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authorMuchun Song <songmuchun@bytedance.com>2022-04-29 20:30:44 +0800
committerVlastimil Babka <vbabka@suse.cz>2022-07-04 17:13:05 +0200
commitb77d5b1b83e3e14870224de7c63f115a2dc44e9a (patch)
tree4c9ad0b977e29f88a0867df5002db0a1e938821c /mm/slab.h
parentb347aa7b57477f71c740e2bbc6d1078a7109ba23 (diff)
mm: slab: optimize memcg_slab_free_hook()
Most callers of memcg_slab_free_hook() already know the slab, which could be passed to memcg_slab_free_hook() directly to reduce the overhead of an another call of virt_to_slab(). For bulk freeing of objects, the call of slab_objcgs() in the loop in memcg_slab_free_hook() is redundant as well. Rework memcg_slab_free_hook() and build_detached_freelist() to reduce those unnecessary overhead and make memcg_slab_free_hook() can handle bulk freeing in slab_free(). Move the calling site of memcg_slab_free_hook() from do_slab_free() to slab_free() for slub to make the code clearer since the logic is weird (e.g. the caller need to judge whether it needs to call memcg_slab_free_hook()). It is easy to make mistakes like missing calling of memcg_slab_free_hook() like fixes of: commit d1b2cf6cb84a ("mm: memcg/slab: uncharge during kmem_cache_free_bulk()") commit ae085d7f9365 ("mm: kfence: fix missing objcg housekeeping for SLAB") This optimization is mainly for bulk objects freeing. The following numbers is shown for 16-object freeing. before after kmem_cache_free_bulk: ~430 ns ~400 ns The overhead is reduced by about 7% for 16-object freeing. Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Link: https://lore.kernel.org/r/20220429123044.37885-1-songmuchun@bytedance.com Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Diffstat (limited to 'mm/slab.h')
-rw-r--r--mm/slab.h30
1 files changed, 8 insertions, 22 deletions
diff --git a/mm/slab.h b/mm/slab.h
index db9fb5c8dae7..a8d5eb1c323f 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -547,36 +547,22 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
obj_cgroup_put(objcg);
}
-static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
+static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
void **p, int objects)
{
- struct kmem_cache *s;
struct obj_cgroup **objcgs;
- struct obj_cgroup *objcg;
- struct slab *slab;
- unsigned int off;
int i;
if (!memcg_kmem_enabled())
return;
- for (i = 0; i < objects; i++) {
- if (unlikely(!p[i]))
- continue;
-
- slab = virt_to_slab(p[i]);
- /* we could be given a kmalloc_large() object, skip those */
- if (!slab)
- continue;
-
- objcgs = slab_objcgs(slab);
- if (!objcgs)
- continue;
+ objcgs = slab_objcgs(slab);
+ if (!objcgs)
+ return;
- if (!s_orig)
- s = slab->slab_cache;
- else
- s = s_orig;
+ for (i = 0; i < objects; i++) {
+ struct obj_cgroup *objcg;
+ unsigned int off;
off = obj_to_index(s, slab, p[i]);
objcg = objcgs[off];
@@ -628,7 +614,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
{
}
-static inline void memcg_slab_free_hook(struct kmem_cache *s,
+static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
void **p, int objects)
{
}