From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 10 Apr 2007 14:21:07 -0700 (PDT) From: Christoph Lameter Subject: Re: [SLUB 3/5] Validation of slabs (metadata and guard zones) In-Reply-To: <20070410133137.e366a16b.akpm@linux-foundation.org> Message-ID: References: <20070410191910.8011.76133.sendpatchset@schroedinger.engr.sgi.com> <20070410191921.8011.16929.sendpatchset@schroedinger.engr.sgi.com> <20070410133137.e366a16b.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-mm@kvack.org List-ID: On Tue, 10 Apr 2007, Andrew Morton wrote: > Where do I go to learn what "s->defrag_ratio = 100;" means? SLUB: add explanation for defrag_ratio = 100. Signed-off-by: Christoph Lameter Index: linux-2.6.21-rc6/mm/slub.c =================================================================== --- linux-2.6.21-rc6.orig/mm/slub.c 2007-04-10 14:16:33.000000000 -0700 +++ linux-2.6.21-rc6/mm/slub.c 2007-04-10 14:19:05.000000000 -0700 @@ -961,6 +961,12 @@ static struct page *get_any_partial(stru * * A higher ratio means slabs may be taken from other nodes * thus reducing the number of partial slabs on those nodes. + * + * If /sys/slab/xx/defrag_ratio is set to 100 (which makes + * defrag_ratio = 1000) then every (well almost) allocation + * will first attempt to defrag slab caches on other nodes. This + * means scanning over all nodes to look for partial slabs which + * may be a bit expensive to do on every slab allocation. */ if (!s->defrag_ratio || get_cycles() % 1024 > s->defrag_ratio) return NULL; -- 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