diff options
| author | Shakeel Butt <shakeel.butt@linux.dev> | 2024-10-26 09:37:07 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-06 20:11:20 -0800 |
| commit | 906c38ff52e95575ddf3281bee531eded3dba150 (patch) | |
| tree | 139ddf5fdb1331dbfbfcfea30435d292cfa7116e | |
| parent | 642c66d84cd4c0506698ae52d0c6fd12d3695c01 (diff) | |
memcg: workingset: remove folio_memcg_rcu usage
The function workingset_activation() is called from folio_mark_accessed()
with the guarantee that the given folio can not be freed under us in
workingset_activation(). In addition, the association of the folio and
its memcg can not be broken here because charge migration is no more.
There is no need to use folio_memcg_rcu. Simply use folio_memcg_charged()
because that is what this function cares about.
[akpm@linux-foundation.org: provide folio_memcg_charged stub for CONFIG_MEMCG=n]
Link: https://lkml.kernel.org/r/20241026163707.2479526-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Suggested-by: Yu Zhao <yuzhao@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/memcontrol.h | 34 | ||||
| -rw-r--r-- | mm/workingset.c | 14 |
2 files changed, 4 insertions, 44 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index bb49e0d4b377..8e4608be811d 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -443,35 +443,6 @@ static inline bool folio_memcg_charged(struct folio *folio) return __folio_memcg(folio) != NULL; } -/** - * folio_memcg_rcu - Locklessly get the memory cgroup associated with a folio. - * @folio: Pointer to the folio. - * - * This function assumes that the folio is known to have a - * proper memory cgroup pointer. It's not safe to call this function - * against some type of folios, e.g. slab folios or ex-slab folios. - * - * Return: A pointer to the memory cgroup associated with the folio, - * or NULL. - */ -static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio) -{ - unsigned long memcg_data = READ_ONCE(folio->memcg_data); - - VM_BUG_ON_FOLIO(folio_test_slab(folio), folio); - - if (memcg_data & MEMCG_DATA_KMEM) { - struct obj_cgroup *objcg; - - objcg = (void *)(memcg_data & ~OBJEXTS_FLAGS_MASK); - return obj_cgroup_memcg(objcg); - } - - WARN_ON_ONCE(!rcu_read_lock_held()); - - return (struct mem_cgroup *)(memcg_data & ~OBJEXTS_FLAGS_MASK); -} - /* * folio_memcg_check - Get the memory cgroup associated with a folio. * @folio: Pointer to the folio. @@ -1084,10 +1055,9 @@ static inline struct mem_cgroup *folio_memcg(struct folio *folio) return NULL; } -static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio) +static inline bool folio_memcg_charged(struct folio *folio) { - WARN_ON_ONCE(!rcu_read_lock_held()); - return NULL; + return false; } static inline struct mem_cgroup *folio_memcg_check(struct folio *folio) diff --git a/mm/workingset.c b/mm/workingset.c index a2b28e356e68..0e38bec261a4 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -591,22 +591,12 @@ void workingset_refault(struct folio *folio, void *shadow) */ void workingset_activation(struct folio *folio) { - struct mem_cgroup *memcg; - - rcu_read_lock(); /* * Filter non-memcg pages here, e.g. unmap can call * mark_page_accessed() on VDSO pages. - * - * XXX: See workingset_refault() - this should return - * root_mem_cgroup even for !CONFIG_MEMCG. */ - memcg = folio_memcg_rcu(folio); - if (!mem_cgroup_disabled() && !memcg) - goto out; - workingset_age_nonresident(folio_lruvec(folio), folio_nr_pages(folio)); -out: - rcu_read_unlock(); + if (mem_cgroup_disabled() || folio_memcg_charged(folio)) + workingset_age_nonresident(folio_lruvec(folio), folio_nr_pages(folio)); } /* |