From 9855609bde03e2472b99a95e869d29ee1e78a751 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 6 Aug 2020 23:21:10 -0700 Subject: mm: memcg/slab: use a single set of kmem_caches for all accounted allocations This is fairly big but mostly red patch, which makes all accounted slab allocations use a single set of kmem_caches instead of creating a separate set for each memory cgroup. Because the number of non-root kmem_caches is now capped by the number of root kmem_caches, there is no need to shrink or destroy them prematurely. They can be perfectly destroyed together with their root counterparts. This allows to dramatically simplify the management of non-root kmem_caches and delete a ton of code. This patch performs the following changes: 1) introduces memcg_params.memcg_cache pointer to represent the kmem_cache which will be used for all non-root allocations 2) reuses the existing memcg kmem_cache creation mechanism to create memcg kmem_cache on the first allocation attempt 3) memcg kmem_caches are named -memcg, e.g. dentry-memcg 4) simplifies memcg_kmem_get_cache() to just return memcg kmem_cache or schedule it's creation and return the root cache 5) removes almost all non-root kmem_cache management code (separate refcounter, reparenting, shrinking, etc) 6) makes slab debugfs to display root_mem_cgroup css id and never show :dead and :deact flags in the memcg_slabinfo attribute. Following patches in the series will simplify the kmem_cache creation. Signed-off-by: Roman Gushchin Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Shakeel Butt Cc: Christoph Lameter Cc: Johannes Weiner Cc: Michal Hocko Cc: Tejun Heo Link: http://lkml.kernel.org/r/20200623174037.3951353-13-guro@fb.com Signed-off-by: Linus Torvalds --- mm/slub.c | 38 +++++--------------------------------- 1 file changed, 5 insertions(+), 33 deletions(-) (limited to 'mm/slub.c') diff --git a/mm/slub.c b/mm/slub.c index 47e63b1100d4..44a48a08a691 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -4204,36 +4204,6 @@ int __kmem_cache_shrink(struct kmem_cache *s) return ret; } -#ifdef CONFIG_MEMCG -void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s) -{ - /* - * Called with all the locks held after a sched RCU grace period. - * Even if @s becomes empty after shrinking, we can't know that @s - * doesn't have allocations already in-flight and thus can't - * destroy @s until the associated memcg is released. - * - * However, let's remove the sysfs files for empty caches here. - * Each cache has a lot of interface files which aren't - * particularly useful for empty draining caches; otherwise, we can - * easily end up with millions of unnecessary sysfs files on - * systems which have a lot of memory and transient cgroups. - */ - if (!__kmem_cache_shrink(s)) - sysfs_slab_remove(s); -} - -void __kmemcg_cache_deactivate(struct kmem_cache *s) -{ - /* - * Disable empty slabs caching. Used to avoid pinning offline - * memory cgroups by kmem pages that can be freed. - */ - slub_set_cpu_partial(s, 0); - s->min_partial = 0; -} -#endif /* CONFIG_MEMCG */ - static int slab_mem_going_offline_callback(void *arg) { struct kmem_cache *s; @@ -4390,7 +4360,7 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache) } slab_init_memcg_params(s); list_add(&s->list, &slab_caches); - memcg_link_cache(s, NULL); + memcg_link_cache(s); return s; } @@ -4458,7 +4428,8 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align, s->object_size = max(s->object_size, size); s->inuse = max(s->inuse, ALIGN(size, sizeof(void *))); - for_each_memcg_cache(c, s) { + c = memcg_cache(s); + if (c) { c->object_size = s->object_size; c->inuse = max(c->inuse, ALIGN(size, sizeof(void *))); } @@ -5591,7 +5562,8 @@ static ssize_t slab_attr_store(struct kobject *kobj, * directly either failed or succeeded, in which case we loop * through the descendants with best-effort propagation. */ - for_each_memcg_cache(c, s) + c = memcg_cache(s); + if (c) attribute->store(c, buf, len); mutex_unlock(&slab_mutex); } -- cgit v1.2.3