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| author | Muchun Song <songmuchun@bytedance.com> | 2022-04-29 14:30:44 +0200 |
|---|---|---|
| committer | Vlastimil Babka <vbabka@suse.cz> | 2022-07-04 17:13:05 +0200 |
| commit | b77d5b1b83e3e14870224de7c63f115a2dc44e9a (patch) | |
| tree | 4c9ad0b977e29f88a0867df5002db0a1e938821c /mm/slab.c | |
| parent | mm/tracing: add 'accounted' entry into output of allocation tracepoints (diff) | |
| download | linux-b77d5b1b83e3e14870224de7c63f115a2dc44e9a.tar.xz 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.c')
| -rw-r--r-- | mm/slab.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/slab.c b/mm/slab.c index f7d6ca702018..764cbadba69c 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3406,9 +3406,10 @@ static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, { bool init; + memcg_slab_free_hook(cachep, virt_to_slab(objp), &objp, 1); + if (is_kfence_address(objp)) { kmemleak_free_recursive(objp, cachep->flags); - memcg_slab_free_hook(cachep, &objp, 1); __kfence_free(objp); return; } @@ -3441,7 +3442,6 @@ void ___cache_free(struct kmem_cache *cachep, void *objp, check_irq_off(); kmemleak_free_recursive(objp, cachep->flags); objp = cache_free_debugcheck(cachep, objp, caller); - memcg_slab_free_hook(cachep, &objp, 1); /* * Skip calling cache_free_alien() when the platform is not numa. |