From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754158AbaHUILb (ORCPT ); Thu, 21 Aug 2014 04:11:31 -0400 Received: from lgeamrelo01.lge.com ([156.147.1.125]:50686 "EHLO lgeamrelo01.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751962AbaHUIL2 (ORCPT ); Thu, 21 Aug 2014 04:11:28 -0400 X-Original-SENDERIP: 10.177.222.131 X-Original-MAILFROM: iamjoonsoo.kim@lge.com From: Joonsoo Kim To: Andrew Morton Cc: Christoph Lameter , Pekka Enberg , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim Subject: [PATCH 3/3] mm/slab: support slab merge Date: Thu, 21 Aug 2014 17:11:15 +0900 Message-Id: <1408608675-20420-3-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1408608675-20420-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1408608675-20420-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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 09b060e..a1cc1c9 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2052,6 +2052,26 @@ 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 7c6e1ed..13845d0 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -89,7 +89,7 @@ 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