* [S+Q Core 0/6] SLUB: Queueing Core
@ 2010-08-20 19:01 Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 1/6] slub: Add per cpu queueing Christoph Lameter
` (5 more replies)
0 siblings, 6 replies; 8+ messages in thread
From: Christoph Lameter @ 2010-08-20 19:01 UTC (permalink / raw)
To: Pekka Enberg; +Cc: linux-mm, David Rientjes
This is the core of the queueing for SLUB. More advanced stuff like
shared/alien caches and expiration is not included.
Patches require the S+Q Cleanup V4 to be applied first.
1. Core (per cpu queues)
Basic queues that are statically sized and only work as a per cpu queue
2. Resizable queues
Allow dynamic resizing of the per cpu queues
3-5 some cleanups made possible by the above patches
6. Basic NUMA support
This only implements the basic object based policy support for
NUMA without additional optimizations.
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [S+Q Core 1/6] slub: Add per cpu queueing
2010-08-20 19:01 [S+Q Core 0/6] SLUB: Queueing Core Christoph Lameter
@ 2010-08-20 19:01 ` Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 2/6] slub: Allow resizing of per cpu queues Christoph Lameter
` (4 subsequent siblings)
5 siblings, 0 replies; 8+ messages in thread
From: Christoph Lameter @ 2010-08-20 19:01 UTC (permalink / raw)
To: Pekka Enberg; +Cc: linux-mm, David Rientjes
[-- Attachment #1: unified_core --]
[-- Type: text/plain, Size: 53025 bytes --]
This patch adds SLAB style cpu queueing and uses a new way for
managing objects in the slabs using bitmaps. It uses a percpu queue so that
free operations can be properly buffered and a bitmap for managing the
free/allocated state in the slabs. The approach uses slightly more memory
(due to the need to place large bitmaps --sized a few words--in some
slab pages) but in general does compete well in terms of space use.
The storage format using bitmaps avoids the SLAB management structure that
SLAB needs for each slab page and therefore metadata is more compact
and easily fits into a cacheline.
The SLAB scheme of not touching the object during management is adopted.
SLUB can now efficiently free and allocate cache cold objects.
The queueing scheme addresses also the issue that the free slowpath
was taken too frequently.
This patch only implements staticallly sized per cpu queues and does
not deal with NUMA queueing and shared queuing. Frees to remote nodes
are simply directly freed to the slab taking the per page slab lock.
(A later patch introduces the infamous alien caches to SLUB.)
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
include/linux/page-flags.h | 5
include/linux/slub_def.h | 48 +-
init/Kconfig | 14
mm/slub.c | 1067 +++++++++++++++++++++------------------------
4 files changed, 537 insertions(+), 597 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2010-08-19 20:10:20.000000000 -0500
+++ linux-2.6/mm/slub.c 2010-08-19 20:11:07.000000000 -0500
@@ -1,11 +1,11 @@
/*
- * SLUB: A slab allocator that limits cache line use instead of queuing
- * objects in per cpu and per node lists.
+ * SLUB: The unified slab allocator.
*
* The allocator synchronizes using per slab locks and only
* uses a centralized lock to manage a pool of partial slabs.
*
* (C) 2007 SGI, Christoph Lameter
+ * (C) 2010 Linux Foundation, Christoph Lameter
*/
#include <linux/mm.h>
@@ -83,27 +83,6 @@
* minimal so we rely on the page allocators per cpu caches for
* fast frees and allocs.
*
- * Overloading of page flags that are otherwise used for LRU management.
- *
- * PageActive The slab is frozen and exempt from list processing.
- * This means that the slab is dedicated to a purpose
- * such as satisfying allocations for a specific
- * processor. Objects may be freed in the slab while
- * it is frozen but slab_free will then skip the usual
- * list operations. It is up to the processor holding
- * the slab to integrate the slab into the slab lists
- * when the slab is no longer needed.
- *
- * One use of this flag is to mark slabs that are
- * used for allocations. Then such a slab becomes a cpu
- * slab. The cpu slab may be equipped with an additional
- * freelist that allows lockless access to
- * free objects in addition to the regular freelist
- * that requires the slab lock.
- *
- * PageError Slab requires special handling due to debug
- * options set. This moves slab handling out of
- * the fast path and disables lockless freelists.
*/
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
@@ -257,38 +236,95 @@ static inline int check_valid_pointer(st
return 1;
}
-static inline void *get_freepointer(struct kmem_cache *s, void *object)
-{
- return *(void **)(object + s->offset);
-}
-
-static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
-{
- *(void **)(object + s->offset) = fp;
-}
-
/* Loop over all objects in a slab */
#define for_each_object(__p, __s, __addr, __objects) \
for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
__p += (__s)->size)
-/* Scan freelist */
-#define for_each_free_object(__p, __s, __free) \
- for (__p = (__free); __p; __p = get_freepointer((__s), __p))
-
/* Determine object index from a given position */
static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
{
return (p - addr) / s->size;
}
+static inline int map_in_page_struct(struct page *page)
+{
+ return page->objects <= BITS_PER_LONG;
+}
+
+static inline unsigned long *map(struct page *page)
+{
+ if (map_in_page_struct(page))
+ return (unsigned long *)&page->freelist;
+ else
+ return page->freelist;
+}
+
+static inline int map_size(struct page *page)
+{
+ return BITS_TO_LONGS(page->objects) * sizeof(unsigned long);
+}
+
+static inline int available(struct page *page)
+{
+ return bitmap_weight(map(page), page->objects);
+}
+
+static inline int all_objects_available(struct page *page)
+{
+ return bitmap_full(map(page), page->objects);
+}
+
+static inline int all_objects_used(struct page *page)
+{
+ return bitmap_empty(map(page), page->objects);
+}
+
+static inline int inuse(struct page *page)
+{
+ return page->objects - available(page);
+}
+
+/*
+ * Basic queue functions
+ */
+
+static inline void *queue_get(struct kmem_cache_queue *q)
+{
+ return q->object[--q->objects];
+}
+
+static inline void queue_put(struct kmem_cache_queue *q, void *object)
+{
+ q->object[q->objects++] = object;
+}
+
+static inline int queue_full(struct kmem_cache_queue *q)
+{
+ return q->objects == QUEUE_SIZE;
+}
+
+static inline int queue_empty(struct kmem_cache_queue *q)
+{
+ return q->objects == 0;
+}
+
static inline struct kmem_cache_order_objects oo_make(int order,
unsigned long size)
{
- struct kmem_cache_order_objects x = {
- (order << OO_SHIFT) + (PAGE_SIZE << order) / size
- };
+ struct kmem_cache_order_objects x;
+ unsigned long objects;
+ unsigned long page_size = PAGE_SIZE << order;
+ unsigned long ws = sizeof(unsigned long);
+
+ objects = page_size / size;
+
+ if (objects > BITS_PER_LONG)
+ /* Bitmap must fit into the slab as well */
+ objects = ((page_size / ws) * BITS_PER_LONG) /
+ ((size / ws) * BITS_PER_LONG + 1);
+ x.x = (order << OO_SHIFT) + objects;
return x;
}
@@ -355,10 +391,7 @@ static struct track *get_track(struct km
{
struct track *p;
- if (s->offset)
- p = object + s->offset + sizeof(void *);
- else
- p = object + s->inuse;
+ p = object + s->inuse;
return p + alloc;
}
@@ -406,8 +439,8 @@ static void print_tracking(struct kmem_c
static void print_page_info(struct page *page)
{
- printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
- page, page->objects, page->inuse, page->freelist, page->flags);
+ printk(KERN_ERR "INFO: Slab 0x%p objects=%u new=%u fp=0x%p flags=0x%04lx\n",
+ page, page->objects, available(page), page->freelist, page->flags);
}
@@ -446,8 +479,8 @@ static void print_trailer(struct kmem_ca
print_page_info(page);
- printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
- p, p - addr, get_freepointer(s, p));
+ printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n\n",
+ p, p - addr);
if (p > addr + 16)
print_section("Bytes b4", p - 16, 16);
@@ -458,10 +491,7 @@ static void print_trailer(struct kmem_ca
print_section("Redzone", p + s->objsize,
s->inuse - s->objsize);
- if (s->offset)
- off = s->offset + sizeof(void *);
- else
- off = s->inuse;
+ off = s->inuse;
if (s->flags & SLAB_STORE_USER)
off += 2 * sizeof(struct track);
@@ -555,8 +585,6 @@ static int check_bytes_and_report(struct
*
* object address
* Bytes of the object to be managed.
- * If the freepointer may overlay the object then the free
- * pointer is the first word of the object.
*
* Poisoning uses 0x6b (POISON_FREE) and the last byte is
* 0xa5 (POISON_END)
@@ -572,9 +600,8 @@ static int check_bytes_and_report(struct
* object + s->inuse
* Meta data starts here.
*
- * A. Free pointer (if we cannot overwrite object on free)
- * B. Tracking data for SLAB_STORE_USER
- * C. Padding to reach required alignment boundary or at mininum
+ * A. Tracking data for SLAB_STORE_USER
+ * B. Padding to reach required alignment boundary or at mininum
* one word if debugging is on to be able to detect writes
* before the word boundary.
*
@@ -592,10 +619,6 @@ static int check_pad_bytes(struct kmem_c
{
unsigned long off = s->inuse; /* The end of info */
- if (s->offset)
- /* Freepointer is placed after the object. */
- off += sizeof(void *);
-
if (s->flags & SLAB_STORE_USER)
/* We also have user information there */
off += 2 * sizeof(struct track);
@@ -620,15 +643,42 @@ static int slab_pad_check(struct kmem_ca
return 1;
start = page_address(page);
- length = (PAGE_SIZE << compound_order(page));
- end = start + length;
- remainder = length % s->size;
+ end = start + (PAGE_SIZE << compound_order(page));
+
+ /* Check for special case of bitmap at the end of the page */
+ if (!map_in_page_struct(page)) {
+ if ((u8 *)page->freelist > start && (u8 *)page->freelist < end)
+ end = page->freelist;
+ else
+ slab_err(s, page, "pagemap pointer invalid =%p start=%p end=%p objects=%d",
+ page->freelist, start, end, page->objects);
+ }
+
+ length = end - start;
+ remainder = length - page->objects * s->size;
if (!remainder)
return 1;
fault = check_bytes(end - remainder, POISON_INUSE, remainder);
- if (!fault)
- return 1;
+ if (!fault) {
+ u8 *freelist_end;
+
+ if (map_in_page_struct(page))
+ return 1;
+
+ end = start + (PAGE_SIZE << compound_order(page));
+ freelist_end = page->freelist + map_size(page);
+ remainder = end - freelist_end;
+
+ if (!remainder)
+ return 1;
+
+ fault = check_bytes(freelist_end, POISON_INUSE,
+ remainder);
+ if (!fault)
+ return 1;
+ }
+
while (end > fault && end[-1] == POISON_INUSE)
end--;
@@ -671,25 +721,6 @@ static int check_object(struct kmem_cach
*/
check_pad_bytes(s, page, p);
}
-
- if (!s->offset && active)
- /*
- * Object and freepointer overlap. Cannot check
- * freepointer while object is allocated.
- */
- return 1;
-
- /* Check free pointer validity */
- if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
- object_err(s, page, p, "Freepointer corrupt");
- /*
- * No choice but to zap it and thus lose the remainder
- * of the free objects in this slab. May cause
- * another error because the object count is now wrong.
- */
- set_freepointer(s, p, NULL);
- return 0;
- }
return 1;
}
@@ -710,51 +741,45 @@ static int check_slab(struct kmem_cache
s->name, page->objects, maxobj);
return 0;
}
- if (page->inuse > page->objects) {
- slab_err(s, page, "inuse %u > max %u",
- s->name, page->inuse, page->objects);
- return 0;
- }
+
/* Slab_pad_check fixes things up after itself */
slab_pad_check(s, page);
return 1;
}
/*
- * Determine if a certain object on a page is on the freelist. Must hold the
- * slab lock to guarantee that the chains are in a consistent state.
+ * Determine if a certain object on a page is on the free map.
*/
-static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
+static int object_marked_free(struct kmem_cache *s, struct page *page, void *search)
+{
+ return test_bit(slab_index(search, s, page_address(page)), map(page));
+}
+
+/* Verify the integrity of the metadata in a slab page */
+static int verify_slab(struct kmem_cache *s, struct page *page)
{
int nr = 0;
- void *fp = page->freelist;
- void *object = NULL;
unsigned long max_objects;
+ void *start = page_address(page);
+ unsigned long size = PAGE_SIZE << compound_order(page);
- while (fp && nr <= page->objects) {
- if (fp == search)
- return 1;
- if (!check_valid_pointer(s, page, fp)) {
- if (object) {
- object_err(s, page, object,
- "Freechain corrupt");
- set_freepointer(s, object, NULL);
- break;
- } else {
- slab_err(s, page, "Freepointer corrupt");
- page->freelist = NULL;
- page->inuse = page->objects;
- slab_fix(s, "Freelist cleared");
- return 0;
- }
- break;
- }
- object = fp;
- fp = get_freepointer(s, object);
- nr++;
+ nr = available(page);
+
+ if (map_in_page_struct(page))
+ max_objects = size / s->size;
+ else {
+ if (page->freelist <= start || page->freelist >= start + size) {
+ slab_err(s, page, "Invalid pointer to bitmap of free objects max_objects=%d!",
+ page->objects);
+ /* Switch to bitmap in page struct */
+ page->objects = max_objects = BITS_PER_LONG;
+ page->freelist = 0L;
+ slab_fix(s, "Slab sized for %d objects. ALl objects marked in use.",
+ BITS_PER_LONG);
+ } else
+ max_objects = ((void *)page->freelist - start) / s->size;
}
- max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
if (max_objects > MAX_OBJS_PER_PAGE)
max_objects = MAX_OBJS_PER_PAGE;
@@ -763,24 +788,19 @@ static int on_freelist(struct kmem_cache
"should be %d", page->objects, max_objects);
page->objects = max_objects;
slab_fix(s, "Number of objects adjusted.");
+ return 0;
}
- if (page->inuse != page->objects - nr) {
- slab_err(s, page, "Wrong object count. Counter is %d but "
- "counted were %d", page->inuse, page->objects - nr);
- page->inuse = page->objects - nr;
- slab_fix(s, "Object count adjusted.");
- }
- return search == NULL;
+ return 1;
}
static void trace(struct kmem_cache *s, struct page *page, void *object,
int alloc)
{
if (s->flags & SLAB_TRACE) {
- printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
+ printk(KERN_INFO "TRACE %s %s 0x%p free=%d fp=0x%p\n",
s->name,
alloc ? "alloc" : "free",
- object, page->inuse,
+ object, available(page),
page->freelist);
if (!alloc)
@@ -826,22 +846,24 @@ static inline void slab_free_hook_irq(st
/*
* Tracking of fully allocated slabs for debugging purposes.
*/
-static void add_full(struct kmem_cache_node *n, struct page *page)
+static inline void add_full(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct page *page)
{
+
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
spin_lock(&n->list_lock);
list_add(&page->lru, &n->full);
spin_unlock(&n->list_lock);
}
-static void remove_full(struct kmem_cache *s, struct page *page)
+static inline void remove_full(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct page *page)
{
- struct kmem_cache_node *n;
-
if (!(s->flags & SLAB_STORE_USER))
return;
- n = get_node(s, page_to_nid(page));
-
spin_lock(&n->list_lock);
list_del(&page->lru);
spin_unlock(&n->list_lock);
@@ -894,25 +916,30 @@ static void setup_object_debug(struct km
init_tracking(s, object);
}
-static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
- void *object, unsigned long addr)
+static noinline int alloc_debug_processing(struct kmem_cache *s,
+ void *object, unsigned long addr)
{
+ struct page *page = virt_to_head_page(object);
+
if (!check_slab(s, page))
goto bad;
- if (!on_freelist(s, page, object)) {
- object_err(s, page, object, "Object already allocated");
+ if (!check_valid_pointer(s, page, object)) {
+ object_err(s, page, object, "Pointer check fails");
goto bad;
}
- if (!check_valid_pointer(s, page, object)) {
- object_err(s, page, object, "Freelist Pointer check fails");
+ if (object_marked_free(s, page, object)) {
+ object_err(s, page, object, "Allocated object still marked free in slab");
goto bad;
}
if (!check_object(s, page, object, 0))
goto bad;
+ if (!verify_slab(s, page))
+ goto bad;
+
/* Success perform special debug activities for allocs */
if (s->flags & SLAB_STORE_USER)
set_track(s, object, TRACK_ALLOC, addr);
@@ -928,8 +955,7 @@ bad:
* as used avoids touching the remaining objects.
*/
slab_fix(s, "Marking all objects used");
- page->inuse = page->objects;
- page->freelist = NULL;
+ bitmap_zero(map(page), page->objects);
}
return 0;
}
@@ -945,7 +971,7 @@ static noinline int free_debug_processin
goto fail;
}
- if (on_freelist(s, page, object)) {
+ if (object_marked_free(s, page, object)) {
object_err(s, page, object, "Object already free");
goto fail;
}
@@ -968,13 +994,11 @@ static noinline int free_debug_processin
goto fail;
}
- /* Special debug activities for freeing objects */
- if (!PageSlubFrozen(page) && !page->freelist)
- remove_full(s, page);
if (s->flags & SLAB_STORE_USER)
set_track(s, object, TRACK_FREE, addr);
trace(s, page, object, 0);
init_object(s, object, 0);
+ verify_slab(s, page);
return 1;
fail:
@@ -1079,7 +1103,8 @@ static inline int slab_pad_check(struct
{ return 1; }
static inline int check_object(struct kmem_cache *s, struct page *page,
void *object, int active) { return 1; }
-static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
+static inline void add_full(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct page *page) {}
static inline unsigned long kmem_cache_flags(unsigned long objsize,
unsigned long flags, const char *name,
void (*ctor)(void *))
@@ -1181,8 +1206,8 @@ static struct page *new_slab(struct kmem
{
struct page *page;
void *start;
- void *last;
void *p;
+ unsigned long size;
BUG_ON(flags & GFP_SLAB_BUG_MASK);
@@ -1194,23 +1219,20 @@ static struct page *new_slab(struct kmem
inc_slabs_node(s, page_to_nid(page), page->objects);
page->slab = s;
page->flags |= 1 << PG_slab;
-
start = page_address(page);
+ size = PAGE_SIZE << compound_order(page);
if (unlikely(s->flags & SLAB_POISON))
- memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
+ memset(start, POISON_INUSE, size);
- last = start;
- for_each_object(p, s, start, page->objects) {
- setup_object(s, page, last);
- set_freepointer(s, last, p);
- last = p;
- }
- setup_object(s, page, last);
- set_freepointer(s, last, NULL);
+ if (!map_in_page_struct(page))
+ page->freelist = start + page->objects * s->size;
+
+ bitmap_fill(map(page), page->objects);
+
+ for_each_object(p, s, start, page->objects)
+ setup_object(s, page, p);
- page->freelist = start;
- page->inuse = 0;
out:
return page;
}
@@ -1306,10 +1328,8 @@ static void add_partial(struct kmem_cach
spin_unlock(&n->list_lock);
}
-static void remove_partial(struct kmem_cache *s, struct page *page)
+static void remove_partial(struct kmem_cache_node *n, struct page *page)
{
- struct kmem_cache_node *n = get_node(s, page_to_nid(page));
-
spin_lock(&n->list_lock);
list_del(&page->lru);
n->nr_partial--;
@@ -1327,7 +1347,6 @@ static inline int lock_and_freeze_slab(s
if (slab_trylock(page)) {
list_del(&page->lru);
n->nr_partial--;
- __SetPageSlubFrozen(page);
return 1;
}
return 0;
@@ -1430,114 +1449,146 @@ static struct page *get_partial(struct k
}
/*
- * Move a page back to the lists.
- *
- * Must be called with the slab lock held.
- *
- * On exit the slab lock will have been dropped.
+ * Move the vector of objects back to the slab pages they came from
*/
-static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
+void drain_objects(struct kmem_cache *s, void **object, int nr)
{
- struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+ int i;
- __ClearPageSlubFrozen(page);
- if (page->inuse) {
+ for (i = 0 ; i < nr; ) {
- if (page->freelist) {
- add_partial(n, page, tail);
- stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
- } else {
- stat(s, DEACTIVATE_FULL);
- if (kmem_cache_debug(s) && (s->flags & SLAB_STORE_USER))
- add_full(n, page);
+ void *p = object[i];
+ struct page *page = virt_to_head_page(p);
+ void *addr = page_address(page);
+ unsigned long size = PAGE_SIZE << compound_order(page);
+ int was_fully_allocated;
+ unsigned long *m;
+ unsigned long offset;
+ struct kmem_cache_node *n;
+
+ if (kmem_cache_debug(s) && !PageSlab(page)) {
+ object_err(s, page, object[i], "Object from non-slab page");
+ i++;
+ continue;
}
- slab_unlock(page);
- } else {
- stat(s, DEACTIVATE_EMPTY);
- if (n->nr_partial < s->min_partial) {
+
+ slab_lock(page);
+ m = map(page);
+ was_fully_allocated = bitmap_empty(m, page->objects);
+
+ offset = p - addr;
+
+ while (i < nr) {
+
+ int bit;
+ unsigned long new_offset;
+
+ if (offset >= size)
+ break;
+
+ if (kmem_cache_debug(s) && offset % s->size) {
+ object_err(s, page, object[i], "Misaligned object");
+ i++;
+ new_offset = object[i] - addr;
+ continue;
+ }
+
+ bit = offset / s->size;
+
/*
- * Adding an empty slab to the partial slabs in order
- * to avoid page allocator overhead. This slab needs
- * to come after the other slabs with objects in
- * so that the others get filled first. That way the
- * size of the partial list stays small.
- *
- * kmem_cache_shrink can reclaim any empty slabs from
- * the partial list.
- */
- add_partial(n, page, 1);
- slab_unlock(page);
- } else {
+ * Fast loop to fold a sequence of objects into the slab
+ * avoiding division and virt_to_head_page()
+ */
+ do {
+
+ if (kmem_cache_debug(s)) {
+ if (unlikely(__test_and_set_bit(bit, m)))
+ object_err(s, page, object[i], "Double free");
+ } else
+ __set_bit(bit, m);
+
+ i++;
+ bit++;
+ offset += s->size;
+ new_offset = object[i] - addr;
+
+ } while (new_offset == offset && i < nr && new_offset < size);
+
+ offset = new_offset;
+ }
+ n = get_node(s, page_to_nid(page));
+ if (bitmap_full(m, page->objects)
+ && n->nr_partial > s->min_partial) {
+
+ /* All objects are available now */
+ if (!was_fully_allocated) {
+
+ remove_partial(n, page);
+ stat(s, FREE_REMOVE_PARTIAL);
+ } else
+ remove_full(s, n, page);
+
slab_unlock(page);
- stat(s, FREE_SLAB);
discard_slab(s, page);
+
+ } else {
+
+ /* Some object are available now */
+ if (was_fully_allocated) {
+
+ /* Slab was had no free objects but has them now */
+ remove_full(s, n, page);
+ add_partial(n, page, 1);
+ stat(s, FREE_ADD_PARTIAL);
+ }
+ slab_unlock(page);
}
}
}
-/*
- * Remove the cpu slab
- */
-static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
+static inline void drain_queue(struct kmem_cache *s, struct kmem_cache_queue *q, int nr)
{
- struct page *page = c->page;
- int tail = 1;
-
- if (page->freelist)
- stat(s, DEACTIVATE_REMOTE_FREES);
- /*
- * Merge cpu freelist into slab freelist. Typically we get here
- * because both freelists are empty. So this is unlikely
- * to occur.
- */
- while (unlikely(c->freelist)) {
- void **object;
+ int t = min(nr, q->objects);
- tail = 0; /* Hot objects. Put the slab first */
+ drain_objects(s, q->object, t);
- /* Retrieve object from cpu_freelist */
- object = c->freelist;
- c->freelist = get_freepointer(s, c->freelist);
-
- /* And put onto the regular freelist */
- set_freepointer(s, object, page->freelist);
- page->freelist = object;
- page->inuse--;
- }
- c->page = NULL;
- unfreeze_slab(s, page, tail);
+ q->objects -= t;
+ if (q->objects)
+ memcpy(q->object, q->object + t,
+ q->objects * sizeof(void *));
}
-
-static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
+/*
+ * Drain all objects from a per cpu queue
+ */
+static void flush_cpu_objects(struct kmem_cache *s, struct kmem_cache_cpu *c)
{
- stat(s, CPUSLAB_FLUSH);
- slab_lock(c->page);
- deactivate_slab(s, c);
+ drain_queue(s, &c->q, c->q.objects);
+ stat(s, QUEUE_FLUSH);
}
/*
- * Flush cpu slab.
+ * Flush cpu objects.
*
* Called from IPI handler with interrupts disabled.
*/
-static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
+static void __flush_cpu_objects(void *d)
{
- struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+ struct kmem_cache *s = d;
+ struct kmem_cache_cpu *c = __this_cpu_ptr(s->cpu_slab);
- if (likely(c && c->page))
- flush_slab(s, c);
+ if (c->q.objects)
+ flush_cpu_objects(s, c);
}
-static void flush_cpu_slab(void *d)
+static void flush_all(struct kmem_cache *s)
{
- struct kmem_cache *s = d;
-
- __flush_cpu_slab(s, smp_processor_id());
+ on_each_cpu(__flush_cpu_objects, s, 1);
}
-static void flush_all(struct kmem_cache *s)
+struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s, int n)
{
- on_each_cpu(flush_cpu_slab, s, 1);
+ return __alloc_percpu(sizeof(struct kmem_cache_cpu),
+ __alignof__(struct kmem_cache_cpu));
}
/*
@@ -1555,7 +1606,7 @@ static inline int node_match(struct kmem
static int count_free(struct page *page)
{
- return page->objects - page->inuse;
+ return available(page);
}
static unsigned long count_partial(struct kmem_cache_node *n,
@@ -1617,139 +1668,149 @@ slab_out_of_memory(struct kmem_cache *s,
}
/*
- * Slow path. The lockless freelist is empty or we need to perform
- * debugging duties.
- *
- * Interrupts are disabled.
- *
- * Processing is still very fast if new objects have been freed to the
- * regular freelist. In that case we simply take over the regular freelist
- * as the lockless freelist and zap the regular freelist.
- *
- * If that is not working then we fall back to the partial lists. We take the
- * first element of the freelist as the object to allocate now and move the
- * rest of the freelist to the lockless freelist.
- *
- * And if we were unable to get a new slab from the partial slab lists then
- * we need to allocate a new slab. This is the slowest path since it involves
- * a call to the page allocator and the setup of a new slab.
- */
-static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
- unsigned long addr, struct kmem_cache_cpu *c)
-{
- void **object;
- struct page *new;
-
- /* We handle __GFP_ZERO in the caller */
- gfpflags &= ~__GFP_ZERO;
-
- if (!c->page)
- goto new_slab;
-
- slab_lock(c->page);
- if (unlikely(!node_match(c, node)))
- goto another_slab;
-
- stat(s, ALLOC_REFILL);
-
-load_freelist:
- object = c->page->freelist;
- if (unlikely(!object))
- goto another_slab;
- if (kmem_cache_debug(s))
- goto debug;
-
- c->freelist = get_freepointer(s, object);
- c->page->inuse = c->page->objects;
- c->page->freelist = NULL;
- c->node = page_to_nid(c->page);
-unlock_out:
- slab_unlock(c->page);
- stat(s, ALLOC_SLOWPATH);
- return object;
+ * Retrieve pointers to nr objects from a slab into the object array.
+ * Slab must be locked.
+ */
+void retrieve_objects(struct kmem_cache *s, struct page *page, void **object, int nr)
+{
+ void *addr = page_address(page);
+ unsigned long *m = map(page);
+
+ while (nr > 0) {
+ int i = find_first_bit(m, page->objects);
+ void *a;
-another_slab:
- deactivate_slab(s, c);
+ __clear_bit(i, m);
+ a = addr + i * s->size;
-new_slab:
- new = get_partial(s, gfpflags, node);
- if (new) {
- c->page = new;
- stat(s, ALLOC_FROM_PARTIAL);
- goto load_freelist;
- }
-
- gfpflags &= gfp_allowed_mask;
- if (gfpflags & __GFP_WAIT)
- local_irq_enable();
-
- new = new_slab(s, gfpflags, node);
-
- if (gfpflags & __GFP_WAIT)
- local_irq_disable();
-
- if (new) {
- c = __this_cpu_ptr(s->cpu_slab);
- stat(s, ALLOC_SLAB);
- if (c->page)
- flush_slab(s, c);
- slab_lock(new);
- __SetPageSlubFrozen(new);
- c->page = new;
- goto load_freelist;
+ /*
+ * Fast loop to get a sequence of objects out of the slab
+ * without find_first_bit() and multiplication
+ */
+ do {
+ nr--;
+ object[nr] = a;
+ a += s->size;
+ i++;
+ } while (nr > 0 && i < page->objects && __test_and_clear_bit(i, m));
}
- if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
- slab_out_of_memory(s, gfpflags, node);
- return NULL;
-debug:
- if (!alloc_debug_processing(s, c->page, object, addr))
- goto another_slab;
+}
+
+static inline void refill_queue(struct kmem_cache *s,
+ struct kmem_cache_queue *q, struct page *page, int nr)
+{
+ int d;
- c->page->inuse++;
- c->page->freelist = get_freepointer(s, object);
- c->node = -1;
- goto unlock_out;
+ d = min(BATCH_SIZE - q->objects, nr);
+ retrieve_objects(s, page, q->object + q->objects, d);
+ q->objects += d;
}
-/*
- * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
- * have the fastpath folded into their functions. So no function call
- * overhead for requests that can be satisfied on the fastpath.
- *
- * The fastpath works by first checking if the lockless freelist can be used.
- * If not then __slab_alloc is called for slow processing.
- *
- * Otherwise we can simply pick the next object from the lockless free list.
- */
-static __always_inline void *slab_alloc(struct kmem_cache *s,
+void to_lists(struct kmem_cache *s, struct page *page, int tail)
+{
+ if (!all_objects_used(page))
+
+ add_partial(get_node(s, page_to_nid(page)), page, tail);
+
+ else
+ add_full(s, get_node(s, page_to_nid(page)), page);
+}
+
+/* Handling of objects from other nodes */
+
+static void slab_free_alien(struct kmem_cache *s,
+ struct kmem_cache_cpu *c, struct page *page, void *object, int node)
+{
+#ifdef CONFIG_NUMA
+ /* Direct free to the slab */
+ drain_objects(s, &object, 1);
+#endif
+}
+
+/* Generic allocation */
+
+static void *slab_alloc(struct kmem_cache *s,
gfp_t gfpflags, int node, unsigned long addr)
{
- void **object;
+ void *object;
struct kmem_cache_cpu *c;
+ struct kmem_cache_queue *q;
unsigned long flags;
if (slab_pre_alloc_hook(s, gfpflags))
return NULL;
+redo:
local_irq_save(flags);
c = __this_cpu_ptr(s->cpu_slab);
- object = c->freelist;
- if (unlikely(!object || !node_match(c, node)))
+ q = &c->q;
+ if (unlikely(queue_empty(q) || !node_match(c, node))) {
- object = __slab_alloc(s, gfpflags, node, addr, c);
+ if (unlikely(!node_match(c, node))) {
+ flush_cpu_objects(s, c);
+ c->node = node;
+ }
- else {
- c->freelist = get_freepointer(s, object);
+ while (q->objects < BATCH_SIZE) {
+ struct page *new;
+
+ new = get_partial(s, gfpflags & ~__GFP_ZERO, node);
+ if (unlikely(!new)) {
+
+ gfpflags &= gfp_allowed_mask;
+
+ if (gfpflags & __GFP_WAIT)
+ local_irq_enable();
+
+ new = new_slab(s, gfpflags, node);
+
+ if (gfpflags & __GFP_WAIT)
+ local_irq_disable();
+
+ /* process may have moved to different cpu */
+ c = __this_cpu_ptr(s->cpu_slab);
+ q = &c->q;
+
+ if (!new) {
+ if (queue_empty(q))
+ goto oom;
+ break;
+ }
+ stat(s, ALLOC_SLAB);
+ slab_lock(new);
+ } else
+ stat(s, ALLOC_FROM_PARTIAL);
+
+ refill_queue(s, q, new, available(new));
+ to_lists(s, new, 1);
+
+ slab_unlock(new);
+ }
+ stat(s, ALLOC_SLOWPATH);
+
+ } else
stat(s, ALLOC_FASTPATH);
+
+ object = queue_get(q);
+
+ if (kmem_cache_debug(s)) {
+ if (!alloc_debug_processing(s, object, addr))
+ goto redo;
}
local_irq_restore(flags);
- if (unlikely(gfpflags & __GFP_ZERO) && object)
+ if (unlikely(gfpflags & __GFP_ZERO))
memset(object, 0, s->objsize);
slab_post_alloc_hook(s, gfpflags, object);
return object;
+
+oom:
+ local_irq_restore(flags);
+ if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
+ slab_out_of_memory(s, gfpflags, node);
+ return NULL;
}
void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
@@ -1793,114 +1854,52 @@ void *kmem_cache_alloc_node_notrace(stru
EXPORT_SYMBOL(kmem_cache_alloc_node_notrace);
#endif
-/*
- * Slow patch handling. This may still be called frequently since objects
- * have a longer lifetime than the cpu slabs in most processing loads.
- *
- * So we still attempt to reduce cache line usage. Just take the slab
- * lock and free the item. If there is no additional partial page
- * handling required then we can return immediately.
- */
-static void __slab_free(struct kmem_cache *s, struct page *page,
+static void slab_free(struct kmem_cache *s, struct page *page,
void *x, unsigned long addr)
{
- void *prior;
- void **object = (void *)x;
-
- stat(s, FREE_SLOWPATH);
- slab_lock(page);
+ struct kmem_cache_cpu *c;
+ struct kmem_cache_queue *q;
+ unsigned long flags;
- if (kmem_cache_debug(s))
- goto debug;
+ slab_free_hook(s, x);
-checks_ok:
- prior = page->freelist;
- set_freepointer(s, object, prior);
- page->freelist = object;
- page->inuse--;
-
- if (unlikely(PageSlubFrozen(page))) {
- stat(s, FREE_FROZEN);
- goto out_unlock;
- }
+ local_irq_save(flags);
+ if (kmem_cache_debug(s)
+ && !free_debug_processing(s, page, x, addr))
+ goto out;
- if (unlikely(!page->inuse))
- goto slab_empty;
+ slab_free_hook_irq(s, x);
- /*
- * Objects left in the slab. If it was not on the partial list before
- * then add it.
- */
- if (unlikely(!prior)) {
- add_partial(get_node(s, page_to_nid(page)), page, 1);
- stat(s, FREE_ADD_PARTIAL);
- }
+ c = __this_cpu_ptr(s->cpu_slab);
-out_unlock:
- slab_unlock(page);
- return;
+ if (NUMA_BUILD) {
+ int node = page_to_nid(page);
-slab_empty:
- if (prior) {
- /*
- * Slab still on the partial list.
- */
- remove_partial(s, page);
- stat(s, FREE_REMOVE_PARTIAL);
+ if (unlikely(node != c->node)) {
+ slab_free_alien(s, c, page, x, node);
+ stat(s, FREE_ALIEN);
+ goto out;
+ }
}
- slab_unlock(page);
- stat(s, FREE_SLAB);
- discard_slab(s, page);
- return;
-
-debug:
- if (!free_debug_processing(s, page, x, addr))
- goto out_unlock;
- goto checks_ok;
-}
-
-/*
- * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
- * can perform fastpath freeing without additional function calls.
- *
- * The fastpath is only possible if we are freeing to the current cpu slab
- * of this processor. This typically the case if we have just allocated
- * the item before.
- *
- * If fastpath is not possible then fall back to __slab_free where we deal
- * with all sorts of special processing.
- */
-static __always_inline void slab_free(struct kmem_cache *s,
- struct page *page, void *x, unsigned long addr)
-{
- void **object = (void *)x;
- struct kmem_cache_cpu *c;
- unsigned long flags;
- slab_free_hook(s, x);
+ q = &c->q;
- local_irq_save(flags);
- c = __this_cpu_ptr(s->cpu_slab);
+ if (unlikely(queue_full(q))) {
- slab_free_hook_irq(s, x);
+ drain_queue(s, q, BATCH_SIZE);
+ stat(s, FREE_SLOWPATH);
- if (likely(page == c->page && c->node >= 0)) {
- set_freepointer(s, object, c->freelist);
- c->freelist = object;
- stat(s, FREE_FASTPATH);
} else
- __slab_free(s, page, x, addr);
+ stat(s, FREE_FASTPATH);
+ queue_put(q, x);
+out:
local_irq_restore(flags);
}
void kmem_cache_free(struct kmem_cache *s, void *x)
{
- struct page *page;
-
- page = virt_to_head_page(x);
-
- slab_free(s, page, x, _RET_IP_);
+ slab_free(s, virt_to_head_page(x), x, _RET_IP_);
trace_kmem_cache_free(_RET_IP_, x);
}
@@ -1918,11 +1917,6 @@ static struct page *get_object_page(cons
}
/*
- * Object placement in a slab is made very easy because we always start at
- * offset 0. If we tune the size of the object to the alignment then we can
- * get the required alignment by putting one properly sized object after
- * another.
- *
* Notice that the allocation order determines the sizes of the per cpu
* caches. Each processor has always one slab available for allocations.
* Increasing the allocation order reduces the number of times that slabs
@@ -2017,7 +2011,7 @@ static inline int calculate_order(int si
*/
min_objects = slub_min_objects;
if (!min_objects)
- min_objects = 4 * (fls(nr_cpu_ids) + 1);
+ min_objects = min(BITS_PER_LONG, 4 * (fls(nr_cpu_ids) + 1));
max_objects = (PAGE_SIZE << slub_max_order)/size;
min_objects = min(min_objects, max_objects);
@@ -2129,10 +2123,7 @@ static void early_kmem_cache_node_alloc(
"in order to be able to continue\n");
}
- n = page->freelist;
- BUG_ON(!n);
- page->freelist = get_freepointer(kmem_cache_node, n);
- page->inuse++;
+ retrieve_objects(kmem_cache_node, page, (void **)&n, 1);
kmem_cache_node->node[node] = n;
#ifdef CONFIG_SLUB_DEBUG
init_object(kmem_cache_node, n, 1);
@@ -2217,10 +2208,11 @@ static void set_min_partial(struct kmem_
static int calculate_sizes(struct kmem_cache *s, int forced_order)
{
unsigned long flags = s->flags;
- unsigned long size = s->objsize;
+ unsigned long size;
unsigned long align = s->align;
int order;
+ size = s->objsize;
/*
* Round up object size to the next word boundary. We can only
* place the free pointer at word boundaries and this determines
@@ -2252,24 +2244,10 @@ static int calculate_sizes(struct kmem_c
/*
* With that we have determined the number of bytes in actual use
- * by the object. This is the potential offset to the free pointer.
+ * by the object.
*/
s->inuse = size;
- if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
- s->ctor)) {
- /*
- * Relocate free pointer after the object if it is not
- * permitted to overwrite the first word of the object on
- * kmem_cache_free.
- *
- * This is the case if we do RCU, have a constructor or
- * destructor or are poisoning the objects.
- */
- s->offset = size;
- size += sizeof(void *);
- }
-
#ifdef CONFIG_SLUB_DEBUG
if (flags & SLAB_STORE_USER)
/*
@@ -2355,7 +2333,6 @@ static int kmem_cache_open(struct kmem_c
*/
if (get_order(s->size) > get_order(s->objsize)) {
s->flags &= ~DEBUG_METADATA_FLAGS;
- s->offset = 0;
if (!calculate_sizes(s, -1))
goto error;
}
@@ -2380,9 +2357,9 @@ static int kmem_cache_open(struct kmem_c
error:
if (flags & SLAB_PANIC)
panic("Cannot create slab %s size=%lu realsize=%u "
- "order=%u offset=%u flags=%lx\n",
+ "order=%u flags=%lx\n",
s->name, (unsigned long)size, s->size, oo_order(s->oo),
- s->offset, flags);
+ flags);
return 0;
}
@@ -2436,19 +2413,14 @@ static void list_slab_objects(struct kme
#ifdef CONFIG_SLUB_DEBUG
void *addr = page_address(page);
void *p;
- long *map = kzalloc(BITS_TO_LONGS(page->objects) * sizeof(long),
- GFP_ATOMIC);
+ long *m = map(page);
- if (!map)
- return;
slab_err(s, page, "%s", text);
slab_lock(page);
- for_each_free_object(p, s, page->freelist)
- set_bit(slab_index(p, s, addr), map);
for_each_object(p, s, addr, page->objects) {
- if (!test_bit(slab_index(p, s, addr), map)) {
+ if (!test_bit(slab_index(p, s, addr), m)) {
printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
p, p - addr);
print_tracking(s, p);
@@ -2469,7 +2441,7 @@ static void free_partial(struct kmem_cac
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry_safe(page, h, &n->partial, lru) {
- if (!page->inuse) {
+ if (all_objects_available(page)) {
list_del(&page->lru);
discard_slab(s, page);
n->nr_partial--;
@@ -2824,7 +2796,7 @@ int kmem_cache_shrink(struct kmem_cache
* list_lock. page->inuse here is the upper limit.
*/
list_for_each_entry_safe(page, t, &n->partial, lru) {
- if (!page->inuse && slab_trylock(page)) {
+ if (all_objects_available(page) && slab_trylock(page)) {
/*
* Must hold slab lock here because slab_free
* may have freed the last object and be
@@ -2836,7 +2808,7 @@ int kmem_cache_shrink(struct kmem_cache
discard_slab(s, page);
} else {
list_move(&page->lru,
- slabs_by_inuse + page->inuse);
+ slabs_by_inuse + inuse(page));
}
}
@@ -3312,7 +3284,7 @@ static int __cpuinit slab_cpuup_callback
down_read(&slub_lock);
list_for_each_entry(s, &slab_caches, list) {
local_irq_save(flags);
- __flush_cpu_slab(s, cpu);
+ flush_cpu_objects(s, per_cpu_ptr(s->cpu_slab ,cpu));
local_irq_restore(flags);
}
up_read(&slub_lock);
@@ -3382,7 +3354,7 @@ void *__kmalloc_node_track_caller(size_t
#ifdef CONFIG_SLUB_DEBUG
static int count_inuse(struct page *page)
{
- return page->inuse;
+ return inuse(page);
}
static int count_total(struct page *page)
@@ -3390,54 +3362,52 @@ static int count_total(struct page *page
return page->objects;
}
-static int validate_slab(struct kmem_cache *s, struct page *page,
- unsigned long *map)
+static int validate_slab(struct kmem_cache *s, struct page *page)
{
void *p;
void *addr = page_address(page);
+ unsigned long *m = map(page);
+ unsigned long errors = 0;
- if (!check_slab(s, page) ||
- !on_freelist(s, page, NULL))
+ if (!check_slab(s, page) || !verify_slab(s, page))
return 0;
- /* Now we know that a valid freelist exists */
- bitmap_zero(map, page->objects);
+ for_each_object(p, s, addr, page->objects) {
+ int bit = slab_index(p, s, addr);
+ int used = !test_bit(bit, m);
- for_each_free_object(p, s, page->freelist) {
- set_bit(slab_index(p, s, addr), map);
- if (!check_object(s, page, p, 0))
- return 0;
+ if (!check_object(s, page, p, used))
+ errors++;
}
- for_each_object(p, s, addr, page->objects)
- if (!test_bit(slab_index(p, s, addr), map))
- if (!check_object(s, page, p, 1))
- return 0;
- return 1;
+ return errors;
}
-static void validate_slab_slab(struct kmem_cache *s, struct page *page,
- unsigned long *map)
+static unsigned long validate_slab_slab(struct kmem_cache *s, struct page *page)
{
+ unsigned long errors = 0;
+
if (slab_trylock(page)) {
- validate_slab(s, page, map);
+ errors = validate_slab(s, page);
slab_unlock(page);
} else
printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
s->name, page);
+ return errors;
}
static int validate_slab_node(struct kmem_cache *s,
- struct kmem_cache_node *n, unsigned long *map)
+ struct kmem_cache_node *n)
{
unsigned long count = 0;
struct page *page;
unsigned long flags;
+ unsigned long errors;
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry(page, &n->partial, lru) {
- validate_slab_slab(s, page, map);
+ errors += validate_slab_slab(s, page);
count++;
}
if (count != n->nr_partial)
@@ -3448,7 +3418,7 @@ static int validate_slab_node(struct kme
goto out;
list_for_each_entry(page, &n->full, lru) {
- validate_slab_slab(s, page, map);
+ validate_slab_slab(s, page);
count++;
}
if (count != atomic_long_read(&n->nr_slabs))
@@ -3458,26 +3428,20 @@ static int validate_slab_node(struct kme
out:
spin_unlock_irqrestore(&n->list_lock, flags);
- return count;
+ return errors;
}
static long validate_slab_cache(struct kmem_cache *s)
{
int node;
unsigned long count = 0;
- unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
- sizeof(unsigned long), GFP_KERNEL);
-
- if (!map)
- return -ENOMEM;
flush_all(s);
for_each_node_state(node, N_NORMAL_MEMORY) {
struct kmem_cache_node *n = get_node(s, node);
- count += validate_slab_node(s, n, map);
+ count += validate_slab_node(s, n);
}
- kfree(map);
return count;
}
@@ -3666,18 +3630,14 @@ static int add_location(struct loc_track
}
static void process_slab(struct loc_track *t, struct kmem_cache *s,
- struct page *page, enum track_item alloc,
- long *map)
+ struct page *page, enum track_item alloc)
{
void *addr = page_address(page);
+ unsigned long *m = map(page);
void *p;
- bitmap_zero(map, page->objects);
- for_each_free_object(p, s, page->freelist)
- set_bit(slab_index(p, s, addr), map);
-
for_each_object(p, s, addr, page->objects)
- if (!test_bit(slab_index(p, s, addr), map))
+ if (!test_bit(slab_index(p, s, addr), m))
add_location(t, s, get_track(s, p, alloc));
}
@@ -3688,12 +3648,9 @@ static int list_locations(struct kmem_ca
unsigned long i;
struct loc_track t = { 0, 0, NULL };
int node;
- unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
- sizeof(unsigned long), GFP_KERNEL);
- if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
+ if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
GFP_TEMPORARY)) {
- kfree(map);
return sprintf(buf, "Out of memory\n");
}
/* Push back cpu slabs */
@@ -3709,9 +3666,9 @@ static int list_locations(struct kmem_ca
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry(page, &n->partial, lru)
- process_slab(&t, s, page, alloc, map);
+ process_slab(&t, s, page, alloc);
list_for_each_entry(page, &n->full, lru)
- process_slab(&t, s, page, alloc, map);
+ process_slab(&t, s, page, alloc);
spin_unlock_irqrestore(&n->list_lock, flags);
}
@@ -3762,7 +3719,6 @@ static int list_locations(struct kmem_ca
}
free_loc_track(&t);
- kfree(map);
if (!t.count)
len += sprintf(buf, "No data\n");
return len;
@@ -3778,7 +3734,6 @@ enum slab_stat_type {
#define SO_ALL (1 << SL_ALL)
#define SO_PARTIAL (1 << SL_PARTIAL)
-#define SO_CPU (1 << SL_CPU)
#define SO_OBJECTS (1 << SL_OBJECTS)
#define SO_TOTAL (1 << SL_TOTAL)
@@ -3796,30 +3751,6 @@ static ssize_t show_slab_objects(struct
return -ENOMEM;
per_cpu = nodes + nr_node_ids;
- if (flags & SO_CPU) {
- int cpu;
-
- for_each_possible_cpu(cpu) {
- struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
-
- if (!c || c->node < 0)
- continue;
-
- if (c->page) {
- if (flags & SO_TOTAL)
- x = c->page->objects;
- else if (flags & SO_OBJECTS)
- x = c->page->inuse;
- else
- x = 1;
-
- total += x;
- nodes[c->node] += x;
- }
- per_cpu[c->node]++;
- }
- }
-
if (flags & SO_ALL) {
for_each_node_state(node, N_NORMAL_MEMORY) {
struct kmem_cache_node *n = get_node(s, node);
@@ -3989,11 +3920,35 @@ static ssize_t partial_show(struct kmem_
}
SLAB_ATTR_RO(partial);
-static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
+static ssize_t cpu_queues_show(struct kmem_cache *s, char *buf)
{
- return show_slab_objects(s, buf, SO_CPU);
+ unsigned long total = 0;
+ int x;
+ int cpu;
+ unsigned long *cpus;
+
+ cpus = kzalloc(1 * sizeof(unsigned long) * nr_cpu_ids, GFP_KERNEL);
+ if (!cpus)
+ return -ENOMEM;
+
+ for_each_online_cpu(cpu) {
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+
+ total += c->q.objects;
+ }
+
+ x = sprintf(buf, "%lu", total);
+
+ for_each_online_cpu(cpu) {
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+
+ if (c->q.objects)
+ x += sprintf(buf + x, " C%d=%u", cpu, c->q.objects);
+ }
+ kfree(cpus);
+ return x + sprintf(buf + x, "\n");
}
-SLAB_ATTR_RO(cpu_slabs);
+SLAB_ATTR_RO(cpu_queues);
static ssize_t objects_show(struct kmem_cache *s, char *buf)
{
@@ -4287,19 +4242,12 @@ STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath
STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
STAT_ATTR(FREE_FASTPATH, free_fastpath);
STAT_ATTR(FREE_SLOWPATH, free_slowpath);
-STAT_ATTR(FREE_FROZEN, free_frozen);
STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
STAT_ATTR(ALLOC_SLAB, alloc_slab);
-STAT_ATTR(ALLOC_REFILL, alloc_refill);
STAT_ATTR(FREE_SLAB, free_slab);
-STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
-STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
-STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
-STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
-STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
-STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
+STAT_ATTR(QUEUE_FLUSH, queue_flush);
STAT_ATTR(ORDER_FALLBACK, order_fallback);
#endif
@@ -4314,7 +4262,7 @@ static struct attribute *slab_attrs[] =
&total_objects_attr.attr,
&slabs_attr.attr,
&partial_attr.attr,
- &cpu_slabs_attr.attr,
+ &cpu_queues_attr.attr,
&ctor_attr.attr,
&aliases_attr.attr,
&align_attr.attr,
@@ -4341,19 +4289,12 @@ static struct attribute *slab_attrs[] =
&alloc_slowpath_attr.attr,
&free_fastpath_attr.attr,
&free_slowpath_attr.attr,
- &free_frozen_attr.attr,
&free_add_partial_attr.attr,
&free_remove_partial_attr.attr,
&alloc_from_partial_attr.attr,
&alloc_slab_attr.attr,
- &alloc_refill_attr.attr,
&free_slab_attr.attr,
- &cpuslab_flush_attr.attr,
- &deactivate_full_attr.attr,
- &deactivate_empty_attr.attr,
- &deactivate_to_head_attr.attr,
- &deactivate_to_tail_attr.attr,
- &deactivate_remote_frees_attr.attr,
+ &queue_flush_attr.attr,
&order_fallback_attr.attr,
#endif
#ifdef CONFIG_FAILSLAB
Index: linux-2.6/include/linux/page-flags.h
===================================================================
--- linux-2.6.orig/include/linux/page-flags.h 2010-08-19 20:10:20.000000000 -0500
+++ linux-2.6/include/linux/page-flags.h 2010-08-19 20:10:23.000000000 -0500
@@ -125,9 +125,6 @@ enum pageflags {
/* SLOB */
PG_slob_free = PG_private,
-
- /* SLUB */
- PG_slub_frozen = PG_active,
};
#ifndef __GENERATING_BOUNDS_H
@@ -213,8 +210,6 @@ PAGEFLAG(SwapBacked, swapbacked) __CLEAR
__PAGEFLAG(SlobFree, slob_free)
-__PAGEFLAG(SlubFrozen, slub_frozen)
-
/*
* Private page markings that may be used by the filesystem that owns the page
* for its own purposes.
Index: linux-2.6/include/linux/slub_def.h
===================================================================
--- linux-2.6.orig/include/linux/slub_def.h 2010-08-19 20:10:20.000000000 -0500
+++ linux-2.6/include/linux/slub_def.h 2010-08-19 20:10:23.000000000 -0500
@@ -2,9 +2,10 @@
#define _LINUX_SLUB_DEF_H
/*
- * SLUB : A Slab allocator without object queues.
+ * SLUB : The Unified Slab allocator.
*
- * (C) 2007 SGI, Christoph Lameter
+ * (C) 2007-2008 SGI, Christoph Lameter
+ * (C) 2008-2010 Linux Foundation, Christoph Lameter
*/
#include <linux/types.h>
#include <linux/gfp.h>
@@ -15,33 +16,36 @@
#include <trace/events/kmem.h>
enum stat_item {
- ALLOC_FASTPATH, /* Allocation from cpu slab */
- ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */
- FREE_FASTPATH, /* Free to cpu slub */
- FREE_SLOWPATH, /* Freeing not to cpu slab */
- FREE_FROZEN, /* Freeing to frozen slab */
- FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
- FREE_REMOVE_PARTIAL, /* Freeing removes last object */
- ALLOC_FROM_PARTIAL, /* Cpu slab acquired from partial list */
- ALLOC_SLAB, /* Cpu slab acquired from page allocator */
- ALLOC_REFILL, /* Refill cpu slab from slab freelist */
+ ALLOC_FASTPATH, /* Allocation from cpu queue */
+ ALLOC_SLOWPATH, /* Allocation required refilling of queue */
+ FREE_FASTPATH, /* Free to cpu queue */
+ FREE_SLOWPATH, /* Required pushing objects out of the queue */
+ FREE_ADD_PARTIAL, /* Freeing moved slab to partial list */
+ FREE_REMOVE_PARTIAL, /* Freeing removed from partial list */
+ ALLOC_FROM_PARTIAL, /* slab with objects acquired from partial */
+ ALLOC_SLAB, /* New slab acquired from page allocator */
+ FREE_ALIEN, /* Free to alien node */
FREE_SLAB, /* Slab freed to the page allocator */
- CPUSLAB_FLUSH, /* Abandoning of the cpu slab */
- DEACTIVATE_FULL, /* Cpu slab was full when deactivated */
- DEACTIVATE_EMPTY, /* Cpu slab was empty when deactivated */
- DEACTIVATE_TO_HEAD, /* Cpu slab was moved to the head of partials */
- DEACTIVATE_TO_TAIL, /* Cpu slab was moved to the tail of partials */
- DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
+ QUEUE_FLUSH, /* Flushing of the per cpu queue */
ORDER_FALLBACK, /* Number of times fallback was necessary */
NR_SLUB_STAT_ITEMS };
+#define QUEUE_SIZE 50
+#define BATCH_SIZE 25
+
+/* Queueing structure used for per cpu, l3 cache and alien queueing */
+struct kmem_cache_queue {
+ int objects; /* Available objects */
+ int max; /* Queue capacity */
+ void *object[QUEUE_SIZE];
+};
+
struct kmem_cache_cpu {
- void **freelist; /* Pointer to first free per cpu object */
- struct page *page; /* The slab from which we are allocating */
- int node; /* The node of the page (or -1 for debug) */
#ifdef CONFIG_SLUB_STATS
unsigned stat[NR_SLUB_STAT_ITEMS];
#endif
+ int node; /* objects only from this numa node */
+ struct kmem_cache_queue q;
};
struct kmem_cache_node {
@@ -73,8 +77,8 @@ struct kmem_cache {
unsigned long flags;
int size; /* The size of an object including meta data */
int objsize; /* The size of an object without meta data */
- int offset; /* Free pointer offset. */
struct kmem_cache_order_objects oo;
+ int batch; /* batch size */
/* Allocation and freeing of slabs */
struct kmem_cache_order_objects max;
Index: linux-2.6/init/Kconfig
===================================================================
--- linux-2.6.orig/init/Kconfig 2010-08-19 20:10:20.000000000 -0500
+++ linux-2.6/init/Kconfig 2010-08-19 20:10:23.000000000 -0500
@@ -1091,14 +1091,14 @@ config SLAB
per cpu and per node queues.
config SLUB
- bool "SLUB (Unqueued Allocator)"
+ bool "SLUB (Unified allocator)"
help
- SLUB is a slab allocator that minimizes cache line usage
- instead of managing queues of cached objects (SLAB approach).
- Per cpu caching is realized using slabs of objects instead
- of queues of objects. SLUB can use memory efficiently
- and has enhanced diagnostics. SLUB is the default choice for
- a slab allocator.
+ SLUB is a slab allocator that minimizes metadata and provides
+ a clean implementation that is faster than SLAB. SLUB has many
+ of the queueing characteristic of the original SLAB allocator
+ but uses a bit map to manage objects in slabs. SLUB can use
+ memory more efficiently and has enhanced diagnostic and
+ resiliency features compared with SLAB.
config SLOB
depends on EMBEDDED
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [S+Q Core 2/6] slub: Allow resizing of per cpu queues
2010-08-20 19:01 [S+Q Core 0/6] SLUB: Queueing Core Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 1/6] slub: Add per cpu queueing Christoph Lameter
@ 2010-08-20 19:01 ` Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 3/6] slub: Get rid of useless function count_free() Christoph Lameter
` (3 subsequent siblings)
5 siblings, 0 replies; 8+ messages in thread
From: Christoph Lameter @ 2010-08-20 19:01 UTC (permalink / raw)
To: Pekka Enberg; +Cc: linux-mm, David Rientjes
[-- Attachment #1: unified_resize --]
[-- Type: text/plain, Size: 13931 bytes --]
Allow resizing of cpu queue and batch size. This is done in the
basic steps that are also followed by SLAB.
Careful: The ->cpu pointer is becoming volatile. References
to the ->cpu pointer either
A. Occur with interrupts disabled. This guarantees that nothing on the
processor itself interferes. This only serializes access to a single
processor specific area.
B. Occur with slub_lock taken for operations on all per cpu areas.
Taking the slub_lock guarantees that no resizing operation will occur
while accessing the percpu areas. The data in the percpu areas
is volatile even with slub_lock since the alloc and free functions
do not take slub_lock and will operate on fields of kmem_cache_cpu.
C. Are racy: Tolerable for statistics. The ->cpu pointer must always
point to a valid kmem_cache_cpu area.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
include/linux/slub_def.h | 9 -
mm/slub.c | 218 +++++++++++++++++++++++++++++++++++++++++------
2 files changed, 197 insertions(+), 30 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2010-08-19 16:34:15.000000000 -0500
+++ linux-2.6/mm/slub.c 2010-08-19 16:34:20.000000000 -0500
@@ -193,10 +193,19 @@ static inline void sysfs_slab_remove(str
#endif
+/*
+ * We allow stat calls while slub_lock is taken or while interrupts
+ * are enabled for simplicities sake.
+ *
+ * This results in potential inaccuracies. If the platform does not
+ * support per cpu atomic operations vs. interrupts then the counters
+ * may be updated in a racy manner due to slab processing in
+ * interrupts.
+ */
static inline void stat(struct kmem_cache *s, enum stat_item si)
{
#ifdef CONFIG_SLUB_STATS
- __this_cpu_inc(s->cpu_slab->stat[si]);
+ __this_cpu_inc(s->cpu->stat[si]);
#endif
}
@@ -301,7 +310,7 @@ static inline void queue_put(struct kmem
static inline int queue_full(struct kmem_cache_queue *q)
{
- return q->objects == QUEUE_SIZE;
+ return q->objects == q->max;
}
static inline int queue_empty(struct kmem_cache_queue *q)
@@ -1566,6 +1575,11 @@ static void flush_cpu_objects(struct kme
stat(s, QUEUE_FLUSH);
}
+struct flush_control {
+ struct kmem_cache *s;
+ struct kmem_cache_cpu *c;
+};
+
/*
* Flush cpu objects.
*
@@ -1573,22 +1587,96 @@ static void flush_cpu_objects(struct kme
*/
static void __flush_cpu_objects(void *d)
{
- struct kmem_cache *s = d;
- struct kmem_cache_cpu *c = __this_cpu_ptr(s->cpu_slab);
+ struct flush_control *f = d;
+ struct kmem_cache_cpu *c = __this_cpu_ptr(f->c);
if (c->q.objects)
- flush_cpu_objects(s, c);
+ flush_cpu_objects(f->s, c);
}
static void flush_all(struct kmem_cache *s)
{
- on_each_cpu(__flush_cpu_objects, s, 1);
+ struct flush_control f = { s, s->cpu };
+
+ on_each_cpu(__flush_cpu_objects, &f, 1);
}
struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s, int n)
{
- return __alloc_percpu(sizeof(struct kmem_cache_cpu),
- __alignof__(struct kmem_cache_cpu));
+ struct kmem_cache_cpu *k;
+ int cpu;
+ int size;
+ int max;
+
+ /* Size the queue and the allocation to cacheline sizes */
+ size = ALIGN(n * sizeof(void *) + sizeof(struct kmem_cache_cpu), cache_line_size());
+
+ k = __alloc_percpu(size, cache_line_size());
+ if (!k)
+ return NULL;
+
+ max = (size - sizeof(struct kmem_cache_cpu)) / sizeof(void *);
+
+ for_each_possible_cpu(cpu) {
+ struct kmem_cache_cpu *c = per_cpu_ptr(k, cpu);
+
+ c->q.max = max;
+ }
+
+ s->cpu_queue = max;
+ return k;
+}
+
+
+static void resize_cpu_queue(struct kmem_cache *s, int queue)
+{
+ struct kmem_cache_cpu *n = alloc_kmem_cache_cpu(s, queue);
+ struct flush_control f;
+
+ /* Create the new cpu queue and then free the old one */
+ f.s = s;
+ f.c = s->cpu;
+
+ /* We can only shrink the queue here since the new
+ * queue size may be smaller and there may be concurrent
+ * slab operations. The update of the queue must be seen
+ * before the change of the location of the percpu queue.
+ *
+ * Note that the queue may contain more object than the
+ * queue size after this operation.
+ */
+ if (queue < s->queue) {
+ s->queue = queue;
+ s->batch = (s->queue + 1) / 2;
+ barrier();
+ }
+
+ /* This is critical since allocation and free runs
+ * concurrently without taking the slub_lock!
+ * We point the cpu pointer to a different per cpu
+ * segment to redirect current processing and then
+ * flush the cpu objects on the old cpu structure.
+ *
+ * The old percpu structure is no longer reachable
+ * since slab_alloc/free must have terminated in order
+ * to execute __flush_cpu_objects. Both require
+ * interrupts to be disabled.
+ */
+ s->cpu = n;
+ on_each_cpu(__flush_cpu_objects, &f, 1);
+
+ /*
+ * If the queue needs to be extended then we deferred
+ * the update until now when the larger sized queue
+ * has been allocated and is working.
+ */
+ if (queue > s->queue) {
+ s->queue = queue;
+ s->batch = (s->queue + 1) / 2;
+ }
+
+ if (slab_state > UP)
+ free_percpu(f.c);
}
/*
@@ -1701,7 +1789,7 @@ static inline void refill_queue(struct k
{
int d;
- d = min(BATCH_SIZE - q->objects, nr);
+ d = min(s->batch - q->objects, nr);
retrieve_objects(s, page, q->object + q->objects, d);
q->objects += d;
}
@@ -1742,7 +1830,7 @@ static void *slab_alloc(struct kmem_cach
redo:
local_irq_save(flags);
- c = __this_cpu_ptr(s->cpu_slab);
+ c = __this_cpu_ptr(s->cpu);
q = &c->q;
if (unlikely(queue_empty(q) || !node_match(c, node))) {
@@ -1751,7 +1839,7 @@ redo:
c->node = node;
}
- while (q->objects < BATCH_SIZE) {
+ while (q->objects < s->batch) {
struct page *new;
new = get_partial(s, gfpflags & ~__GFP_ZERO, node);
@@ -1768,7 +1856,7 @@ redo:
local_irq_disable();
/* process may have moved to different cpu */
- c = __this_cpu_ptr(s->cpu_slab);
+ c = __this_cpu_ptr(s->cpu);
q = &c->q;
if (!new) {
@@ -1870,7 +1958,7 @@ static void slab_free(struct kmem_cache
slab_free_hook_irq(s, x);
- c = __this_cpu_ptr(s->cpu_slab);
+ c = __this_cpu_ptr(s->cpu);
if (NUMA_BUILD) {
int node = page_to_nid(page);
@@ -1886,7 +1974,7 @@ static void slab_free(struct kmem_cache
if (unlikely(queue_full(q))) {
- drain_queue(s, q, BATCH_SIZE);
+ drain_queue(s, q, s->batch);
stat(s, FREE_SLOWPATH);
} else
@@ -2088,9 +2176,9 @@ static inline int alloc_kmem_cache_cpus(
BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
- s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);
+ s->cpu = alloc_kmem_cache_cpu(s, s->queue);
- return s->cpu_slab != NULL;
+ return s->cpu != NULL;
}
#ifdef CONFIG_NUMA
@@ -2312,6 +2400,18 @@ static int calculate_sizes(struct kmem_c
}
+static int initial_queue_size(int size)
+{
+ if (size > PAGE_SIZE)
+ return 8;
+ else if (size > 1024)
+ return 24;
+ else if (size > 256)
+ return 54;
+ else
+ return 120;
+}
+
static int kmem_cache_open(struct kmem_cache *s,
const char *name, size_t size,
size_t align, unsigned long flags,
@@ -2350,6 +2450,9 @@ static int kmem_cache_open(struct kmem_c
if (!init_kmem_cache_nodes(s))
goto error;
+ s->queue = initial_queue_size(s->size);
+ s->batch = (s->queue + 1) / 2;
+
if (alloc_kmem_cache_cpus(s))
return 1;
@@ -2460,8 +2563,9 @@ static inline int kmem_cache_close(struc
{
int node;
+ down_read(&slub_lock);
flush_all(s);
- free_percpu(s->cpu_slab);
+ free_percpu(s->cpu);
/* Attempt to free all objects */
for_each_node_state(node, N_NORMAL_MEMORY) {
struct kmem_cache_node *n = get_node(s, node);
@@ -2471,6 +2575,7 @@ static inline int kmem_cache_close(struc
return 1;
}
free_kmem_cache_nodes(s);
+ up_read(&slub_lock);
return 0;
}
@@ -3110,6 +3215,7 @@ void __init kmem_cache_init(void)
caches++;
}
+ /* Now the kmalloc array is fully functional (*not* the dma array) */
slab_state = UP;
/* Provide the correct kmalloc names now that the caches are up */
@@ -3284,7 +3390,7 @@ static int __cpuinit slab_cpuup_callback
down_read(&slub_lock);
list_for_each_entry(s, &slab_caches, list) {
local_irq_save(flags);
- flush_cpu_objects(s, per_cpu_ptr(s->cpu_slab ,cpu));
+ flush_cpu_objects(s, per_cpu_ptr(s->cpu, cpu));
local_irq_restore(flags);
}
up_read(&slub_lock);
@@ -3751,6 +3857,7 @@ static ssize_t show_slab_objects(struct
return -ENOMEM;
per_cpu = nodes + nr_node_ids;
+ down_read(&slub_lock);
if (flags & SO_ALL) {
for_each_node_state(node, N_NORMAL_MEMORY) {
struct kmem_cache_node *n = get_node(s, node);
@@ -3781,6 +3888,7 @@ static ssize_t show_slab_objects(struct
nodes[node] += x;
}
}
+
x = sprintf(buf, "%lu", total);
#ifdef CONFIG_NUMA
for_each_node_state(node, N_NORMAL_MEMORY)
@@ -3788,6 +3896,7 @@ static ssize_t show_slab_objects(struct
x += sprintf(buf + x, " N%d=%lu",
node, nodes[node]);
#endif
+ up_read(&slub_lock);
kfree(nodes);
return x + sprintf(buf + x, "\n");
}
@@ -3891,6 +4000,57 @@ static ssize_t min_partial_store(struct
}
SLAB_ATTR(min_partial);
+static ssize_t cpu_queue_size_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%u\n", s->queue);
+}
+
+static ssize_t cpu_queue_size_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ unsigned long queue;
+ int err;
+
+ err = strict_strtoul(buf, 10, &queue);
+ if (err)
+ return err;
+
+ if (queue > 10000 || queue < 4)
+ return -EINVAL;
+
+ if (s->batch > queue)
+ s->batch = queue;
+
+ down_write(&slub_lock);
+ resize_cpu_queue(s, queue);
+ up_write(&slub_lock);
+ return length;
+}
+SLAB_ATTR(cpu_queue_size);
+
+static ssize_t cpu_batch_size_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%u\n", s->batch);
+}
+
+static ssize_t cpu_batch_size_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ unsigned long batch;
+ int err;
+
+ err = strict_strtoul(buf, 10, &batch);
+ if (err)
+ return err;
+
+ if (batch < s->queue || batch < 4)
+ return -EINVAL;
+
+ s->batch = batch;
+ return length;
+}
+SLAB_ATTR(cpu_batch_size);
+
static ssize_t ctor_show(struct kmem_cache *s, char *buf)
{
if (s->ctor) {
@@ -3931,8 +4091,9 @@ static ssize_t cpu_queues_show(struct km
if (!cpus)
return -ENOMEM;
+ down_read(&slub_lock);
for_each_online_cpu(cpu) {
- struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu, cpu);
total += c->q.objects;
}
@@ -3940,11 +4101,12 @@ static ssize_t cpu_queues_show(struct km
x = sprintf(buf, "%lu", total);
for_each_online_cpu(cpu) {
- struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu, cpu);
+ struct kmem_cache_queue *q = &c->q;
- if (c->q.objects)
- x += sprintf(buf + x, " C%d=%u", cpu, c->q.objects);
+ x += sprintf(buf + x, " C%d=%u/%u", cpu, q->objects, q->max);
}
+ up_read(&slub_lock);
kfree(cpus);
return x + sprintf(buf + x, "\n");
}
@@ -4196,12 +4358,14 @@ static int show_stat(struct kmem_cache *
if (!data)
return -ENOMEM;
+ down_read(&slub_lock);
for_each_online_cpu(cpu) {
- unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
+ unsigned x = per_cpu_ptr(s->cpu, cpu)->stat[si];
data[cpu] = x;
sum += x;
}
+ up_read(&slub_lock);
len = sprintf(buf, "%lu", sum);
@@ -4219,8 +4383,10 @@ static void clear_stat(struct kmem_cache
{
int cpu;
+ down_write(&slub_lock);
for_each_online_cpu(cpu)
- per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
+ per_cpu_ptr(s->cpu, cpu)->stat[si] = 0;
+ up_write(&slub_lock);
}
#define STAT_ATTR(si, text) \
@@ -4257,6 +4423,8 @@ static struct attribute *slab_attrs[] =
&objs_per_slab_attr.attr,
&order_attr.attr,
&min_partial_attr.attr,
+ &cpu_queue_size_attr.attr,
+ &cpu_batch_size_attr.attr,
&objects_attr.attr,
&objects_partial_attr.attr,
&total_objects_attr.attr,
@@ -4618,7 +4786,7 @@ static int s_show(struct seq_file *m, vo
seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
nr_objs, s->size, oo_objects(s->oo),
(1 << oo_order(s->oo)));
- seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
+ seq_printf(m, " : tunables %4u %4u %4u", s->queue, s->batch, 0);
seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
0UL);
seq_putc(m, '\n');
Index: linux-2.6/include/linux/slub_def.h
===================================================================
--- linux-2.6.orig/include/linux/slub_def.h 2010-08-19 16:34:15.000000000 -0500
+++ linux-2.6/include/linux/slub_def.h 2010-08-19 16:34:20.000000000 -0500
@@ -30,14 +30,11 @@ enum stat_item {
ORDER_FALLBACK, /* Number of times fallback was necessary */
NR_SLUB_STAT_ITEMS };
-#define QUEUE_SIZE 50
-#define BATCH_SIZE 25
-
/* Queueing structure used for per cpu, l3 cache and alien queueing */
struct kmem_cache_queue {
int objects; /* Available objects */
int max; /* Queue capacity */
- void *object[QUEUE_SIZE];
+ void *object[];
};
struct kmem_cache_cpu {
@@ -72,7 +69,7 @@ struct kmem_cache_order_objects {
* Slab cache management.
*/
struct kmem_cache {
- struct kmem_cache_cpu *cpu_slab;
+ struct kmem_cache_cpu *cpu;
/* Used for retriving partial slabs etc */
unsigned long flags;
int size; /* The size of an object including meta data */
@@ -88,6 +85,8 @@ struct kmem_cache {
void (*ctor)(void *);
int inuse; /* Offset to metadata */
int align; /* Alignment */
+ int queue; /* specified queue size */
+ int cpu_queue; /* cpu queue size */
unsigned long min_partial;
const char *name; /* Name (only for display!) */
struct list_head list; /* List of slab caches */
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [S+Q Core 3/6] slub: Get rid of useless function count_free()
2010-08-20 19:01 [S+Q Core 0/6] SLUB: Queueing Core Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 1/6] slub: Add per cpu queueing Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 2/6] slub: Allow resizing of per cpu queues Christoph Lameter
@ 2010-08-20 19:01 ` Christoph Lameter
2010-08-23 17:18 ` Pekka Enberg
2010-08-20 19:01 ` [S+Q Core 4/6] slub: Remove MAX_OBJS limitation Christoph Lameter
` (2 subsequent siblings)
5 siblings, 1 reply; 8+ messages in thread
From: Christoph Lameter @ 2010-08-20 19:01 UTC (permalink / raw)
To: Pekka Enberg; +Cc: linux-mm, David Rientjes
[-- Attachment #1: unified_drop_count_free --]
[-- Type: text/plain, Size: 1749 bytes --]
count_free() == available()
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
mm/slub.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2010-08-19 16:34:20.000000000 -0500
+++ linux-2.6/mm/slub.c 2010-08-19 16:34:23.000000000 -0500
@@ -1692,11 +1692,6 @@ static inline int node_match(struct kmem
return 1;
}
-static int count_free(struct page *page)
-{
- return available(page);
-}
-
static unsigned long count_partial(struct kmem_cache_node *n,
int (*get_count)(struct page *))
{
@@ -1745,7 +1740,7 @@ slab_out_of_memory(struct kmem_cache *s,
if (!n)
continue;
- nr_free = count_partial(n, count_free);
+ nr_free = count_partial(n, available);
nr_slabs = node_nr_slabs(n);
nr_objs = node_nr_objs(n);
@@ -3866,7 +3861,7 @@ static ssize_t show_slab_objects(struct
x = atomic_long_read(&n->total_objects);
else if (flags & SO_OBJECTS)
x = atomic_long_read(&n->total_objects) -
- count_partial(n, count_free);
+ count_partial(n, available);
else
x = atomic_long_read(&n->nr_slabs);
@@ -4778,7 +4773,7 @@ static int s_show(struct seq_file *m, vo
nr_partials += n->nr_partial;
nr_slabs += atomic_long_read(&n->nr_slabs);
nr_objs += atomic_long_read(&n->total_objects);
- nr_free += count_partial(n, count_free);
+ nr_free += count_partial(n, available);
}
nr_inuse = nr_objs - nr_free;
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [S+Q Core 4/6] slub: Remove MAX_OBJS limitation
2010-08-20 19:01 [S+Q Core 0/6] SLUB: Queueing Core Christoph Lameter
` (2 preceding siblings ...)
2010-08-20 19:01 ` [S+Q Core 3/6] slub: Get rid of useless function count_free() Christoph Lameter
@ 2010-08-20 19:01 ` Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 5/6] slub: Drop allocator announcement Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 6/6] slub: Object based NUMA policies Christoph Lameter
5 siblings, 0 replies; 8+ messages in thread
From: Christoph Lameter @ 2010-08-20 19:01 UTC (permalink / raw)
To: Pekka Enberg; +Cc: linux-mm, David Rientjes
[-- Attachment #1: unified_unlimited --]
[-- Type: text/plain, Size: 2267 bytes --]
There is no need anymore for the "inuse" field in the page struct.
Extend the objects field to 32 bit allowing a practically unlimited
number of objects.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
include/linux/mm_types.h | 5 +----
mm/slub.c | 7 -------
2 files changed, 1 insertion(+), 11 deletions(-)
Index: linux-2.6/include/linux/mm_types.h
===================================================================
--- linux-2.6.orig/include/linux/mm_types.h 2010-08-19 16:31:50.000000000 -0500
+++ linux-2.6/include/linux/mm_types.h 2010-08-19 16:34:26.000000000 -0500
@@ -40,10 +40,7 @@ struct page {
* to show when page is mapped
* & limit reverse map searches.
*/
- struct { /* SLUB */
- u16 inuse;
- u16 objects;
- };
+ u32 objects; /* SLUB */
};
union {
struct {
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2010-08-19 16:34:23.000000000 -0500
+++ linux-2.6/mm/slub.c 2010-08-19 16:34:26.000000000 -0500
@@ -143,7 +143,6 @@ static inline int kmem_cache_debug(struc
#define OO_SHIFT 16
#define OO_MASK ((1 << OO_SHIFT) - 1)
-#define MAX_OBJS_PER_PAGE 65535 /* since page.objects is u16 */
/* Internal SLUB flags */
#define __OBJECT_POISON 0x80000000UL /* Poison object */
@@ -789,9 +788,6 @@ static int verify_slab(struct kmem_cache
max_objects = ((void *)page->freelist - start) / s->size;
}
- if (max_objects > MAX_OBJS_PER_PAGE)
- max_objects = MAX_OBJS_PER_PAGE;
-
if (page->objects != max_objects) {
slab_err(s, page, "Wrong number of objects. Found %d but "
"should be %d", page->objects, max_objects);
@@ -2055,9 +2051,6 @@ static inline int slab_order(int size, i
int rem;
int min_order = slub_min_order;
- if ((PAGE_SIZE << min_order) / size > MAX_OBJS_PER_PAGE)
- return get_order(size * MAX_OBJS_PER_PAGE) - 1;
-
for (order = max(min_order,
fls(min_objects * size - 1) - PAGE_SHIFT);
order <= max_order; order++) {
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [S+Q Core 5/6] slub: Drop allocator announcement
2010-08-20 19:01 [S+Q Core 0/6] SLUB: Queueing Core Christoph Lameter
` (3 preceding siblings ...)
2010-08-20 19:01 ` [S+Q Core 4/6] slub: Remove MAX_OBJS limitation Christoph Lameter
@ 2010-08-20 19:01 ` Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 6/6] slub: Object based NUMA policies Christoph Lameter
5 siblings, 0 replies; 8+ messages in thread
From: Christoph Lameter @ 2010-08-20 19:01 UTC (permalink / raw)
To: Pekka Enberg; +Cc: linux-mm, David Rientjes
[-- Attachment #1: unified_remove_banner --]
[-- Type: text/plain, Size: 1086 bytes --]
People get confused because the output repeats some basic hardware
configuration values. Some of the items listed no
longer have the same relevance in the queued form of SLUB.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
mm/slub.c | 6 ------
1 file changed, 6 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2010-08-19 16:34:26.000000000 -0500
+++ linux-2.6/mm/slub.c 2010-08-19 16:34:28.000000000 -0500
@@ -3232,12 +3232,6 @@ void __init kmem_cache_init(void)
}
}
#endif
- printk(KERN_INFO
- "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
- " CPUs=%d, Nodes=%d\n",
- caches, cache_line_size(),
- slub_min_order, slub_max_order, slub_min_objects,
- nr_cpu_ids, nr_node_ids);
}
void __init kmem_cache_init_late(void)
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [S+Q Core 6/6] slub: Object based NUMA policies
2010-08-20 19:01 [S+Q Core 0/6] SLUB: Queueing Core Christoph Lameter
` (4 preceding siblings ...)
2010-08-20 19:01 ` [S+Q Core 5/6] slub: Drop allocator announcement Christoph Lameter
@ 2010-08-20 19:01 ` Christoph Lameter
5 siblings, 0 replies; 8+ messages in thread
From: Christoph Lameter @ 2010-08-20 19:01 UTC (permalink / raw)
To: Pekka Enberg; +Cc: linux-mm, David Rientjes
[-- Attachment #1: unified_object_based_policies --]
[-- Type: text/plain, Size: 11969 bytes --]
Slub applies policies and cpuset restriction currently only on the page
level. The patch here changes that to apply policies to individual allocations
(like SLAB). This comes with a cost of increased complexiy in the allocator.
The allocation does not build alien queues (later patch) and is a bit
ineffective since a slab has to be taken from the partial lists (via lock
and unlock) and possibly shifted back after taking one object out of it.
Memory policies and cpuset redirection is only applied to slabs marked with
SLAB_MEM_SPREAD (also like SLAB).
Use Lee Schermerhorns new *_mem functionality to always find the nearest
node in case we are on a memoryless node.
Note that the handling of queues is significantly different from SLAB.
SLAB has pure queues that only contain objects from the respective nodes
and therefore has to undergo fallback functions if nodes are exhausted.
The approach here has queues that usually contain objects from the
corresponding NUMA nodes. If nodes are exhausted then objects from
foreign nodes may appear in queues as the page allocator falls back
to other nodes. The foreign objects will be freed back to the
correct queues though so that these conditions are temporary.
The caching effect of the queues will degrade in situations when memory
on nodes is no longer available.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
include/linux/slub_def.h | 24 ++++-
mm/slub.c | 200 +++++++++++++++++------------------------------
2 files changed, 93 insertions(+), 131 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2010-08-20 10:31:43.000000000 -0500
+++ linux-2.6/mm/slub.c 2010-08-20 10:32:36.000000000 -0500
@@ -1140,10 +1140,7 @@ static inline struct page *alloc_slab_pa
flags |= __GFP_NOTRACK;
- if (node == NUMA_NO_NODE)
- return alloc_pages(flags, order);
- else
- return alloc_pages_exact_node(node, flags, order);
+ return alloc_pages_exact_node(node, flags, order);
}
static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
@@ -1360,14 +1357,15 @@ static inline int lock_and_freeze_slab(s
/*
* Try to allocate a partial slab from a specific node.
*/
-static struct page *get_partial_node(struct kmem_cache_node *n)
+static struct page *get_partial(struct kmem_cache *s, int node)
{
struct page *page;
+ struct kmem_cache_node *n = get_node(s, node);
/*
* Racy check. If we mistakenly see no partial slabs then we
* just allocate an empty slab. If we mistakenly try to get a
- * partial slab and there is none available then get_partials()
+ * partial slab and there is none available then get_partial()
* will return NULL.
*/
if (!n || !n->nr_partial)
@@ -1384,76 +1382,6 @@ out:
}
/*
- * Get a page from somewhere. Search in increasing NUMA distances.
- */
-static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
-{
-#ifdef CONFIG_NUMA
- struct zonelist *zonelist;
- struct zoneref *z;
- struct zone *zone;
- enum zone_type high_zoneidx = gfp_zone(flags);
- struct page *page;
-
- /*
- * The defrag ratio allows a configuration of the tradeoffs between
- * inter node defragmentation and node local allocations. A lower
- * defrag_ratio increases the tendency to do local allocations
- * instead of attempting to obtain partial slabs from other nodes.
- *
- * If the defrag_ratio is set to 0 then kmalloc() always
- * returns node local objects. If the ratio is higher then kmalloc()
- * may return off node objects because partial slabs are obtained
- * from other nodes and filled up.
- *
- * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
- * defrag_ratio = 1000) then every (well almost) allocation will
- * first attempt to defrag slab caches on other nodes. This means
- * scanning over all nodes to look for partial slabs which may be
- * expensive if we do it every time we are trying to find a slab
- * with available objects.
- */
- if (!s->remote_node_defrag_ratio ||
- get_cycles() % 1024 > s->remote_node_defrag_ratio)
- return NULL;
-
- get_mems_allowed();
- zonelist = node_zonelist(slab_node(current->mempolicy), flags);
- for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
- struct kmem_cache_node *n;
-
- n = get_node(s, zone_to_nid(zone));
-
- if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
- n->nr_partial > s->min_partial) {
- page = get_partial_node(n);
- if (page) {
- put_mems_allowed();
- return page;
- }
- }
- }
- put_mems_allowed();
-#endif
- return NULL;
-}
-
-/*
- * Get a partial page, lock it and return it.
- */
-static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
-{
- struct page *page;
- int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
-
- page = get_partial_node(get_node(s, searchnode));
- if (page || node != -1)
- return page;
-
- return get_any_partial(s, flags);
-}
-
-/*
* Move the vector of objects back to the slab pages they came from
*/
void drain_objects(struct kmem_cache *s, void **object, int nr)
@@ -1617,6 +1545,7 @@ struct kmem_cache_cpu *alloc_kmem_cache_
struct kmem_cache_cpu *c = per_cpu_ptr(k, cpu);
c->q.max = max;
+ c->node = cpu_to_mem(cpu);
}
s->cpu_queue = max;
@@ -1675,19 +1604,6 @@ static void resize_cpu_queue(struct kmem
free_percpu(f.c);
}
-/*
- * Check if the objects in a per cpu structure fit numa
- * locality expectations.
- */
-static inline int node_match(struct kmem_cache_cpu *c, int node)
-{
-#ifdef CONFIG_NUMA
- if (node != NUMA_NO_NODE && c->node != node)
- return 0;
-#endif
- return 1;
-}
-
static unsigned long count_partial(struct kmem_cache_node *n,
int (*get_count)(struct page *))
{
@@ -1747,6 +1663,27 @@ slab_out_of_memory(struct kmem_cache *s,
}
/*
+ * Determine the final numa node from which the allocation will
+ * be occurring. Allocations can be redirected for slabs marked
+ * with SLAB_MEM_SPREAD by memory policies and cpusets options.
+ */
+static inline int find_numa_node(struct kmem_cache *s,
+ int node, int local_node)
+{
+#ifdef CONFIG_NUMA
+ if (unlikely(s->flags & SLAB_MEM_SPREAD)) {
+ if (node == NUMA_NO_NODE && !in_interrupt()) {
+ if (cpuset_do_slab_mem_spread())
+ return cpuset_mem_spread_node();
+ else if (current->mempolicy)
+ return slab_node(current->mempolicy);
+ }
+ }
+#endif
+ return local_node;
+}
+
+/*
* Retrieve pointers to nr objects from a slab into the object array.
* Slab must be locked.
*/
@@ -1797,6 +1734,41 @@ void to_lists(struct kmem_cache *s, stru
/* Handling of objects from other nodes */
+static void *slab_alloc_node(struct kmem_cache *s, struct kmem_cache_cpu *c,
+ gfp_t gfpflags, int node)
+{
+#ifdef CONFIG_NUMA
+ struct page *page;
+ void *object;
+
+ page = get_partial(s, node);
+ if (!page) {
+ gfpflags &= gfp_allowed_mask;
+
+ if (gfpflags & __GFP_WAIT)
+ local_irq_enable();
+
+ page = new_slab(s, gfpflags, node);
+
+ if (gfpflags & __GFP_WAIT)
+ local_irq_disable();
+
+ if (!page)
+ return NULL;
+
+ slab_lock(page);
+ }
+
+ retrieve_objects(s, page, &object, 1);
+
+ to_lists(s, page, 0);
+ slab_unlock(page);
+ return object;
+#else
+ return NULL;
+#endif
+}
+
static void slab_free_alien(struct kmem_cache *s,
struct kmem_cache_cpu *c, struct page *page, void *object, int node)
{
@@ -1822,18 +1794,25 @@ static void *slab_alloc(struct kmem_cach
redo:
local_irq_save(flags);
c = __this_cpu_ptr(s->cpu);
- q = &c->q;
- if (unlikely(queue_empty(q) || !node_match(c, node))) {
- if (unlikely(!node_match(c, node))) {
- flush_cpu_objects(s, c);
- c->node = node;
+ if (NUMA_BUILD) {
+ node = find_numa_node(s, node, c->node);
+
+ if (unlikely(node != c->node)) {
+ object = slab_alloc_node(s, c, gfpflags, node);
+ if (!object)
+ goto oom;
+ stat(s, ALLOC_REMOTE);
+ goto got_it;
}
+ }
+ q = &c->q;
+ if (unlikely(queue_empty(q))) {
while (q->objects < s->batch) {
struct page *new;
- new = get_partial(s, gfpflags & ~__GFP_ZERO, node);
+ new = get_partial(s, node);
if (unlikely(!new)) {
gfpflags &= gfp_allowed_mask;
@@ -1872,6 +1851,7 @@ redo:
object = queue_get(q);
+got_it:
if (kmem_cache_debug(s)) {
if (!alloc_debug_processing(s, object, addr))
goto redo;
@@ -2432,9 +2412,6 @@ static int kmem_cache_open(struct kmem_c
*/
set_min_partial(s, ilog2(s->size));
s->refcount = 1;
-#ifdef CONFIG_NUMA
- s->remote_node_defrag_ratio = 1000;
-#endif
if (!init_kmem_cache_nodes(s))
goto error;
@@ -4305,30 +4282,6 @@ static ssize_t free_calls_show(struct km
}
SLAB_ATTR_RO(free_calls);
-#ifdef CONFIG_NUMA
-static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
-{
- return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
-}
-
-static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
- const char *buf, size_t length)
-{
- unsigned long ratio;
- int err;
-
- err = strict_strtoul(buf, 10, &ratio);
- if (err)
- return err;
-
- if (ratio <= 100)
- s->remote_node_defrag_ratio = ratio * 10;
-
- return length;
-}
-SLAB_ATTR(remote_node_defrag_ratio);
-#endif
-
#ifdef CONFIG_SLUB_STATS
static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
{
@@ -4431,9 +4384,6 @@ static struct attribute *slab_attrs[] =
#ifdef CONFIG_ZONE_DMA
&cache_dma_attr.attr,
#endif
-#ifdef CONFIG_NUMA
- &remote_node_defrag_ratio_attr.attr,
-#endif
#ifdef CONFIG_SLUB_STATS
&alloc_fastpath_attr.attr,
&alloc_slowpath_attr.attr,
Index: linux-2.6/include/linux/slub_def.h
===================================================================
--- linux-2.6.orig/include/linux/slub_def.h 2010-08-20 10:31:41.000000000 -0500
+++ linux-2.6/include/linux/slub_def.h 2010-08-20 10:31:45.000000000 -0500
@@ -24,13 +24,29 @@ enum stat_item {
FREE_REMOVE_PARTIAL, /* Freeing removed from partial list */
ALLOC_FROM_PARTIAL, /* slab with objects acquired from partial */
ALLOC_SLAB, /* New slab acquired from page allocator */
+ ALLOC_REMOTE, /* Allocation from remote slab */
FREE_ALIEN, /* Free to alien node */
FREE_SLAB, /* Slab freed to the page allocator */
QUEUE_FLUSH, /* Flushing of the per cpu queue */
ORDER_FALLBACK, /* Number of times fallback was necessary */
NR_SLUB_STAT_ITEMS };
-/* Queueing structure used for per cpu, l3 cache and alien queueing */
+/*
+ * Queueing structure used for per cpu, l3 cache and alien queueing.
+ *
+ * Queues contain objects from a particular node.
+ * Per cpu and shared queues from kmem_cache_cpu->node
+ * alien caches from other nodes.
+ *
+ * However, this is not strictly enforced if the page allocator redirects
+ * allocation to other nodes because f.e. there is no memory on the node.
+ * Foreign objects will then be on the queue until memory becomes available
+ * again on the node. Freeing objects always occurs to the correct node.
+ *
+ * Which means that queueing is no longer effective since
+ * objects are freed to the alien caches after having been dequeued from
+ * the per cpu queue.
+ */
struct kmem_cache_queue {
int objects; /* Available objects */
int max; /* Queue capacity */
@@ -41,7 +57,7 @@ struct kmem_cache_cpu {
#ifdef CONFIG_SLUB_STATS
unsigned stat[NR_SLUB_STAT_ITEMS];
#endif
- int node; /* objects only from this numa node */
+ int node; /* The memory node local to the cpu */
struct kmem_cache_queue q;
};
@@ -95,10 +111,6 @@ struct kmem_cache {
#endif
#ifdef CONFIG_NUMA
- /*
- * Defragmentation by allocating from a remote node.
- */
- int remote_node_defrag_ratio;
struct kmem_cache_node *node[MAX_NUMNODES];
#else
/* Avoid an extra cache line for UP */
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [S+Q Core 3/6] slub: Get rid of useless function count_free()
2010-08-20 19:01 ` [S+Q Core 3/6] slub: Get rid of useless function count_free() Christoph Lameter
@ 2010-08-23 17:18 ` Pekka Enberg
0 siblings, 0 replies; 8+ messages in thread
From: Pekka Enberg @ 2010-08-23 17:18 UTC (permalink / raw)
To: Christoph Lameter; +Cc: linux-mm, David Rientjes
On 20.8.2010 22.01, Christoph Lameter wrote:
> count_free() == available()
>
> Signed-off-by: Christoph Lameter<cl@linux-foundation.org>
I think you can squash this to patch one.
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2010-08-23 17:18 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-08-20 19:01 [S+Q Core 0/6] SLUB: Queueing Core Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 1/6] slub: Add per cpu queueing Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 2/6] slub: Allow resizing of per cpu queues Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 3/6] slub: Get rid of useless function count_free() Christoph Lameter
2010-08-23 17:18 ` Pekka Enberg
2010-08-20 19:01 ` [S+Q Core 4/6] slub: Remove MAX_OBJS limitation Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 5/6] slub: Drop allocator announcement Christoph Lameter
2010-08-20 19:01 ` [S+Q Core 6/6] slub: Object based NUMA policies Christoph Lameter
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