The patch titled
Subject: mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers
has been added to the -mm tree. Its filename is
mm-vmscan-dont-need-allocate-shrinker-nr_deferred-for-memcg-aware-shrinkers.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-dont-need-allocate-shrinker-nr_deferred-for-memcg-aware-shrinkers.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-dont-need-allocate-shrinker-nr_deferred-for-memcg-aware-shrinkers.patch
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------------------------------------------------------
From: Yang Shi <shy828301@xxxxxxxxx>
Subject: 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@xxxxxxxxx
Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-dont-need-allocate-shrinker-nr_deferred-for-memcg-aware-shrinkers
+++ a/mm/vmscan.c
@@ -346,6 +346,9 @@ static int prealloc_memcg_shrinker(struc
{
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(st
#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(str
*/
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 *s
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);
_
Patches currently in -mm which might be from shy828301@xxxxxxxxx are
mm-vmscan-use-nid-from-shrink_control-for-tracepoint.patch
mm-vmscan-consolidate-shrinker_maps-handling-code.patch
mm-vmscan-use-shrinker_rwsem-to-protect-shrinker_maps-allocation.patch
mm-vmscan-remove-memcg_shrinker_map_size.patch
mm-vmscan-use-kvfree_rcu-instead-of-call_rcu.patch
mm-memcontrol-rename-shrinker_map-to-shrinker_info.patch
mm-vmscan-add-shrinker_info_protected-helper.patch
mm-vmscan-use-a-new-flag-to-indicate-shrinker-is-registered.patch
mm-vmscan-add-per-memcg-shrinker-nr_deferred.patch
mm-vmscan-use-per-memcg-nr_deferred-of-shrinker.patch
mm-vmscan-dont-need-allocate-shrinker-nr_deferred-for-memcg-aware-shrinkers.patch
mm-memcontrol-reparent-nr_deferred-when-memcg-offline.patch
mm-vmscan-shrink-deferred-objects-proportional-to-priority.patch
