From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id 2131F6B0036 for ; Mon, 15 Sep 2014 02:26:02 -0400 (EDT) Received: by mail-pa0-f54.google.com with SMTP id lj1so5782124pab.27 for ; Sun, 14 Sep 2014 23:26:01 -0700 (PDT) Received: from lgeamrelo04.lge.com (lgeamrelo04.lge.com. [156.147.1.127]) by mx.google.com with ESMTP id vv6si20865074pab.144.2014.09.14.23.25.59 for ; Sun, 14 Sep 2014 23:26:00 -0700 (PDT) From: Joonsoo Kim Subject: [PATCH v2 2/3] mm/slab: support slab merge Date: Mon, 15 Sep 2014 15:25:56 +0900 Message-Id: <1410762357-7787-2-git-send-email-iamjoonsoo.kim@lge.com> In-Reply-To: <1410762357-7787-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1410762357-7787-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Christoph Lameter , Pekka Enberg , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim 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 Slab: 25136 kB 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. v2: add commit description for the reason to implement SLAB specific functions. Signed-off-by: Joonsoo Kim --- mm/slab.c | 20 ++++++++++++++++++++ mm/slab.h | 2 +- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/mm/slab.c b/mm/slab.c index 5927a17..cc246f2 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2104,6 +2104,26 @@ static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) 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 --git a/mm/slab.h b/mm/slab.h index 857758b..46c7c25 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -90,7 +90,7 @@ 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 *)); -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org