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 CD7006B00AA for ; Tue, 12 Oct 2010 00:07:38 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o9C47bJ2020405 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 12 Oct 2010 13:07:38 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id C4A8D45DE70 for ; Tue, 12 Oct 2010 13:07:37 +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 9A97945DE6F for ; Tue, 12 Oct 2010 13:07:37 +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 7AF511DB803B for ; Tue, 12 Oct 2010 13:07:37 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 2AE5F1DB803A for ; Tue, 12 Oct 2010 13:07:37 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [resend][PATCH] mm: increase RECLAIM_DISTANCE to 30 In-Reply-To: References: <20101012111451.AD2E.A69D9226@jp.fujitsu.com> Message-Id: <20101012130806.AD37.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 12 Oct 2010 13:07:35 +0900 (JST) Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: kosaki.motohiro@jp.fujitsu.com, Christoph Lameter , Balbir Singh , Mel Gorman , Rob Mueller , linux-kernel@vger.kernel.org, Bron Gondwana , linux-mm List-ID: > On Tue, 12 Oct 2010, KOSAKI Motohiro wrote: > > > > It doesn't determine what the maximum latency to that memory is, it relies > > > on whatever was defined in the SLIT; the only semantics of that distance > > > comes from the ACPI spec that states those distances are relative to the > > > local distance of 10. > > > > Right. but do we need to consider fake SLIT case? I know actually such bogus > > slit are there. but I haven't seen such fake SLIT made serious trouble. > > > > If we can make the assumption that the SLIT entries are truly > representative of the latencies and are adhering to the semantics > presented in the ACPI spec, then this means the VM prefers to do zone > reclaim rather than from other nodes when the latter is 3x more costly. > > That's fine by me, as I've mentioned we've done this for a couple years > because we've had to explicitly disable zone_reclaim_mode for such > configurations. If that's the policy decision that's been made, though, > we _could_ measure the cost at boot and set zone_reclaim_mode depending on > the measured latency rather than relying on the SLIT at all in this case. ok, got it. thanks. -- 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