From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 6213D6B003D for ; Wed, 11 Feb 2009 19:02:04 -0500 (EST) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n1C020MT030744 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 12 Feb 2009 09:02:01 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id A811845DE5B for ; Thu, 12 Feb 2009 09:02:00 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 6C33345DD83 for ; Thu, 12 Feb 2009 09:02:00 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 34C26E08008 for ; Thu, 12 Feb 2009 09:02:00 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.249.87.103]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id BA51B1DB8044 for ; Thu, 12 Feb 2009 09:01:56 +0900 (JST) Date: Thu, 12 Feb 2009 09:00:43 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] mm: remove zone->prev_prioriy Message-Id: <20090212090043.b07d6540.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090211201706.C3C0.KOSAKI.MOTOHIRO@jp.fujitsu.com> References: <20090211195252.C3BD.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20090211031201.cace1c68.akpm@linux-foundation.org> <20090211201706.C3C0.KOSAKI.MOTOHIRO@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Andrew Morton , MinChan Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org, riel@redhat.com List-ID: On Wed, 11 Feb 2009 20:23:39 +0900 (JST) KOSAKI Motohiro wrote: > > On Wed, 11 Feb 2009 20:06:46 +0900 (JST) KOSAKI Motohiro wrote: > > > > > > On Tue, 10 Feb 2009 19:57:01 +0900 > > > > MinChan Kim wrote: > > > > > > > > > As you know, prev_priority is used as a measure of how much stress page reclaim. > > > > > But now we doesn't need it due to split-lru's way. > > > > > > > > > > I think it would be better to remain why prev_priority isn't needed any more > > > > > and how split-lru can replace prev_priority's role in changelog. > > > > > > > > > > In future, it help mm newbies understand change history, I think. > > > > > > > > Yes, I'd be fascinated to see that explanation. > > > > > > > > In http://groups.google.pn/group/linux.kernel/browse_thread/thread/fea9c9a0b43162a1 > > > > it was asserted that we intend to use prev_priority again in the future. > > > > > > > > We discussed this back in November: > > > > http://lkml.indiana.edu/hypermail/linux/kernel/0811.2/index.html#00001 > > > > > > > > And I think that I still think that the VM got worse due to its (new) > > > > failure to track previous state. IIRC, the response to that concern > > > > was quite similar to handwavy waffling. > > > > > > Yes. > > > I still think it's valuable code. > > > I think, In theory, VM sould take parallel reclaim bonus. > > > > prev_priority had nothing to do with concurrent reclaim? > > > > It was there so that when a task enters direct reclaim against a zone, > > it will immediately adopt the state which the task which most recently > > ran direct reclaim had. > > > > Without this feature, each time a task enters direct reclaim it will need > > to "relearn" that state - ramping up, making probably-incorrect > > decisions as it does so. > > Yes, I perfectly agree to you. > theorically, prev_priority is very valuable stuff. > Ok, please implement the lost logic again. -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/ . Don't email: email@kvack.org