The patch titled
Subject: mm/slab: support slab merge
has been added to the -mm tree. Its filename is
mm-slab-support-slab-merge.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slab-support-slab-merge.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab-support-slab-merge.patch
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------------------------------------------------------
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: mm/slab: support slab merge
Slab merge is good feature to reduce fragmentation. If new creating slab
have similar size and property with exsitent slab, this feature reuse it
rather than creating new one. As a result, objects are packed into fewer
slabs so that fragmentation is reduced.
Below is result of my testing.
* After boot, sleep 20; cat /proc/meminfo | grep Slab
<Before>
Slab: 25136 kB
<After>
Slab: 24364 kB
We can save 3% memory used by slab.
For supporting this feature in SLAB, we need to implement SLAB specific
kmem_cache_flag() and __kmem_cache_alias(), because SLUB implements some
SLUB specific processing related to debug flag and object size change on
these functions.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 20 ++++++++++++++++++++
mm/slab.h | 2 +-
2 files changed, 21 insertions(+), 1 deletion(-)
diff -puN mm/slab.c~mm-slab-support-slab-merge mm/slab.c
--- a/mm/slab.c~mm-slab-support-slab-merge
+++ a/mm/slab.c
@@ -2104,6 +2104,26 @@ static int __init_refok setup_cpu_cache(
return 0;
}
+unsigned long kmem_cache_flags(unsigned long object_size,
+ unsigned long flags, const char *name,
+ void (*ctor)(void *))
+{
+ return flags;
+}
+
+struct kmem_cache *
+__kmem_cache_alias(const char *name, size_t size, size_t align,
+ unsigned long flags, void (*ctor)(void *))
+{
+ struct kmem_cache *cachep;
+
+ cachep = find_mergeable(size, align, flags, name, ctor);
+ if (cachep)
+ cachep->refcount++;
+
+ return cachep;
+}
+
/**
* __kmem_cache_create - Create a cache.
* @cachep: cache management descriptor
diff -puN mm/slab.h~mm-slab-support-slab-merge mm/slab.h
--- a/mm/slab.h~mm-slab-support-slab-merge
+++ a/mm/slab.h
@@ -92,7 +92,7 @@ struct mem_cgroup;
int slab_unmergeable(struct kmem_cache *s);
struct kmem_cache *find_mergeable(size_t size, size_t align,
unsigned long flags, const char *name, void (*ctor)(void *));
-#ifdef CONFIG_SLUB
+#ifndef CONFIG_SLOB
struct kmem_cache *
__kmem_cache_alias(const char *name, size_t size, size_t align,
unsigned long flags, void (*ctor)(void *));
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
mm-slab_commonc-suppress-warning.patch
mm-slab_common-move-kmem_cache-definition-to-internal-header.patch
mm-slab_common-move-kmem_cache-definition-to-internal-header-fix.patch
mm-slab_common-move-kmem_cache-definition-to-internal-header-fix-2.patch
mm-slab_common-move-kmem_cache-definition-to-internal-header-fix-2-fix.patch
mm-slb-always-track-caller-in-kmalloc_node_track_caller.patch
mm-slab-move-cache_flusharray-out-of-unlikelytext-section.patch
mm-slab-noinline-__ac_put_obj.patch
mm-slab-factor-out-unlikely-part-of-cache_free_alien.patch
slub-disable-tracing-and-failslab-for-merged-slabs.patch
topology-add-support-for-node_to_mem_node-to-determine-the-fallback-node.patch
slub-fallback-to-node_to_mem_node-node-if-allocating-on-memoryless-node.patch
partial-revert-of-81c98869faa5-kthread-ensure-locality-of-task_struct-allocations.patch
slab-fix-for_each_kmem_cache_node.patch
mm-slab_common-commonize-slab-merge-logic.patch
mm-slab-support-slab-merge.patch
mm-slab-use-percpu-allocator-for-cpu-cache.patch
mm-cma-adjust-address-limit-to-avoid-hitting-low-high-memory-boundary.patch
arm-mm-dont-limit-default-cma-region-only-to-low-memory.patch
mm-page_alloc-determine-migratetype-only-once.patch
mm-thp-dont-hold-mmap_sem-in-khugepaged-when-allocating-thp.patch
mm-compaction-defer-each-zone-individually-instead-of-preferred-zone.patch
mm-compaction-defer-each-zone-individually-instead-of-preferred-zone-fix.patch
mm-compaction-do-not-count-compact_stall-if-all-zones-skipped-compaction.patch
mm-compaction-do-not-recheck-suitable_migration_target-under-lock.patch
mm-compaction-move-pageblock-checks-up-from-isolate_migratepages_range.patch
mm-compaction-reduce-zone-checking-frequency-in-the-migration-scanner.patch
mm-compaction-khugepaged-should-not-give-up-due-to-need_resched.patch
mm-compaction-khugepaged-should-not-give-up-due-to-need_resched-fix.patch
mm-compaction-remember-position-within-pageblock-in-free-pages-scanner.patch
mm-compaction-skip-buddy-pages-by-their-order-in-the-migrate-scanner.patch
mm-rename-allocflags_to_migratetype-for-clarity.patch
mm-compaction-pass-gfp-mask-to-compact_control.patch
mm-use-__seq_open_private-instead-of-seq_open.patch
memcg-move-memcg_allocfree_cache_params-to-slab_commonc.patch
memcg-move-memcg_update_cache_size-to-slab_commonc.patch
zsmalloc-move-pages_allocated-to-zs_pool.patch
zsmalloc-change-return-value-unit-of-zs_get_total_size_bytes.patch
zram-zram-memory-size-limitation.patch
zram-report-maximum-used-memory.patch
page-owners-correct-page-order-when-to-free-page.patch
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