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author | 2022-04-29 20:30:44 +0800 | |
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committer | 2022-07-04 17:13:05 +0200 | |
commit | b77d5b1b83e3e14870224de7c63f115a2dc44e9a (patch) | |
tree | 4c9ad0b977e29f88a0867df5002db0a1e938821c /mm/slab.h | |
parent | mm/tracing: add 'accounted' entry into output of allocation tracepoints (diff) | |
download | linux-b77d5b1b83e3e14870224de7c63f115a2dc44e9a.tar.gz linux-b77d5b1b83e3e14870224de7c63f115a2dc44e9a.tar.bz2 linux-b77d5b1b83e3e14870224de7c63f115a2dc44e9a.zip |
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.h | 30 |
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) { } |