From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Rokudo Yan <wu-yan@tcl.com>,
Minchan Kim <minchan@kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 4.14 37/39] zsmalloc: account the number of compacted pages correctly
Date: Fri, 5 Mar 2021 13:22:36 +0100 [thread overview]
Message-ID: <20210305120853.626250068@linuxfoundation.org> (raw)
In-Reply-To: <20210305120851.751937389@linuxfoundation.org>
From: Rokudo Yan <wu-yan@tcl.com>
commit 2395928158059b8f9858365fce7713ce7fef62e4 upstream.
There exists multiple path may do zram compaction concurrently.
1. auto-compaction triggered during memory reclaim
2. userspace utils write zram<id>/compaction node
So, multiple threads may call zs_shrinker_scan/zs_compact concurrently.
But pages_compacted is a per zsmalloc pool variable and modification
of the variable is not serialized(through under class->lock).
There are two issues here:
1. the pages_compacted may not equal to total number of pages
freed(due to concurrently add).
2. zs_shrinker_scan may not return the correct number of pages
freed(issued by current shrinker).
The fix is simple:
1. account the number of pages freed in zs_compact locally.
2. use actomic variable pages_compacted to accumulate total number.
Link: https://lkml.kernel.org/r/20210202122235.26885-1-wu-yan@tcl.com
Fixes: 860c707dca155a56 ("zsmalloc: account the number of compacted pages")
Signed-off-by: Rokudo Yan <wu-yan@tcl.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/zram/zram_drv.c | 2 +-
include/linux/zsmalloc.h | 2 +-
mm/zsmalloc.c | 17 +++++++++++------
3 files changed, 13 insertions(+), 8 deletions(-)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -738,7 +738,7 @@ static ssize_t mm_stat_show(struct devic
zram->limit_pages << PAGE_SHIFT,
max_used << PAGE_SHIFT,
(u64)atomic64_read(&zram->stats.same_pages),
- pool_stats.pages_compacted);
+ atomic_long_read(&pool_stats.pages_compacted));
up_read(&zram->init_lock);
return ret;
--- a/include/linux/zsmalloc.h
+++ b/include/linux/zsmalloc.h
@@ -36,7 +36,7 @@ enum zs_mapmode {
struct zs_pool_stats {
/* How many pages were migrated (freed) */
- unsigned long pages_compacted;
+ atomic_long_t pages_compacted;
};
struct zs_pool;
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -2281,11 +2281,13 @@ static unsigned long zs_can_compact(stru
return obj_wasted * class->pages_per_zspage;
}
-static void __zs_compact(struct zs_pool *pool, struct size_class *class)
+static unsigned long __zs_compact(struct zs_pool *pool,
+ struct size_class *class)
{
struct zs_compact_control cc;
struct zspage *src_zspage;
struct zspage *dst_zspage = NULL;
+ unsigned long pages_freed = 0;
spin_lock(&class->lock);
while ((src_zspage = isolate_zspage(class, true))) {
@@ -2315,7 +2317,7 @@ static void __zs_compact(struct zs_pool
putback_zspage(class, dst_zspage);
if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
free_zspage(pool, class, src_zspage);
- pool->stats.pages_compacted += class->pages_per_zspage;
+ pages_freed += class->pages_per_zspage;
}
spin_unlock(&class->lock);
cond_resched();
@@ -2326,12 +2328,15 @@ static void __zs_compact(struct zs_pool
putback_zspage(class, src_zspage);
spin_unlock(&class->lock);
+
+ return pages_freed;
}
unsigned long zs_compact(struct zs_pool *pool)
{
int i;
struct size_class *class;
+ unsigned long pages_freed = 0;
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
class = pool->size_class[i];
@@ -2339,10 +2344,11 @@ unsigned long zs_compact(struct zs_pool
continue;
if (class->index != i)
continue;
- __zs_compact(pool, class);
+ pages_freed += __zs_compact(pool, class);
}
+ atomic_long_add(pages_freed, &pool->stats.pages_compacted);
- return pool->stats.pages_compacted;
+ return pages_freed;
}
EXPORT_SYMBOL_GPL(zs_compact);
@@ -2359,13 +2365,12 @@ static unsigned long zs_shrinker_scan(st
struct zs_pool *pool = container_of(shrinker, struct zs_pool,
shrinker);
- pages_freed = pool->stats.pages_compacted;
/*
* Compact classes and calculate compaction delta.
* Can run concurrently with a manually triggered
* (by user) compaction.
*/
- pages_freed = zs_compact(pool) - pages_freed;
+ pages_freed = zs_compact(pool);
return pages_freed ? pages_freed : SHRINK_STOP;
}
next prev parent reply other threads:[~2021-03-05 12:40 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-05 12:21 [PATCH 4.14 00/39] 4.14.224-rc1 review Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 01/39] net: usb: qmi_wwan: support ZTE P685M modem Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 02/39] scripts: use pkg-config to locate libcrypto Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 03/39] scripts: set proper OpenSSL include dir also for sign-file Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 04/39] hugetlb: fix update_and_free_page contig page struct assumption Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 05/39] drm/virtio: use kvmalloc for large allocations Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 06/39] virtio/s390: implement virtio-ccw revision 2 correctly Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 07/39] arm64 module: set plt* section addresses to 0x0 Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 08/39] arm64: Avoid redundant type conversions in xchg() and cmpxchg() Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 09/39] arm64: cmpxchg: Use "K" instead of "L" for ll/sc immediate constraint Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 10/39] arm64: Use correct ll/sc atomic constraints Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 11/39] JFS: more checks for invalid superblock Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 12/39] media: mceusb: sanity check for prescaler value Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 13/39] xfs: Fix assert failure in xfs_setattr_size() Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 14/39] smackfs: restrict bytes count in smackfs write functions Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 15/39] net: fix up truesize of cloned skb in skb_prepare_for_shift() Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 16/39] mm/hugetlb.c: fix unnecessary address expansion of pmd sharing Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 17/39] net: bridge: use switchdev for port flags set through sysfs too Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 18/39] dt-bindings: net: btusb: DT fix s/interrupt-name/interrupt-names/ Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 19/39] staging: fwserial: Fix error handling in fwserial_create Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 20/39] x86/reboot: Add Zotac ZBOX CI327 nano PCI reboot quirk Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 21/39] vt/consolemap: do font sum unsigned Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 22/39] wlcore: Fix command execute failure 19 for wl12xx Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 23/39] pktgen: fix misuse of BUG_ON() in pktgen_thread_worker() Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 24/39] ath10k: fix wmi mgmt tx queue full due to race condition Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 25/39] x86/build: Treat R_386_PLT32 relocation as R_386_PC32 Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 26/39] Bluetooth: Fix null pointer dereference in amp_read_loc_assoc_final_data Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 27/39] staging: most: sound: add sanity check for function argument Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 28/39] media: uvcvideo: Allow entities with no pads Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 29/39] f2fs: handle unallocated section and zone on pinned/atgc Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 30/39] parisc: Bump 64-bit IRQ stack size to 64 KB Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 31/39] scsi: iscsi: Restrict sessions and handles to admin capabilities Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 32/39] sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 33/39] scsi: iscsi: Ensure sysfs attributes are limited to PAGE_SIZE Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 34/39] scsi: iscsi: Verify lengths on passthrough PDUs Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 35/39] Xen/gnttab: handle p2m update errors on a per-slot basis Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 36/39] xen-netback: respect gnttab_map_refs()s return value Greg Kroah-Hartman
2021-03-05 12:22 ` Greg Kroah-Hartman [this message]
2021-03-05 12:22 ` [PATCH 4.14 38/39] swap: fix swapfile read/write offset Greg Kroah-Hartman
2021-03-05 12:22 ` [PATCH 4.14 39/39] media: v4l: ioctl: Fix memory leak in video_usercopy Greg Kroah-Hartman
2021-03-06 10:16 ` [PATCH 4.14 00/39] 4.14.224-rc1 review Naresh Kamboju
2021-03-06 16:30 ` Guenter Roeck
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