Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752467Ab3JQGD0 (ORCPT ); Thu, 17 Oct 2013 02:03:26 -0400 Received: from lgeamrelo01.lge.com ([156.147.1.125]:51353 "EHLO LGEAMRELO01.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751073Ab3JQGC7 (ORCPT ); Thu, 17 Oct 2013 02:02:59 -0400 X-AuditID: 9c93017d-b7b2eae000005519-3c-525f7d906d4d From: Joonsoo Kim To: Pekka Enberg Cc: Christoph Lameter , Andrew Morton , Joonsoo Kim , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wanpeng Li , Joonsoo Kim Subject: [PATCH v2 5/5] slab: make more slab management structure off the slab Date: Thu, 17 Oct 2013 15:03:17 +0900 Message-Id: <1381989797-29269-6-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1381989797-29269-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1381989797-29269-1-git-send-email-iamjoonsoo.kim@lge.com> X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1382 Lines: 35 Now, the size of the freelist for the slab management diminish, so that the on-slab management structure can waste large space if the object of the slab is large. Consider a 128 byte sized slab. If on-slab is used, 31 objects can be in the slab. The size of the freelist for this case would be 31 bytes so that 97 bytes, that is, more than 75% of object size, are wasted. In a 64 byte sized slab case, no space is wasted if we use on-slab. So set off-slab determining constraint to 128 bytes. Acked-by: Christoph Lameter Signed-off-by: Joonsoo Kim diff --git a/mm/slab.c b/mm/slab.c index 2f379ba..19ae154 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2257,7 +2257,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) * it too early on. Always use on-slab management when * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak) */ - if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init && + if ((size >= (PAGE_SIZE >> 5)) && !slab_early_init && !(flags & SLAB_NOLEAKTRACE)) /* * Size is large, assume best to place the slab management obj -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/