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authorYang Shi <shy828301@gmail.com>2021-05-04 18:36:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-05 11:27:23 -0700
commit468ab8437a97a953895856c3709e48b3067da13c (patch)
tree9825960fa4bd466f567148ca655b354e344f191d /mm/vmscan.c
parente4262c4f51d6373447c9d89093f49ff6b1e607be (diff)
mm: vmscan: add shrinker_info_protected() helper
The shrinker_info is dereferenced in a couple of places via rcu_dereference_protected with different calling conventions, for example, using mem_cgroup_nodeinfo helper or dereferencing memcg->nodeinfo[nid]->shrinker_info. And the later patch will add more dereference places. So extract the dereference into a helper to make the code more readable. No functional change. [akpm@linux-foundation.org: retain rcu_dereference_protected() in free_shrinker_info(), per Hugh] Link: https://lkml.kernel.org/r/20210311190845.9708-8-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> 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>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 518084ce8757..400f4a657b27 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -192,6 +192,13 @@ static inline int shrinker_map_size(int nr_items)
return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long));
}
+static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
+ int nid)
+{
+ return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
+ lockdep_is_held(&shrinker_rwsem));
+}
+
static int expand_one_shrinker_info(struct mem_cgroup *memcg,
int size, int old_size)
{
@@ -201,7 +208,7 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg,
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
- old = rcu_dereference_protected(pn->shrinker_info, true);
+ old = shrinker_info_protected(memcg, nid);
/* Not yet online memcg */
if (!old)
return 0;
@@ -675,8 +682,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
if (!down_read_trylock(&shrinker_rwsem))
return 0;
- info = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
- true);
+ info = shrinker_info_protected(memcg, nid);
if (unlikely(!info))
goto unlock;