From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 30C6E6B0085 for ; Sun, 28 Nov 2010 21:13:58 -0500 (EST) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id oAT2DtUH020666 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Mon, 29 Nov 2010 11:13:55 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 14A8645DE4D for ; Mon, 29 Nov 2010 11:13:55 +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 EFB6C45DE61 for ; Mon, 29 Nov 2010 11:13:54 +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 DD15F1DB803F for ; Mon, 29 Nov 2010 11:13:54 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 9A9331DB803B for ; Mon, 29 Nov 2010 11:13:54 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH v2 1/3] deactivate invalidated pages In-Reply-To: <87pqto3n77.fsf@gmail.com> References: <20101129090514.829C.A69D9226@jp.fujitsu.com> <87pqto3n77.fsf@gmail.com> Message-Id: <20101129110848.82A8.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Mon, 29 Nov 2010 11:13:53 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Ben Gamari Cc: kosaki.motohiro@jp.fujitsu.com, Minchan Kim , Andrew Morton , linux-mm , LKML , Peter Zijlstra , Wu Fengguang , Rik van Riel , Johannes Weiner , Nick Piggin , Mel Gorman List-ID: > > I don't like this change because fadvise(DONT_NEED) is rarely used > > function and this PG_reclaim trick doesn't improve so much. In the > > other hand, It increase VM state mess. > > > > Can we please stop appealing to this argument? The reason that > fadvise(DONT_NEED) is currently rarely employed is that the interface as > implemented now is extremely kludgey to use. > > Are you proposing that this particular implementation is not worth the > mess (as opposed to putting the pages at the head of the inactive list > as done earlier) or would you rather that we simply leave DONT_NEED in > its current state? Even if today's gains aren't as great as we would > like them to be, we should still make an effort to make fadvise() > usable, if for no other reason than to encourage use in user-space so > that applications can benefit when we finally do figure out how to > properly account for the user's hints. Hi I'm not againt DONT_NEED feature. I only said PG_reclaim trick is not so effective. Every feature has their own pros/cons. I think the cons is too big. Also, nobody have mesured PG_reclaim performance gain. Did you? -- 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