The patch titled
Subject: slab: implement bulk free in SLAB allocator
has been added to the -mm tree. Its filename is
slab-implement-bulk-free-in-slab-allocator.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/slab-implement-bulk-free-in-slab-allocator.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/slab-implement-bulk-free-in-slab-allocator.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)
diff -puN mm/slab.c~slab-implement-bulk-free-in-slab-allocator mm/slab.c
--- a/mm/slab.c~slab-implement-bulk-free-in-slab-allocator
+++ a/mm/slab.c
@@ -3383,12 +3383,6 @@ void *kmem_cache_alloc(struct kmem_cache
}
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)
@@ -3582,6 +3576,29 @@ void kmem_cache_free(struct kmem_cache *
}
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.
_
Patches currently in -mm which might be from brouer@xxxxxxxxxx are
slub-cleanup-code-for-kmem-cgroup-support-to-kmem_cache_free_bulk.patch
mm-slab-move-slub-alloc-hooks-to-common-mm-slabh.patch
mm-fault-inject-take-over-bootstrap-kmem_cache-check.patch
slab-use-slab_pre_alloc_hook-in-slab-allocator-shared-with-slub.patch
mm-kmemcheck-skip-object-if-slab-allocation-failed.patch
slab-use-slab_post_alloc_hook-in-slab-allocator-shared-with-slub.patch
slab-implement-bulk-alloc-in-slab-allocator.patch
slab-avoid-running-debug-slab-code-with-irqs-disabled-for-alloc_bulk.patch
slab-implement-bulk-free-in-slab-allocator.patch
mm-new-api-kfree_bulk-for-slabslub-allocators.patch
mm-fix-some-spelling.patch
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