From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 707C48D0039 for ; Wed, 23 Feb 2011 18:59:09 -0500 (EST) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 0D44B3EE081 for ; Thu, 24 Feb 2011 08:59:04 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id E190E45DE51 for ; Thu, 24 Feb 2011 08:59:03 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id C81B745DE4F for ; Thu, 24 Feb 2011 08:59:03 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id B8C291DB8040 for ; Thu, 24 Feb 2011 08:59:03 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 845FB1DB802F for ; Thu, 24 Feb 2011 08:59:03 +0900 (JST) Date: Thu, 24 Feb 2011 08:52:27 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC PATCH] page_cgroup: Reduce allocation overhead for page_cgroup array for CONFIG_SPARSEMEM Message-Id: <20110224085227.1a3e185b.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <1298485162.7236.4.camel@nimitz> References: <20110223151047.GA7275@tiehlicka.suse.cz> <1298485162.7236.4.camel@nimitz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, 23 Feb 2011 10:19:22 -0800 Dave Hansen wrote: > On Wed, 2011-02-23 at 16:10 +0100, Michal Hocko wrote: > > We can reduce this internal fragmentation by splitting the single > > page_cgroup array into more arrays where each one is well kmalloc > > aligned. This patch implements this idea. > > How about using alloc_pages_exact()? These things aren't allocated > often enough to really get most of the benefits of being in a slab. > That'll at least get you down to a maximum of about PAGE_SIZE wasted. > yes, alloc_pages_exact() is much better. packing page_cgroups for multiple sections causes breakage in memory hotplug logic. Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org