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mm: memcg/slab: generalize postponed non-root kmem_cache deactivation 

Currently SLUB uses a work scheduled after an RCU grace period to
deactivate a non-root kmem_cache.  This mechanism can be reused for
kmem_caches release, but requires generalization for SLAB case.

Introduce kmemcg_cache_deactivate() function, which calls
allocator-specific __kmem_cache_deactivate() and schedules execution of
__kmem_cache_deactivate_after_rcu() with all necessary locks in a worker
context after an rcu grace period.

Here is the new calling scheme:
  kmemcg_cache_deactivate()
    __kmemcg_cache_deactivate()                  SLAB/SLUB-specific
    kmemcg_rcufn()                               rcu
      kmemcg_workfn()                            work
        __kmemcg_cache_deactivate_after_rcu()    SLAB/SLUB-specific

instead of:
  __kmemcg_cache_deactivate()                    SLAB/SLUB-specific
    slab_deactivate_memcg_cache_rcu_sched()      SLUB-only
      kmemcg_rcufn()                             rcu
        kmemcg_workfn()                          work
          kmemcg_cache_deact_after_rcu()         SLUB-only

For consistency, all allocator-specific functions start with "__".

Link: http://lkml.kernel.org/r/20190611231813.3148843-4-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>
This commit is contained in:
Roman Gushchin 2019-07-11 20:56:09 -07:00 committed by Linus Torvalds
parent 0b14e8aa68
commit 4348669475
4 changed files with 14 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
mm/slab.c
View File

@ -2252,6 +2252,10 @@ void __kmemcg_cache_deactivate(struct kmem_cache *cachep)
{
__kmem_cache_shrink(cachep);
}
void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s)
{
}
#endif
int __kmem_cache_shutdown(struct kmem_cache *cachep)

3
mm/slab.h
View File

@ -172,6 +172,7 @@ int __kmem_cache_shutdown(struct kmem_cache *);
void __kmem_cache_release(struct kmem_cache *);
int __kmem_cache_shrink(struct kmem_cache *);
void __kmemcg_cache_deactivate(struct kmem_cache *s);
void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s);
void slab_kmem_cache_release(struct kmem_cache *);
struct seq_file;
@ -290,8 +291,6 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order,
extern void slab_init_memcg_params(struct kmem_cache *);
extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg);
extern void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
void (*work_fn)(struct kmem_cache *));
#else /* CONFIG_MEMCG_KMEM */

27
mm/slab_common.c
View File

@ -708,7 +708,7 @@ static void kmemcg_workfn(struct work_struct *work)
put_online_mems();
put_online_cpus();
/* done, put the ref from slab_deactivate_memcg_cache_rcu_sched() */
/* done, put the ref from kmemcg_cache_deactivate() */
css_put(&s->memcg_params.memcg->css);
}
@ -726,31 +726,21 @@ static void kmemcg_rcufn(struct rcu_head *head)
queue_work(memcg_kmem_cache_wq, &s->memcg_params.work);
}
/**
* slab_deactivate_memcg_cache_rcu_sched - schedule deactivation after a
* sched RCU grace period
* @s: target kmem_cache
* @work_fn: deactivation function to call
*
* Schedule @work_fn to be invoked with online cpus, mems and slab_mutex
* held after a sched RCU grace period. The slab is guaranteed to stay
* alive until @work_fn is finished. This is to be used from
* __kmemcg_cache_deactivate().
*/
void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
void (*work_fn)(struct kmem_cache *))
static void kmemcg_cache_deactivate(struct kmem_cache *s)
{
if (WARN_ON_ONCE(is_root_cache(s)) ||
WARN_ON_ONCE(s->memcg_params.work_fn))
return;
__kmemcg_cache_deactivate(s);
if (s->memcg_params.root_cache->memcg_params.dying)
return;
/* pin memcg so that @s doesn't get destroyed in the middle */
css_get(&s->memcg_params.memcg->css);
s->memcg_params.work_fn = work_fn;
s->memcg_params.work_fn = __kmemcg_cache_deactivate_after_rcu;
call_rcu(&s->memcg_params.rcu_head, kmemcg_rcufn);
}
@ -773,7 +763,7 @@ void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg)
if (!c)
continue;
__kmemcg_cache_deactivate(c);
kmemcg_cache_deactivate(c);
arr->entries[idx] = NULL;
}
mutex_unlock(&slab_mutex);
@ -866,11 +856,10 @@ static void flush_memcg_workqueue(struct kmem_cache *s)
mutex_unlock(&slab_mutex);
/*
* SLUB deactivates the kmem_caches through call_rcu. Make
* SLAB and SLUB deactivate the kmem_caches through call_rcu. Make
* sure all registered rcu callbacks have been invoked.
*/
if (IS_ENABLED(CONFIG_SLUB))
rcu_barrier();
rcu_barrier();
/*
* SLAB and SLUB create memcg kmem_caches through workqueue and SLUB

8
mm/slub.c
View File

@ -4008,7 +4008,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
}
#ifdef CONFIG_MEMCG
static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s)
void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s)
{
/*
* Called with all the locks held after a sched RCU grace period.
@ -4034,12 +4034,6 @@ void __kmemcg_cache_deactivate(struct kmem_cache *s)
*/
slub_set_cpu_partial(s, 0);
s->min_partial = 0;
/*
* s->cpu_partial is checked locklessly (see put_cpu_partial), so
* we have to make sure the change is visible before shrinking.
*/
slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu);
}
#endif /* CONFIG_MEMCG */