diff options
| author |   Jesper Dangaard Brouer <brouer@redhat.com> | 2016-03-15 14:53:56 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-15 16:55:16 -0700 |
| commit | e6cdb58d1c8307f66039b04203e378d89938281c (patch) | |
| tree | f95f4de29bd2538a8e7e4845e7de25503cafd9b3 /mm/slab.c | |
| parent | slab: avoid running debug SLAB code with IRQs disabled for alloc_bulk (diff) | |
| download | linux-dev-e6cdb58d1c8307f66039b04203e378d89938281c.tar.xz linux-dev-e6cdb58d1c8307f66039b04203e378d89938281c.zip | |
slab: implement bulk free in SLAB allocator
This patch implements the free side of bulk API for the SLAB allocator
kmem_cache_free_bulk(), and concludes the implementation of optimized
bulk API for SLAB allocator.
Benchmarked[1] cost of alloc+free (obj size 256 bytes) on CPU i7-4790K @
4.00GHz, with no debug options, no PREEMPT and CONFIG_MEMCG_KMEM=y but
no active user of kmemcg.
SLAB single alloc+free cost: 87 cycles(tsc) 21.814 ns with this
optimized config.
bulk- Current fallback - optimized SLAB bulk
1 - 102 cycles(tsc) 25.747 ns - 41 cycles(tsc) 10.490 ns - improved 59.8%
2 - 94 cycles(tsc) 23.546 ns - 26 cycles(tsc) 6.567 ns - improved 72.3%
3 - 92 cycles(tsc) 23.127 ns - 20 cycles(tsc) 5.244 ns - improved 78.3%
4 - 90 cycles(tsc) 22.663 ns - 18 cycles(tsc) 4.588 ns - improved 80.0%
8 - 88 cycles(tsc) 22.242 ns - 14 cycles(tsc) 3.656 ns - improved 84.1%
16 - 88 cycles(tsc) 22.010 ns - 13 cycles(tsc) 3.480 ns - improved 85.2%
30 - 89 cycles(tsc) 22.305 ns - 13 cycles(tsc) 3.303 ns - improved 85.4%
32 - 89 cycles(tsc) 22.277 ns - 13 cycles(tsc) 3.309 ns - improved 85.4%
34 - 88 cycles(tsc) 22.246 ns - 13 cycles(tsc) 3.294 ns - improved 85.2%
48 - 88 cycles(tsc) 22.121 ns - 13 cycles(tsc) 3.492 ns - improved 85.2%
64 - 88 cycles(tsc) 22.052 ns - 13 cycles(tsc) 3.411 ns - improved 85.2%
128 - 89 cycles(tsc) 22.452 ns - 15 cycles(tsc) 3.841 ns - improved 83.1%
158 - 89 cycles(tsc) 22.403 ns - 14 cycles(tsc) 3.746 ns - improved 84.3%
250 - 91 cycles(tsc) 22.775 ns - 16 cycles(tsc) 4.111 ns - improved 82.4%
Notice it is not recommended to do very large bulk operation with
this bulk API, because local IRQs are disabled in this period.
[1] https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/slab_bulk_test01.c
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.c')
| -rw-r--r-- | mm/slab.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/mm/slab.c b/mm/slab.c index 207fa92502de..2e075c0acfcf 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3385,12 +3385,6 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) } EXPORT_SYMBOL(kmem_cache_alloc); -void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p) -{ - __kmem_cache_free_bulk(s, size, p); -} -EXPORT_SYMBOL(kmem_cache_free_bulk); - static __always_inline void cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags, size_t size, void **p, unsigned long caller) @@ -3584,6 +3578,29 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp) } EXPORT_SYMBOL(kmem_cache_free); +void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p) +{ + struct kmem_cache *s; + size_t i; + + local_irq_disable(); + for (i = 0; i < size; i++) { + void *objp = p[i]; + + s = cache_from_obj(orig_s, objp); + + debug_check_no_locks_freed(objp, s->object_size); + if (!(s->flags & SLAB_DEBUG_OBJECTS)) + debug_check_no_obj_freed(objp, s->object_size); + + __cache_free(s, objp, _RET_IP_); + } + local_irq_enable(); + + /* FIXME: add tracing */ +} +EXPORT_SYMBOL(kmem_cache_free_bulk); + /** * kfree - free previously allocated memory * @objp: pointer returned by kmalloc. |