From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id BD8F66B004A for ; Thu, 18 Nov 2010 04:16:25 -0500 (EST) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id oAI9GM5c006646 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 18 Nov 2010 18:16:23 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 926EE45DE5D for ; Thu, 18 Nov 2010 18:16:22 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 6DD7E45DE4E for ; Thu, 18 Nov 2010 18:16:22 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 4861BE08002 for ; Thu, 18 Nov 2010 18:16:22 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.249.87.105]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 049041DB8038 for ; Thu, 18 Nov 2010 18:16:22 +0900 (JST) Date: Thu, 18 Nov 2010 18:10:48 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 7/8] mm: compaction: Use the LRU to get a hint on where compaction should start Message-Id: <20101118181048.7bdfbb38.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <1290010969-26721-8-git-send-email-mel@csn.ul.ie> References: <1290010969-26721-1-git-send-email-mel@csn.ul.ie> <1290010969-26721-8-git-send-email-mel@csn.ul.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Andrea Arcangeli , KOSAKI Motohiro , Andrew Morton , Rik van Riel , Johannes Weiner , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Wed, 17 Nov 2010 16:22:48 +0000 Mel Gorman wrote: > The end of the LRU stores the oldest known page. Compaction on the other > hand always starts scanning from the start of the zone. This patch uses > the LRU to hint to compaction where it should start scanning from. This > means that compaction will at least start with some old pages reducing > the impact on running processes and reducing the amount of scanning. The > check it makes is racy as the LRU lock is not taken but it should be > harmless as we are not manipulating the lists without the lock. > > Signed-off-by: Mel Gorman Hmm, does this patch make a noticable difference ? Isn't it better to start scan from the biggest free chunk in a zone ? 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org