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| author | Roman Gushchin <guro@fb.com> | 2019-07-11 20:56:24 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-29 10:16:57 +0200 |
| commit | 763b04c6b26bc12c2df36390210e5377b241a8a8 (patch) | |
| tree | b4eed9aeb00eba0c6f039d4bb982c593abe3495d /mm | |
| parent | 91404e91eb85fdb8b6d5d6c01a53cbc63b057e10 (diff) | |
| download | linux-stable-763b04c6b26bc12c2df36390210e5377b241a8a8.tar.gz linux-stable-763b04c6b26bc12c2df36390210e5377b241a8a8.tar.bz2 linux-stable-763b04c6b26bc12c2df36390210e5377b241a8a8.zip | |
mm: memcg/slab: synchronize access to kmem_cache dying flag using a spinlock
[ Upstream commit 63b02ef7dc4ec239df45c018ac0adbd02ba30a0c ]
Currently the memcg_params.dying flag and the corresponding workqueue used
for the asynchronous deactivation of kmem_caches is synchronized using the
slab_mutex.
It makes impossible to check this flag from the irq context, which will be
required in order to implement asynchronous release of kmem_caches.
So let's switch over to the irq-save flavor of the spinlock-based
synchronization.
Link: http://lkml.kernel.org/r/20190611231813.3148843-8-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slab_common.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index b5776b1301f0..3dbf693527dd 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -130,6 +130,7 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr, #ifdef CONFIG_MEMCG_KMEM LIST_HEAD(slab_root_caches); +static DEFINE_SPINLOCK(memcg_kmem_wq_lock); void slab_init_memcg_params(struct kmem_cache *s) { @@ -717,14 +718,22 @@ void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s, WARN_ON_ONCE(s->memcg_params.deact_fn)) return; + /* + * memcg_kmem_wq_lock is used to synchronize memcg_params.dying + * flag and make sure that no new kmem_cache deactivation tasks + * are queued (see flush_memcg_workqueue() ). + */ + spin_lock_irq(&memcg_kmem_wq_lock); if (s->memcg_params.root_cache->memcg_params.dying) - return; + goto unlock; /* pin memcg so that @s doesn't get destroyed in the middle */ css_get(&s->memcg_params.memcg->css); s->memcg_params.deact_fn = deact_fn; call_rcu_sched(&s->memcg_params.deact_rcu_head, kmemcg_deactivate_rcufn); +unlock: + spin_unlock_irq(&memcg_kmem_wq_lock); } void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) @@ -834,9 +843,9 @@ static int shutdown_memcg_caches(struct kmem_cache *s) static void flush_memcg_workqueue(struct kmem_cache *s) { - mutex_lock(&slab_mutex); + spin_lock_irq(&memcg_kmem_wq_lock); s->memcg_params.dying = true; - mutex_unlock(&slab_mutex); + spin_unlock_irq(&memcg_kmem_wq_lock); /* * SLUB deactivates the kmem_caches through call_rcu_sched. Make |