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authorJesper Dangaard Brouer <brouer@redhat.com>2016-03-15 14:53:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-15 16:55:16 -0700
commite6cdb58d1c8307f66039b04203e378d89938281c (patch)
treef95f4de29bd2538a8e7e4845e7de25503cafd9b3 /mm
parent7b0501dd6b1862a83c5c1c65beadce99014b97a4 (diff)
downloadlinux-e6cdb58d1c8307f66039b04203e378d89938281c.tar.bz2
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')
-rw-r--r--mm/slab.c29
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.