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mm: memcg/slab: synchronize access to kmem_cache dying flag using a spinlock
[ Upstream commit 63b02ef7dc
]
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>
This commit is contained in:
parent
91404e91eb
commit
763b04c6b2
1 changed files with 12 additions and 3 deletions
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@ -130,6 +130,7 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
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#ifdef CONFIG_MEMCG_KMEM
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LIST_HEAD(slab_root_caches);
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static DEFINE_SPINLOCK(memcg_kmem_wq_lock);
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void slab_init_memcg_params(struct kmem_cache *s)
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{
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@ -717,14 +718,22 @@ void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
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WARN_ON_ONCE(s->memcg_params.deact_fn))
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return;
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/*
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* memcg_kmem_wq_lock is used to synchronize memcg_params.dying
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* flag and make sure that no new kmem_cache deactivation tasks
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* are queued (see flush_memcg_workqueue() ).
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*/
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spin_lock_irq(&memcg_kmem_wq_lock);
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if (s->memcg_params.root_cache->memcg_params.dying)
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return;
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goto unlock;
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/* pin memcg so that @s doesn't get destroyed in the middle */
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css_get(&s->memcg_params.memcg->css);
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s->memcg_params.deact_fn = deact_fn;
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call_rcu_sched(&s->memcg_params.deact_rcu_head, kmemcg_deactivate_rcufn);
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unlock:
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spin_unlock_irq(&memcg_kmem_wq_lock);
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}
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void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg)
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@ -834,9 +843,9 @@ static int shutdown_memcg_caches(struct kmem_cache *s)
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static void flush_memcg_workqueue(struct kmem_cache *s)
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{
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mutex_lock(&slab_mutex);
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spin_lock_irq(&memcg_kmem_wq_lock);
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s->memcg_params.dying = true;
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mutex_unlock(&slab_mutex);
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spin_unlock_irq(&memcg_kmem_wq_lock);
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/*
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* SLUB deactivates the kmem_caches through call_rcu_sched. Make
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