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mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers 

Now nr_deferred is available on per memcg level for memcg aware
shrinkers, so don't need allocate shrinker->nr_deferred for such
shrinkers anymore.

The prealloc_memcg_shrinker() would return -ENOSYS if !CONFIG_MEMCG or
memcg is disabled by kernel command line, then shrinker's
SHRINKER_MEMCG_AWARE flag would be cleared.  This makes the
implementation of this patch simpler.

Link: https://lkml.kernel.org/r/20210311190845.9708-12-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yang Shi 2021-05-04 18:36:39 -07:00 committed by Linus Torvalds
parent 8675083046
commit 476b30a094
1 changed files with 16 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
mm/vmscan.c
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@ -346,6 +346,9 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
{
int id, ret = -ENOMEM;
if (mem_cgroup_disabled())
return -ENOSYS;
down_write(&shrinker_rwsem);
/* This may call shrinker, so it must use down_read_trylock() */
id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL);
@ -425,7 +428,7 @@ static bool writeback_throttling_sane(struct scan_control *sc)
#else
static int prealloc_memcg_shrinker(struct shrinker *shrinker)
{
return 0;
return -ENOSYS;
}
static void unregister_memcg_shrinker(struct shrinker *shrinker)
@ -537,8 +540,18 @@ static unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru,
*/
int prealloc_shrinker(struct shrinker *shrinker)
{
unsigned int size = sizeof(*shrinker->nr_deferred);
unsigned int size;
int err;
if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
err = prealloc_memcg_shrinker(shrinker);
if (err != -ENOSYS)
return err;
shrinker->flags &= ~SHRINKER_MEMCG_AWARE;
}
size = sizeof(*shrinker->nr_deferred);
if (shrinker->flags & SHRINKER_NUMA_AWARE)
size *= nr_node_ids;
@ -546,28 +559,16 @@ int prealloc_shrinker(struct shrinker *shrinker)
if (!shrinker->nr_deferred)
return -ENOMEM;
if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
if (prealloc_memcg_shrinker(shrinker))
goto free_deferred;
}
return 0;
free_deferred:
kfree(shrinker->nr_deferred);
shrinker->nr_deferred = NULL;
return -ENOMEM;
}
void free_prealloced_shrinker(struct shrinker *shrinker)
{
if (!shrinker->nr_deferred)
return;
if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
down_write(&shrinker_rwsem);
unregister_memcg_shrinker(shrinker);
up_write(&shrinker_rwsem);
return;
}
kfree(shrinker->nr_deferred);