mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
![Rokudo Yan](/assets/img/avatar_default.png)
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: 860c707dca
("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>
59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
/*
|
|
* zsmalloc memory allocator
|
|
*
|
|
* Copyright (C) 2011 Nitin Gupta
|
|
* Copyright (C) 2012, 2013 Minchan Kim
|
|
*
|
|
* This code is released using a dual license strategy: BSD/GPL
|
|
* You can choose the license that better fits your requirements.
|
|
*
|
|
* Released under the terms of 3-clause BSD License
|
|
* Released under the terms of GNU General Public License Version 2.0
|
|
*/
|
|
|
|
#ifndef _ZS_MALLOC_H_
|
|
#define _ZS_MALLOC_H_
|
|
|
|
#include <linux/types.h>
|
|
|
|
/*
|
|
* zsmalloc mapping modes
|
|
*
|
|
* NOTE: These only make a difference when a mapped object spans pages.
|
|
*/
|
|
enum zs_mapmode {
|
|
ZS_MM_RW, /* normal read-write mapping */
|
|
ZS_MM_RO, /* read-only (no copy-out at unmap time) */
|
|
ZS_MM_WO /* write-only (no copy-in at map time) */
|
|
/*
|
|
* NOTE: ZS_MM_WO should only be used for initializing new
|
|
* (uninitialized) allocations. Partial writes to already
|
|
* initialized allocations should use ZS_MM_RW to preserve the
|
|
* existing data.
|
|
*/
|
|
};
|
|
|
|
struct zs_pool_stats {
|
|
/* How many pages were migrated (freed) */
|
|
atomic_long_t pages_compacted;
|
|
};
|
|
|
|
struct zs_pool;
|
|
|
|
struct zs_pool *zs_create_pool(const char *name);
|
|
void zs_destroy_pool(struct zs_pool *pool);
|
|
|
|
unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t flags);
|
|
void zs_free(struct zs_pool *pool, unsigned long obj);
|
|
|
|
size_t zs_huge_class_size(struct zs_pool *pool);
|
|
|
|
void *zs_map_object(struct zs_pool *pool, unsigned long handle,
|
|
enum zs_mapmode mm);
|
|
void zs_unmap_object(struct zs_pool *pool, unsigned long handle);
|
|
|
|
unsigned long zs_get_total_pages(struct zs_pool *pool);
|
|
unsigned long zs_compact(struct zs_pool *pool);
|
|
|
|
void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats);
|
|
#endif
|