From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx128.postini.com [74.125.245.128]) by kanga.kvack.org (Postfix) with SMTP id A9CD76B0038 for ; Mon, 2 Sep 2013 04:38:17 -0400 (EDT) From: Joonsoo Kim Subject: [PATCH 4/4] slab: make more slab management structure off the slab Date: Mon, 2 Sep 2013 17:38:58 +0900 Message-Id: <1378111138-30340-5-git-send-email-iamjoonsoo.kim@lge.com> In-Reply-To: <1378111138-30340-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1378111138-30340-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Christoph Lameter , Andrew Morton , Joonsoo Kim , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim 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. Signed-off-by: Joonsoo Kim diff --git a/mm/slab.c b/mm/slab.c index bd366e5..d01a2f0 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2277,7 +2277,7 @@ __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, 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