account for filtered vmas,
+mlock_vma_pages_range() returns the number of pages NOT mlocked. All of the
+callers then subtract a non-negative return value from the task's locked_vm.
+A negative return value represent an error--for example, from get_user_pages()
+attempting to fault in a vma with PROT_NONE access. In this case, we leave
+the memory range accounted as locked_vm, as the protections could be changed
+later and pages allocated into that region.
+
+
+Mlocked Pages: munmap()/exit()/exec() System Call Handling
+
+When unmapping an mlocked region of memory, whether by an explicit call to
+munmap() or via an internal unmap from exit() or exec() processing, we must
+munlock the pages if we're removing the last VM_LOCKED vma that maps the pages.
+Before the unevictable/mlock changes, mlocking did not mark the pages in any way,
+so unmapping them required no processing.
+
+To munlock a range of memory under the unevictable/mlock infrastructure, the
+munmap() hander and task address space tear down function call
+munlock_vma_pages_all(). The name reflects the observation that one always
+specifies the entire vma range when munlock()ing during unmap of a region.
+Because of the vma filtering when mlocking() regions, only "normal" vmas that
+actually contain mlocked pages will be passed to munlock_vma_pages_all().
+
+munlock_vma_pages_all() clears the VM_LOCKED vma flag and, like mlock_fixup()
+for the munlock case, calls __munlock_vma_pages_range() to walk the page table
+for the vma's memory range and munlock_vma_page() each resident page mapped by
+the vma. This effectively munlocks the page, only if this is the last
+VM_LOCKED vma that maps the page.
+
+
+Mlocked Page: try_to_unmap()
+
+[Note: the code changes represented by this section are really quite small
+compared to the text to describe what happening and why, and to discuss the
+implications.]
+
+Pages can, of course, be mapped into multiple vmas. Some of these vmas may
+have VM_LOCKED flag set. It is possible for a page mapped into one or more
+VM_LOCKED vmas not to have the PG_mlocked flag set and therefore reside on one
+of the active or inactive LRU lists. This could happen if, for example, a
+task in the process of munlock()ing the page could not isolate the page from
+the LRU. As a result, vmscan/shrink_page_list() might encounter such a page
+as described in "Unevictable Pages and Vmscan [shrink_*_list()]". To
+handle this situation, try_to_unmap() has been enhanced to check for VM_LOCKED
+vmas while it is walking a page's reverse map.
+
+try_to_unmap() is always called, by either vmscan for reclaim or for page
+migration, with the argument page locked and isolated from the LRU. BUG_ON()
+assertions enforce this requirement. Separate functions handle anonymous and
+mapped file pages, as these types of pages have different reverse map
+mechanisms.
+
+ try_to_unmap_anon()
+
+To unmap anonymous pages, each vma in the list anchored in the anon_vma must be
+visited--at least until a VM_LOCKED vma is encountered. If the page is being
+unmapped for migration, VM_LOCKED vmas do not stop the process because mlocked
+pages are migratable. However, for reclaim, if the page is mapped into a
+VM_LOCKED vma, the scan stops. try_to_unmap() attempts to acquire the mmap
+semphore of the mm_struct to which the vma belongs in read mode. If this is
+successful, try_to_unmap() will mlock the page via mlock_vma_page()--we
+wouldn't have gotten to try_to_unmap() if the page were already mlocked--and
+will return SWAP_MLOCK, indicating that the page is unevictable. If the
+mmap semaphore cannot be acquired, we are not sure whether the page is really
+unevictable or not. In this case, try_to_unmap() will return SWAP_AGAIN.
+
+ try_to_unmap_file() -- linear mappings
+
+Unmapping of a mapped file page works the same, except that the scan visits
+all vmas that maps the page's index/page offset in the page's mapping's
+reverse map priority search tree. It must also visit each vma in the page's
+mapping's non-linear list, if the list is non-empty. As for anonymous pages,
+on encountering a VM_LOCKED vma for a mapped file page, try_to_unmap() will
+attempt to acquire the associated mm_struct's mmap semaphore to mlock the page,
+returning SWAP_MLOCK if this is successful, and SWAP_AGAIN, if not.
+
+ try_to_unmap_file() -- non-linear mappings
+
+If a page's mapping contains a non-empty non-linear mapping vma list, then
+try_to_un{map|lock}() must also visit each vma in that list to determine
+whether the page is mapped in a VM_LOCKED vma. Again, the scan must visit
+all vmas in the non-linear list to ensure that the pages is not/should not be
+mlocked. If a VM_LOCKED vma is found in the list, the scan could terminate.
+However, there is no easy way to determine whether the page is actually mapped
+in a given vma--either for unmapping or testing whether the VM_LOCKED vma
+actually pins the page.
+
+So, try_to_unmap_file() handles non-linear mappings by scanning a certain
+number of pages--a "cluster"--in each non-linear vma associated with the page's
+mapping, for each file mapped page that vmscan tries to unmap. If this happens
+to unmap the page we're trying to unmap, try_to_unmap() will notice this on
+return--(page_mapcount(page) == 0)--and return SWAP_SUCCESS. Otherwise, it
+will return SWAP_AGAIN, causing vmscan to recirculate this page. We take
+advantage of the cluster scan in try_to_unmap_cluster() as follows:
+
+For each non-linear vma, try_to_unmap_cluster() attempts to acquire the mmap
+semaphore of the associated mm_struct for read without blocking. If this
+attempt is successful and the vma is VM_LOCKED, try_to_unmap_cluster() will
+retain the mmap semaphore for the scan; otherwise it drops it here. Then,
+for each page in the cluster, if we're holding the mmap semaphore for a locked
+vma, try_to_unmap_cluster() calls mlock_vma_page() to mlock the page. This
+call is a no-op if the page is already locked, but will mlock any pages in
+the non-linear mapping that happen to be unlocked. If one of the pages so
+mlocked is the page passed in to try_to_unmap(), try_to_unmap_cluster() will
+return SWAP_MLOCK, rather than the default SWAP_AGAIN. This will allow vmscan
+to cull the page, rather than recirculating it on the inactive list. Again,
+if try_to_unmap_cluster() cannot acquire the vma's mmap sem, it returns
+SWAP_AGAIN, indicating that the page is mapped by a VM_LOCKED vma, but
+couldn't be mlocked.
+
+
+Mlocked pages: try_to_munlock() Reverse Map Scan
+
+TODO/FIXME: a better name might be page_mlocked()--analogous to the
+page_referenced() reverse map walker--especially if we continue to call this
+from shrink_page_list(). See related TODO/FIXME below.
+
+When munlock_vma_page()--see "Mlocked Pages: munlock()/munlockall() System
+Call Handling" above--tries to munlock a page, or when shrink_page_list()
+encounters an anonymous page that is not yet in the swap cache, they need to
+determine whether or not the page is mapped by any VM_LOCKED vma, without
+actually attempting to unmap all ptes from the page. For this purpose, the
+unevictable/mlock infrastructure introduced a variant of try_to_unmap() called
+try_to_munlock().
+
+try_to_munlock() calls the same functions as try_to_unmap() for anonymous and
+mapped file pages with an additional argument specifing unlock versus unmap
+processing. Again, these functions walk the respective reverse maps looking
+for VM_LOCKED vmas. When such a vma is found for anonymous pages and file
+pages mapped in linear VMAs, as in the try_to_unmap() case, the functions
+attempt to acquire the associated mmap semphore, mlock the page via
+mlock_vma_page() and return SWAP_MLOCK. This effectively undoes the
+pre-clearing of the page's PG_mlocked done by munlock_vma_page() and informs
+shrink_page_list() that the anonymous page should be culled rather than added
+to the swap cache in preparation for a try_to_unmap() that will almost
+certainly fail.
+
+If try_to_unmap() is unable to acquire a VM_LOCKED vma's associated mmap
+semaphore, it will return SWAP_AGAIN. This will allow shrink_page_list()
+to recycle the page on the inactive list and hope that it has better luck
+with the page next time.
+
+For file pages mapped into non-linear vmas, the try_to_munlock() logic works
+slightly differently. On encountering a VM_LOCKED non-linear vma that might
+map the page, try_to_munlock() returns SWAP_AGAIN without actually mlocking
+the page. munlock_vma_page() will just leave the page unlocked and let
+vmscan deal with it--the usual fallback position.
+
+Note that try_to_munlock()'s reverse map walk must visit every vma in a pages'
+reverse map to determine that a page is NOT mapped into any VM_LOCKED vma.
+However, the scan can terminate when it encounters a VM_LOCKED vma and can
+successfully acquire the vma's mmap semphore for read and mlock the page.
+Although try_to_munlock() can be called many [very many!] times when
+munlock()ing a large region or tearing down a large address space that has been
+mlocked via mlockall(), overall this is a fairly rare event. In addition,
+although shrink_page_list() calls try_to_munlock() for every anonymous page that
+it handles that is not yet in the swap cache, on average anonymous pages will
+have very short reverse map lists.
+
+Mlocked Page: Page Reclaim in shrink_*_list()
+
+shrink_active_list() culls any obviously unevictable pages--i.e.,
+!page_evictable(page, NULL)--diverting these to the unevictable lru
+list. However, shrink_active_list() only sees unevictable pages that
+made it onto the active/inactive lru lists. Note that these pages do not
+have PageUnevictable set--otherwise, they would be on the unevictable list and
+shrink_active_list would never see them.
+
+Some examples of these unevictable pages on the LRU lists are:
+
+1) ramfs and ram disk pages that have been placed on the lru lists when
+ first allocated.
+
+2) SHM_LOCKed shared memory pages. shmctl(SHM_LOCK) does not attempt to
+ allocate or fault in the pages in the shared memory region. This happens
+ when an application accesses the page the first time after SHM_LOCKing
+ the segment.
+
+3) Mlocked pages that could not be isolated from the lru and moved to the
+ unevictable list in mlock_vma_page().
+
+3) Pages mapped into multiple VM_LOCKED vmas, but try_to_munlock() couldn't
+ acquire the vma's mmap semaphore to test the flags and set PageMlocked.
+ munlock_vma_page() was forced to let the page back on to the normal
+ LRU list for vmscan to handle.
+
+shrink_inactive_list() also culls any unevictable pages that it finds
+on the inactive lists, again diverting them to the appropriate zone's unevictable
+lru list. shrink_inactive_list() should only see SHM_LOCKed pages that became
+SHM_LOCKed after shrink_active_list() had moved them to the inactive list, or
+pages mapped into VM_LOCKED vmas that munlock_vma_page() couldn't isolate from
+the lru to recheck via try_to_munlock(). shrink_inactive_list() won't notice
+the latter, but will pass on to shrink_page_list().
+
+shrink_page_list() again culls obviously unevictable pages that it could
+encounter for similar reason to shrink_inactive_list(). As already discussed,
+shrink_page_list() proactively looks for anonymous pages that should have
+PG_mlocked set but don't--these would not be detected by page_evictable()--to
+avoid adding them to the swap cache unnecessarily. File pages mapped into
+VM_LOCKED vmas but without PG_mlocked set will make it all the way to
+try_to_unmap(). shrink_page_list() will divert them to the unevictable list when
+try_to_unmap() returns SWAP_MLOCK, as discussed above.
+
+TODO/FIXME: If we can enhance the swap cache to reliably remove entries
+with page_count(page) > 2, as long as all ptes are mapped to the page and
+not the swap entry, we can probably remove the call to try_to_munlock() in
+shrink_page_list() and just remove the page from the swap cache when
+try_to_unmap() returns SWAP_MLOCK. Currently, remove_exclusive_swap_page()
+doesn't seem to allow that.
+
+
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 18:42 ` [PATCH -mm 11/24] pageflag helpers for configed-out flags Rik van Riel
@ 2008-06-11 20:01 ` Andrew Morton
2008-06-11 20:08 ` Rik van Riel
2008-06-11 20:28 ` Lee Schermerhorn
0 siblings, 2 replies; 47+ messages in thread
From: Andrew Morton @ 2008-06-11 20:01 UTC (permalink / raw)
To: Rik van Riel
Cc: linux-kernel, lee.schermerhorn, kosaki.motohiro, Lee.Schermerhorn
On Wed, 11 Jun 2008 14:42:25 -0400
Rik van Riel <riel@redhat.com> wrote:
> Define proper false/noop inline functions for noreclaim page
> flags when !defined(CONFIG_NORECLAIM_LRU)
I changed that to CONFIG_UNEVICTABLE_LRU.
Did we agree that the presence of this config variable is undesirable?
If so, what's involved in making it go away?
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 20:01 ` Andrew Morton
@ 2008-06-11 20:08 ` Rik van Riel
2008-06-11 20:23 ` Lee Schermerhorn
2008-06-11 20:28 ` Lee Schermerhorn
1 sibling, 1 reply; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 20:08 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, lee.schermerhorn, kosaki.motohiro
On Wed, 11 Jun 2008 13:01:45 -0700
Andrew Morton <akpm@linux-foundation.org> wrote:
> On Wed, 11 Jun 2008 14:42:25 -0400
> Rik van Riel <riel@redhat.com> wrote:
>
> > Define proper false/noop inline functions for noreclaim page
> > flags when !defined(CONFIG_NORECLAIM_LRU)
>
> I changed that to CONFIG_UNEVICTABLE_LRU.
>
> Did we agree that the presence of this config variable is undesirable?
> If so, what's involved in making it go away?
We agreed that having CONFIG_NORELAIM_SWAP was bad, that one went away.
As for CONFIG_UNEVICTABLE_LRU, I believe we will want to at least give
embedded people the option to compile without all that code, similar
to CONFIG_SWAP.
--
All rights reversed.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 20:08 ` Rik van Riel
@ 2008-06-11 20:23 ` Lee Schermerhorn
2008-06-11 20:30 ` Rik van Riel
0 siblings, 1 reply; 47+ messages in thread
From: Lee Schermerhorn @ 2008-06-11 20:23 UTC (permalink / raw)
To: Rik van Riel; +Cc: Andrew Morton, linux-kernel, kosaki.motohiro
On Wed, 2008-06-11 at 16:08 -0400, Rik van Riel wrote:
> On Wed, 11 Jun 2008 13:01:45 -0700
> Andrew Morton <akpm@linux-foundation.org> wrote:
> > On Wed, 11 Jun 2008 14:42:25 -0400
> > Rik van Riel <riel@redhat.com> wrote:
> >
> > > Define proper false/noop inline functions for noreclaim page
> > > flags when !defined(CONFIG_NORECLAIM_LRU)
> >
> > I changed that to CONFIG_UNEVICTABLE_LRU.
> >
> > Did we agree that the presence of this config variable is undesirable?
> > If so, what's involved in making it go away?
>
> We agreed that having CONFIG_NORELAIM_SWAP was bad, that one went away.
That was CONFIG_NORELAIM_MLOCK, right?
Which reminds me: we'll need to change the description of
CONFIG_UNEVICTABLE_LRU to state that it uses 2 page flags if, indeed, we
want to say anything about page flag usage in the Kconfig help text.
Not sure that's helpful.
>
> As for CONFIG_UNEVICTABLE_LRU, I believe we will want to at least give
> embedded people the option to compile without all that code, similar
> to CONFIG_SWAP.
Agree.
Lee
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 20:01 ` Andrew Morton
2008-06-11 20:08 ` Rik van Riel
@ 2008-06-11 20:28 ` Lee Schermerhorn
2008-06-11 20:32 ` Rik van Riel
1 sibling, 1 reply; 47+ messages in thread
From: Lee Schermerhorn @ 2008-06-11 20:28 UTC (permalink / raw)
To: Andrew Morton; +Cc: Rik van Riel, linux-kernel, kosaki.motohiro
On Wed, 2008-06-11 at 13:01 -0700, Andrew Morton wrote:
> On Wed, 11 Jun 2008 14:42:25 -0400
> Rik van Riel <riel@redhat.com> wrote:
>
> > Define proper false/noop inline functions for noreclaim page
> > flags when !defined(CONFIG_NORECLAIM_LRU)
>
> I changed that to CONFIG_UNEVICTABLE_LRU.
I noticed that the vmstat items [perhaps these will go away] still use
"noreclaim".
>
> Did we agree that the presence of this config variable is undesirable?
Not sure we did. It does add quite a bit of code that probably wouldn't
be needed/wanted for, say, a laptop system or other small systems that
still have an mmu. I initially made it configurable keeping in mind
your speeches about not burdening smaller systems with larger system
features, ...
> If so, what's involved in making it go away?
Just some busy work. I added a fair number of wrappers and such to
minimize #ifdefs in the .c files. This resulted in quite a few such
#ifdefs in the respective headers. Removing these should mostly
involve removing the #ifdef and the #else case. Most of them that
remain in .c files are for large blocks of code, mostly complete
functions, and can just be removed.
Let me know the consensus. I can send in a patch to remove them if it's
agreed. Might want to wait until we're sure that this is the only
barrier to merging, as the option might be useful during testing.
Lee
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 20:23 ` Lee Schermerhorn
@ 2008-06-11 20:30 ` Rik van Riel
0 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 20:30 UTC (permalink / raw)
To: Lee Schermerhorn; +Cc: Andrew Morton, linux-kernel, kosaki.motohiro
On Wed, 11 Jun 2008 16:23:47 -0400
Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:
> On Wed, 2008-06-11 at 16:08 -0400, Rik van Riel wrote:
> > On Wed, 11 Jun 2008 13:01:45 -0700
> > Andrew Morton <akpm@linux-foundation.org> wrote:
> > > On Wed, 11 Jun 2008 14:42:25 -0400
> > > Rik van Riel <riel@redhat.com> wrote:
> > >
> > > > Define proper false/noop inline functions for noreclaim page
> > > > flags when !defined(CONFIG_NORECLAIM_LRU)
> > >
> > > I changed that to CONFIG_UNEVICTABLE_LRU.
> > >
> > > Did we agree that the presence of this config variable is undesirable?
> > > If so, what's involved in making it go away?
> >
> > We agreed that having CONFIG_NORELAIM_SWAP was bad, that one went away.
>
> That was CONFIG_NORELAIM_MLOCK, right?
You're right.
> Which reminds me: we'll need to change the description of
> CONFIG_UNEVICTABLE_LRU to state that it uses 2 page flags if, indeed, we
> want to say anything about page flag usage in the Kconfig help text.
> Not sure that's helpful.
True, we might as well remove that comment.
--
All rights reversed.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 20:28 ` Lee Schermerhorn
@ 2008-06-11 20:32 ` Rik van Riel
2008-06-11 20:43 ` Lee Schermerhorn
0 siblings, 1 reply; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 20:32 UTC (permalink / raw)
To: Lee Schermerhorn; +Cc: Andrew Morton, linux-kernel, kosaki.motohiro
On Wed, 11 Jun 2008 16:28:03 -0400
Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:
> On Wed, 2008-06-11 at 13:01 -0700, Andrew Morton wrote:
> > On Wed, 11 Jun 2008 14:42:25 -0400
> > Rik van Riel <riel@redhat.com> wrote:
> >
> > > Define proper false/noop inline functions for noreclaim page
> > > flags when !defined(CONFIG_NORECLAIM_LRU)
> >
> > I changed that to CONFIG_UNEVICTABLE_LRU.
>
> I noticed that the vmstat items [perhaps these will go away] still use
> "noreclaim".
$ cat /proc/vmstat
nr_free_pages 3887198
nr_inactive_anon 5043
nr_active_anon 2182
nr_inactive_file 67121
nr_active_file 49045
nr_unevictable 0
nr_mlock 0
Or am I looking at the wrong thing?
--
All rights reversed.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 20:32 ` Rik van Riel
@ 2008-06-11 20:43 ` Lee Schermerhorn
2008-06-11 20:48 ` Rik van Riel
0 siblings, 1 reply; 47+ messages in thread
From: Lee Schermerhorn @ 2008-06-11 20:43 UTC (permalink / raw)
To: Rik van Riel; +Cc: Andrew Morton, linux-kernel, kosaki.motohiro
On Wed, 2008-06-11 at 16:32 -0400, Rik van Riel wrote:
> On Wed, 11 Jun 2008 16:28:03 -0400
> Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:
> > On Wed, 2008-06-11 at 13:01 -0700, Andrew Morton wrote:
> > > On Wed, 11 Jun 2008 14:42:25 -0400
> > > Rik van Riel <riel@redhat.com> wrote:
> > >
> > > > Define proper false/noop inline functions for noreclaim page
> > > > flags when !defined(CONFIG_NORECLAIM_LRU)
> > >
> > > I changed that to CONFIG_UNEVICTABLE_LRU.
> >
> > I noticed that the vmstat items [perhaps these will go away] still use
> > "noreclaim".
>
> $ cat /proc/vmstat
> nr_free_pages 3887198
> nr_inactive_anon 5043
> nr_active_anon 2182
> nr_inactive_file 67121
> nr_active_file 49045
> nr_unevictable 0
> nr_mlock 0
>
> Or am I looking at the wrong thing?
Do you have patch 21/24 applied? In 26-rc5-mm1, I see the
noreclaim_pgs_* vmstat items. They're in the patch 21 you just posted,
as well.
Again, we might decide to drop that patch from the merge. I found the
stats useful during debug and test, but I don't know that they provide
any value in the longer term.
Lee
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 11/24] pageflag helpers for configed-out flags
2008-06-11 20:43 ` Lee Schermerhorn
@ 2008-06-11 20:48 ` Rik van Riel
0 siblings, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-11 20:48 UTC (permalink / raw)
To: Lee Schermerhorn; +Cc: Andrew Morton, linux-kernel, kosaki.motohiro
On Wed, 11 Jun 2008 16:43:01 -0400
Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:
> On Wed, 2008-06-11 at 16:32 -0400, Rik van Riel wrote:
> > On Wed, 11 Jun 2008 16:28:03 -0400
> > Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:
> > > On Wed, 2008-06-11 at 13:01 -0700, Andrew Morton wrote:
> > > > On Wed, 11 Jun 2008 14:42:25 -0400
> > > > Rik van Riel <riel@redhat.com> wrote:
> > > >
> > > > > Define proper false/noop inline functions for noreclaim page
> > > > > flags when !defined(CONFIG_NORECLAIM_LRU)
> > > >
> > > > I changed that to CONFIG_UNEVICTABLE_LRU.
> > >
> > > I noticed that the vmstat items [perhaps these will go away] still use
> > > "noreclaim".
> >
> > $ cat /proc/vmstat
> > nr_free_pages 3887198
> > nr_inactive_anon 5043
> > nr_active_anon 2182
> > nr_inactive_file 67121
> > nr_active_file 49045
> > nr_unevictable 0
> > nr_mlock 0
> >
> > Or am I looking at the wrong thing?
>
> Do you have patch 21/24 applied? In 26-rc5-mm1, I see the
> noreclaim_pgs_* vmstat items. They're in the patch 21 you just posted,
> as well.
Doh!
I am working against:
http://userweb.kernel.org/~akpm/mmotm/
You may want to send Andrew an update against patch 21/24 that
changes those names from noreclaim_pgs_* to unevictable_pgs_*.
> Again, we might decide to drop that patch from the merge. I found the
> stats useful during debug and test, but I don't know that they provide
> any value in the longer term.
That's an option too. I'll let you and Kosaki-san decide on
that, since I had relatively little involvement with the
second half of the patch series recently.
--
All rights reversed.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable
2008-06-11 18:42 ` [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable Rik van Riel
@ 2008-06-12 0:54 ` Nick Piggin
2008-06-12 17:29 ` Rik van Riel
0 siblings, 1 reply; 47+ messages in thread
From: Nick Piggin @ 2008-06-12 0:54 UTC (permalink / raw)
To: Rik van Riel
Cc: linux-kernel, Andrew Morton, Lee Schermerhorn, Kosaki Motohiro,
linux-mm, Eric Whitney
On Thursday 12 June 2008 04:42, Rik van Riel wrote:
> From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
>
> Christoph Lameter pointed out that ram disk pages also clutter the
> LRU lists. When vmscan finds them dirty and tries to clean them,
> the ram disk writeback function just redirties the page so that it
> goes back onto the active list. Round and round she goes...
> Index: linux-2.6.26-rc5-mm2/drivers/block/brd.c
> ===================================================================
> --- linux-2.6.26-rc5-mm2.orig/drivers/block/brd.c 2008-06-10
> 10:46:18.000000000 -0400 +++
> linux-2.6.26-rc5-mm2/drivers/block/brd.c 2008-06-10 16:47:23.000000000
> -0400 @@ -374,8 +374,21 @@ static int brd_ioctl(struct inode *inode
> return error;
> }
>
> +/*
> + * brd_open():
> + * Just mark the mapping as containing unevictable pages
> + */
> +static int brd_open(struct inode *inode, struct file *filp)
> +{
> + struct address_space *mapping = inode->i_mapping;
> +
> + mapping_set_unevictable(mapping);
> + return 0;
> +}
> +
> static struct block_device_operations brd_fops = {
> .owner = THIS_MODULE,
> + .open = brd_open,
> .ioctl = brd_ioctl,
> #ifdef CONFIG_BLK_DEV_XIP
> .direct_access = brd_direct_access,
This isn't the case for brd any longer. It doesn't use the buffer
cache as its backing store, so the buffer cache is reclaimable.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 00/24] VM pageout scalability improvements (V12)
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
` (23 preceding siblings ...)
2008-06-11 18:42 ` [PATCH -mm 24/24] doc: unevictable LRU and mlocked pages documentation Rik van Riel
@ 2008-06-12 5:34 ` Andrew Morton
2008-06-12 13:31 ` Rik van Riel
2008-06-16 5:32 ` KOSAKI Motohiro
24 siblings, 2 replies; 47+ messages in thread
From: Andrew Morton @ 2008-06-12 5:34 UTC (permalink / raw)
To: Rik van Riel; +Cc: linux-kernel, Lee Schermerhorn, Kosaki Motohiro
On Wed, 11 Jun 2008 14:42:14 -0400 Rik van Riel <riel@redhat.com> wrote:
> On large memory systems, the VM can spend way too much time scanning
> through pages that it cannot (or should not) evict from memory. Not
> only does it use up CPU time, but it also provokes lock contention
> and can leave large systems under memory presure in a catatonic state.
Hey, I did some MM testing!
On a 900MB 2-way, allocate and memset 1000MB.
mainline:
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.10s user 10.27s system 62% cpu 16.567 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.12s user 10.23s system 63% cpu 16.234 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.13s user 9.90s system 63% cpu 15.812 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.11s user 9.98s system 65% cpu 15.494 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.12s user 9.94s system 62% cpu 16.000 total
2.6.26-rc5-mm3:
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.15s user 9.81s system 52% cpu 19.117 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.14s user 9.07s system 45% cpu 20.403 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.25s user 9.63s system 34% cpu 28.533 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.15s user 9.35s system 49% cpu 19.196 total
vmm:/home/akpm> time usemem -m 1000
usemem -m 1000 0.13s user 8.79s system 49% cpu 17.993 total
Seems to have saved a little CPU but the IO patterns got worse.
qsbench, 4 processes, memory size tuned to threshold-of-swapping*1.1:
Mainline:
vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
./qsbench -p 4 -m 230 175.45s user 45.67s system 60% cpu 6:08.40 total
2.6.26-rc5-mm3:
vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
./qsbench -p 4 -m 230 178.21s user 28.49s system 99% cpu 3:27.14 total
So woot! Professional qsbench users will be pleased ;) It could have
been a fluke though - iirc qsbench is pretty unstable, especially on
the threshold.
Main thing is: it seems stable. Old LTP ran for an hour or so before I
hit the msgctl08 crash (which is a regression in current mainline).
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 00/24] VM pageout scalability improvements (V12)
2008-06-12 5:34 ` [PATCH -mm 00/24] VM pageout scalability improvements (V12) Andrew Morton
@ 2008-06-12 13:31 ` Rik van Riel
2008-06-16 5:32 ` KOSAKI Motohiro
1 sibling, 0 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-12 13:31 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, Lee Schermerhorn, Kosaki Motohiro
On Wed, 11 Jun 2008 22:34:30 -0700
Andrew Morton <akpm@linux-foundation.org> wrote:
> On a 900MB 2-way, allocate and memset 1000MB.
> Seems to have saved a little CPU but the IO patterns got worse.
In previous tests on my 16GB system, a 16GB fillmem (goes into swap)
saves enough CPU time to make up for potentially worse detection of
the working set (well, not like this program really has a working set).
I'll try this out myself on a smaller system and see if there's
something I can do to make it better.
> qsbench, 4 processes, memory size tuned to threshold-of-swapping*1.1:
>
> Mainline:
>
> vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
> ./qsbench -p 4 -m 230 175.45s user 45.67s system 60% cpu 6:08.40 total
>
> 2.6.26-rc5-mm3:
>
> vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
> ./qsbench -p 4 -m 230 178.21s user 28.49s system 99% cpu 3:27.14 total
>
> So woot! Professional qsbench users will be pleased ;) It could have
> been a fluke though - iirc qsbench is pretty unstable, especially on
> the threshold.
Ignoring references that happen on the active list, only acting
on re-references that happen on the inactive list, gives anonymous
memory something that closer resembles the use-once policy.
Better for some workloads, but potentially worse for others.
Definately worth tweaking the system though, to get performance
as close to where we want it as possible :)
> Main thing is: it seems stable. Old LTP ran for an hour or so before I
> hit the msgctl08 crash (which is a regression in current mainline).
Our main focus has been on stability for the past few months,
trying to get the whole series integrated.
--
All rights reversed.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable
2008-06-12 0:54 ` Nick Piggin
@ 2008-06-12 17:29 ` Rik van Riel
2008-06-12 17:37 ` Nick Piggin
0 siblings, 1 reply; 47+ messages in thread
From: Rik van Riel @ 2008-06-12 17:29 UTC (permalink / raw)
To: Nick Piggin
Cc: linux-kernel, Andrew Morton, Lee Schermerhorn, Kosaki Motohiro,
linux-mm, Eric Whitney
On Thu, 12 Jun 2008 10:54:18 +1000
Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> On Thursday 12 June 2008 04:42, Rik van Riel wrote:
> > From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
> >
> > Christoph Lameter pointed out that ram disk pages also clutter the
> > LRU lists. When vmscan finds them dirty and tries to clean them,
> > the ram disk writeback function just redirties the page so that it
> > goes back onto the active list. Round and round she goes...
> This isn't the case for brd any longer. It doesn't use the buffer
> cache as its backing store, so the buffer cache is reclaimable.
What does that mean?
I know that pages of files that got paged into the page
cache from the ramdisk can be evicted (back to the ram
disk), but how do the brd pages themselves behave?
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable
2008-06-12 17:29 ` Rik van Riel
@ 2008-06-12 17:37 ` Nick Piggin
2008-06-12 17:50 ` Rik van Riel
0 siblings, 1 reply; 47+ messages in thread
From: Nick Piggin @ 2008-06-12 17:37 UTC (permalink / raw)
To: Rik van Riel
Cc: linux-kernel, Andrew Morton, Lee Schermerhorn, Kosaki Motohiro,
linux-mm, Eric Whitney
On Friday 13 June 2008 03:29, Rik van Riel wrote:
> On Thu, 12 Jun 2008 10:54:18 +1000
>
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > On Thursday 12 June 2008 04:42, Rik van Riel wrote:
> > > From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
> > >
> > > Christoph Lameter pointed out that ram disk pages also clutter the
> > > LRU lists. When vmscan finds them dirty and tries to clean them,
> > > the ram disk writeback function just redirties the page so that it
> > > goes back onto the active list. Round and round she goes...
> >
> > This isn't the case for brd any longer. It doesn't use the buffer
> > cache as its backing store, so the buffer cache is reclaimable.
>
> What does that mean?
That your patch is obsolete.
> I know that pages of files that got paged into the page
> cache from the ramdisk can be evicted (back to the ram
> disk), but how do the brd pages themselves behave?
They are not reclaimable. But they have nothing (directly) to do
with brd's i_mapping address space, nor are they put on any LRU
lists.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable
2008-06-12 17:37 ` Nick Piggin
@ 2008-06-12 17:50 ` Rik van Riel
2008-06-12 17:57 ` Nick Piggin
0 siblings, 1 reply; 47+ messages in thread
From: Rik van Riel @ 2008-06-12 17:50 UTC (permalink / raw)
To: Nick Piggin
Cc: linux-kernel, Andrew Morton, Lee Schermerhorn, Kosaki Motohiro,
linux-mm, Eric Whitney
On Fri, 13 Jun 2008 03:37:56 +1000
Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > > This isn't the case for brd any longer. It doesn't use the buffer
> > > cache as its backing store, so the buffer cache is reclaimable.
> > I know that pages of files that got paged into the page
> > cache from the ramdisk can be evicted (back to the ram
> > disk), but how do the brd pages themselves behave?
>
> They are not reclaimable. But they have nothing (directly) to do
> with brd's i_mapping address space, nor are they put on any LRU
> lists.
Ahhhh, doh!
I'm mailing Andrew a patch right now that undoes the
brd.c part of patch 14/24. The ramdisk part is correct
and should stay (afaict).
--
All Rights Reversed
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable
2008-06-12 17:50 ` Rik van Riel
@ 2008-06-12 17:57 ` Nick Piggin
0 siblings, 0 replies; 47+ messages in thread
From: Nick Piggin @ 2008-06-12 17:57 UTC (permalink / raw)
To: Rik van Riel
Cc: linux-kernel, Andrew Morton, Lee Schermerhorn, Kosaki Motohiro,
linux-mm, Eric Whitney
On Friday 13 June 2008 03:50, Rik van Riel wrote:
> On Fri, 13 Jun 2008 03:37:56 +1000
>
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > > > This isn't the case for brd any longer. It doesn't use the buffer
> > > > cache as its backing store, so the buffer cache is reclaimable.
> > >
> > > I know that pages of files that got paged into the page
> > > cache from the ramdisk can be evicted (back to the ram
> > > disk), but how do the brd pages themselves behave?
> >
> > They are not reclaimable. But they have nothing (directly) to do
> > with brd's i_mapping address space, nor are they put on any LRU
> > lists.
>
> Ahhhh, doh!
>
> I'm mailing Andrew a patch right now that undoes the
> brd.c part of patch 14/24. The ramdisk part is correct
> and should stay (afaict).
The ramfs part? Yes, that looks correct to me.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 06/24] vmscan: split LRU lists into anon & file sets
2008-06-11 18:42 ` [PATCH -mm 06/24] vmscan: split LRU lists into anon & file sets Rik van Riel
@ 2008-06-13 0:39 ` Hiroshi Shimamoto
2008-06-13 17:48 ` [PATCH] fix printk in show_free_areas Rik van Riel
0 siblings, 1 reply; 47+ messages in thread
From: Hiroshi Shimamoto @ 2008-06-13 0:39 UTC (permalink / raw)
To: Rik van Riel
Cc: linux-kernel, Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
Rik van Riel wrote:
> From: Rik van Riel <riel@redhat.com>
>
> Split the LRU lists in two, one set for pages that are backed by
> real file systems ("file") and one for pages that are backed by
> memory and swap ("anon"). The latter includes tmpfs.
>
> The advantage of doing this is that the VM will not have to scan
> over lots of anonymous pages (which we generally do not want to
> swap out), just to find the page cache pages that it should evict.
>
> This patch has the infrastructure and a basic policy to balance
> how much we scan the anon lists and how much we scan the file
> lists. The big policy changes are in separate patches.
>
> Signed-off-by: Rik van Riel <riel@redhat.com>
> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Hi,
nitpick
...
> Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-10 13:34:48.000000000 -0400
> +++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-10 13:35:23.000000000 -0400
> @@ -1834,10 +1834,13 @@ void show_free_areas(void)
> }
> }
>
> - printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu\n"
> + printk("Active_anon:%lu active_file:%lu inactive_anon%lu\n"
inactive_anon:%lu?
thanks,
Hiroshi Shimamoto
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH] fix printk in show_free_areas
2008-06-13 0:39 ` Hiroshi Shimamoto
@ 2008-06-13 17:48 ` Rik van Riel
2008-06-13 20:21 ` [PATCH] collect lru meminfo statistics from correct offset Lee Schermerhorn
2008-06-15 15:07 ` [PATCH] fix printk in show_free_areas KOSAKI Motohiro
0 siblings, 2 replies; 47+ messages in thread
From: Rik van Riel @ 2008-06-13 17:48 UTC (permalink / raw)
To: Hiroshi Shimamoto
Cc: linux-kernel, Andrew Morton, Lee Schermerhorn, Kosaki Motohiro
OFix typo in show_free_areas.
Debugged-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.26-rc5-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/mm/page_alloc.c 2008-06-12 13:48:54.000000000 -0400
+++ linux-2.6.26-rc5-mm2/mm/page_alloc.c 2008-06-13 13:46:43.000000000 -0400
@@ -1929,7 +1929,7 @@ void show_free_areas(void)
}
}
- printk("Active_anon:%lu active_file:%lu inactive_anon%lu\n"
+ printk("Active_anon:%lu active_file:%lu inactive_anon:%lu\n"
" inactive_file:%lu"
//TODO: check/adjust line lengths
#ifdef CONFIG_UNEVICTABLE_LRU
^ permalink raw reply [flat|nested] 47+ messages in thread
* [PATCH] collect lru meminfo statistics from correct offset
2008-06-13 17:48 ` [PATCH] fix printk in show_free_areas Rik van Riel
@ 2008-06-13 20:21 ` Lee Schermerhorn
2008-06-15 15:07 ` [PATCH] fix printk in show_free_areas KOSAKI Motohiro
1 sibling, 0 replies; 47+ messages in thread
From: Lee Schermerhorn @ 2008-06-13 20:21 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, Rik van Riel, linux-mm
PATCH collect lru meminfo statistics from correct offset
Against: 2.6.26-rc5-mm3
Incremental fix to: vmscan-split-lru-lists-into-anon-file-sets.patch
Offset 'lru' by 'NR_LRU_BASE' to obtain global page state for
lru list 'lru'.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
fs/proc/proc_misc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.26-rc5-mm3/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.26-rc5-mm3.orig/fs/proc/proc_misc.c 2008-06-13 15:16:17.000000000 -0400
+++ linux-2.6.26-rc5-mm3/fs/proc/proc_misc.c 2008-06-13 15:44:24.000000000 -0400
@@ -158,7 +158,7 @@ static int meminfo_read_proc(char *page,
get_vmalloc_info(&vmi);
for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
- pages[lru] = global_page_state(lru);
+ pages[lru] = global_page_state(NR_LRU_BASE + lru);
/*
* Tagged format, for easy grepping and expansion.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH] fix printk in show_free_areas
2008-06-13 17:48 ` [PATCH] fix printk in show_free_areas Rik van Riel
2008-06-13 20:21 ` [PATCH] collect lru meminfo statistics from correct offset Lee Schermerhorn
@ 2008-06-15 15:07 ` KOSAKI Motohiro
1 sibling, 0 replies; 47+ messages in thread
From: KOSAKI Motohiro @ 2008-06-15 15:07 UTC (permalink / raw)
To: Rik van Riel
Cc: Hiroshi Shimamoto, linux-kernel, Andrew Morton, Lee Schermerhorn
> - printk("Active_anon:%lu active_file:%lu inactive_anon%lu\n"
> + printk("Active_anon:%lu active_file:%lu inactive_anon:%lu\n"
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 00/24] VM pageout scalability improvements (V12)
2008-06-12 5:34 ` [PATCH -mm 00/24] VM pageout scalability improvements (V12) Andrew Morton
2008-06-12 13:31 ` Rik van Riel
@ 2008-06-16 5:32 ` KOSAKI Motohiro
2008-06-16 6:20 ` Andrew Morton
1 sibling, 1 reply; 47+ messages in thread
From: KOSAKI Motohiro @ 2008-06-16 5:32 UTC (permalink / raw)
To: Andrew Morton
Cc: kosaki.motohiro, Rik van Riel, linux-kernel, Lee Schermerhorn
Hi
> qsbench, 4 processes, memory size tuned to threshold-of-swapping*1.1:
>
> Mainline:
>
> vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
> ./qsbench -p 4 -m 230 175.45s user 45.67s system 60% cpu 6:08.40 total
>
> 2.6.26-rc5-mm3:
>
> vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
> ./qsbench -p 4 -m 230 178.21s user 28.49s system 99% cpu 3:27.14 total
Where can I get this benchmark?
I found following URL. but it doesn't have -m option.
I guess it is too old ;)
http://lkml.org/lkml/2001/10/9/90
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 00/24] VM pageout scalability improvements (V12)
2008-06-16 5:32 ` KOSAKI Motohiro
@ 2008-06-16 6:20 ` Andrew Morton
2008-06-16 6:22 ` KOSAKI Motohiro
0 siblings, 1 reply; 47+ messages in thread
From: Andrew Morton @ 2008-06-16 6:20 UTC (permalink / raw)
To: KOSAKI Motohiro; +Cc: Rik van Riel, linux-kernel, Lee Schermerhorn
On Mon, 16 Jun 2008 14:32:33 +0900 KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> Hi
>
> > qsbench, 4 processes, memory size tuned to threshold-of-swapping*1.1:
> >
> > Mainline:
> >
> > vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
> > ./qsbench -p 4 -m 230 175.45s user 45.67s system 60% cpu 6:08.40 total
> >
> > 2.6.26-rc5-mm3:
> >
> > vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
> > ./qsbench -p 4 -m 230 178.21s user 28.49s system 99% cpu 3:27.14 total
>
> Where can I get this benchmark?
>
http://userweb.kernel.org/~akpm/qsbench.tar.gz
> I guess it is too old ;)
I might have added it - I forget.
^ permalink raw reply [flat|nested] 47+ messages in thread
* Re: [PATCH -mm 00/24] VM pageout scalability improvements (V12)
2008-06-16 6:20 ` Andrew Morton
@ 2008-06-16 6:22 ` KOSAKI Motohiro
0 siblings, 0 replies; 47+ messages in thread
From: KOSAKI Motohiro @ 2008-06-16 6:22 UTC (permalink / raw)
To: Andrew Morton
Cc: kosaki.motohiro, Rik van Riel, linux-kernel, Lee Schermerhorn
> > > vmm:/home/akpm/qsbench> time ./qsbench -p 4 -m 230
> > > ./qsbench -p 4 -m 230 178.21s user 28.49s system 99% cpu 3:27.14 total
> >
> > Where can I get this benchmark?
>
> http://userweb.kernel.org/~akpm/qsbench.tar.gz
>
> > I guess it is too old ;)
>
> I might have added it - I forget.
Thanks.
I'll test this benchmark :)
^ permalink raw reply [flat|nested] 47+ messages in thread
end of thread, other threads:[~2008-06-16 6:22 UTC | newest]
Thread overview: 47+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-06-11 18:42 [PATCH -mm 00/24] VM pageout scalability improvements (V12) Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 01/24] vmscan: move isolate_lru_page() to vmscan.c Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 02/24] vmscan: Use an indexed array for LRU variables Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 03/24] swap: use an array for the LRU pagevecs Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 04/24] vmscan: free swap space on swap-in/activation Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 05/24] define page_file_cache() function Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 06/24] vmscan: split LRU lists into anon & file sets Rik van Riel
2008-06-13 0:39 ` Hiroshi Shimamoto
2008-06-13 17:48 ` [PATCH] fix printk in show_free_areas Rik van Riel
2008-06-13 20:21 ` [PATCH] collect lru meminfo statistics from correct offset Lee Schermerhorn
2008-06-15 15:07 ` [PATCH] fix printk in show_free_areas KOSAKI Motohiro
2008-06-11 18:42 ` [PATCH -mm 07/24] vmscan: second chance replacement for anonymous pages Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 08/24] vmscan: fix pagecache reclaim referenced bit check Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 09/24] vmscan: add newly swapped in pages to the inactive list Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 10/24] more aggressively use lumpy reclaim Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 11/24] pageflag helpers for configed-out flags Rik van Riel
2008-06-11 20:01 ` Andrew Morton
2008-06-11 20:08 ` Rik van Riel
2008-06-11 20:23 ` Lee Schermerhorn
2008-06-11 20:30 ` Rik van Riel
2008-06-11 20:28 ` Lee Schermerhorn
2008-06-11 20:32 ` Rik van Riel
2008-06-11 20:43 ` Lee Schermerhorn
2008-06-11 20:48 ` Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 12/24] Unevictable LRU Infrastructure Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 13/24] Unevictable LRU Page Statistics Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 14/24] Ramfs and Ram Disk pages are unevictable Rik van Riel
2008-06-12 0:54 ` Nick Piggin
2008-06-12 17:29 ` Rik van Riel
2008-06-12 17:37 ` Nick Piggin
2008-06-12 17:50 ` Rik van Riel
2008-06-12 17:57 ` Nick Piggin
2008-06-11 18:42 ` [PATCH -mm 15/24] SHM_LOCKED " Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 16/24] mlock: mlocked " Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 17/24] mlock: downgrade mmap sem while populating mlocked regions Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 18/24] mmap: handle mlocked pages during map, remap, unmap Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 19/24] vmstat: mlocked pages statistics Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 20/24] swap: cull unevictable pages in fault path Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 21/24] vmstat: unevictable and mlocked pages vm events Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 22/24] vmscan: unevictable LRU scan sysctl Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 23/24] mlock: count attempts to free mlocked page Rik van Riel
2008-06-11 18:42 ` [PATCH -mm 24/24] doc: unevictable LRU and mlocked pages documentation Rik van Riel
2008-06-12 5:34 ` [PATCH -mm 00/24] VM pageout scalability improvements (V12) Andrew Morton
2008-06-12 13:31 ` Rik van Riel
2008-06-16 5:32 ` KOSAKI Motohiro
2008-06-16 6:20 ` Andrew Morton
2008-06-16 6:22 ` KOSAKI Motohiro
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).