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Commit b6ecd2de authored by Vladimir Davydov's avatar Vladimir Davydov Committed by Linus Torvalds
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mm: memcontrol: zap memcg_kmem_online helper 



As kmem accounting is now either enabled for all cgroups or disabled
system-wide, there's no point in having memcg_kmem_online() helper -
instead one can use memcg_kmem_enabled() and mem_cgroup_online(), as
shrink_slab() now does.

There are only two places left where this helper is used -
__memcg_kmem_charge() and memcg_create_kmem_cache().  The former can
only be called if memcg_kmem_enabled() returned true.  Since the cgroup
it operates on is online, mem_cgroup_is_root() check will be enough.

memcg_create_kmem_cache() can't use mem_cgroup_online() helper instead
of memcg_kmem_online(), because it relies on the fact that in
memcg_offline_kmem() memcg->kmem_state is changed before
memcg_deactivate_kmem_caches() is called, but there we can just
open-code the check.

Signed-off-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0fc9f58a

include/linux/memcontrol.h

+0 −10
Original line number Diff line number Diff line
@@ -795,11 +795,6 @@ static inline bool memcg_kmem_enabled(void) 
	return static_branch_unlikely(&memcg_kmem_enabled_key);

}



static inline bool memcg_kmem_online(struct mem_cgroup *memcg)

{

	return memcg->kmem_state == KMEM_ONLINE;

}



/*

 * In general, we'll do everything in our power to not incur in any overhead

 * for non-memcg users for the kmem functions. Not even a function call, if we
@@ -909,11 +904,6 @@ static inline bool memcg_kmem_enabled(void) 
	return false;

}



static inline bool memcg_kmem_online(struct mem_cgroup *memcg)

{

	return false;

}



static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)

{

	return 0;

mm/memcontrol.c

+1 −1
Original line number Diff line number Diff line
@@ -2346,7 +2346,7 @@ int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order) 
	int ret = 0;



	memcg = get_mem_cgroup_from_mm(current->mm);

	if (memcg_kmem_online(memcg))

	if (!mem_cgroup_is_root(memcg))

		ret = __memcg_kmem_charge_memcg(page, gfp, order, memcg);

	css_put(&memcg->css);

	return ret;

mm/slab_common.c

+1 −1
Original line number Diff line number Diff line
@@ -510,7 +510,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg, 
	 * The memory cgroup could have been offlined while the cache

	 * creation work was pending.

	 */

	if (!memcg_kmem_online(memcg))

	if (memcg->kmem_state != KMEM_ONLINE)

		goto out_unlock;



	idx = memcg_cache_id(memcg);