From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751754Ab1GUJfv (ORCPT ); Thu, 21 Jul 2011 05:35:51 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:59085 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751257Ab1GUJfs (ORCPT ); Thu, 21 Jul 2011 05:35:48 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Message-ID: <4E27F2EC.2010902@jp.fujitsu.com> Date: Thu, 21 Jul 2011 18:35:40 +0900 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ja; rv:1.9.2.18) Gecko/20110616 Lightning/1.0b2 Thunderbird/3.1.11 MIME-Version: 1.0 To: mgorman@suse.de CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] mm: page allocator: Reconsider zones for allocation after direct reclaim References: <1310389274-13995-1-git-send-email-mgorman@suse.de> <1310389274-13995-4-git-send-email-mgorman@suse.de> <4E1CE9FF.3050707@jp.fujitsu.com> <20110713111017.GG7529@suse.de> <4E1E6086.4060902@jp.fujitsu.com> <20110714061049.GK7529@suse.de> In-Reply-To: <20110714061049.GK7529@suse.de> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi >> So, I think we don't need to care zonelist, just kswapd turn off >> their own node. > > I don't understand what you mean by this. This was the answer of following your comments. > Instead, couldn't we turn zlc->fullzones off from kswapd? > > > > Which zonelist should it clear (there are two) I mean, buddy list is belong to zone, not zonelist. therefore, kswapd don't need to look up zonelist. So, I'd suggest either following way, - use direct reclaim path, but only clear a zlc bit of zones in reclaimed zonelist, not all. or - use kswapd and only clear a zlc bit at kswap exiting balance_pgdat I'm prefer to add a branch to slowpath (ie reclaim path) rather than fast path. >> And, just curious, If we will have a proper zlc clear point, why >> do we need to keep HZ timeout? > > Yes because we are not guaranteed to call direct reclaim either. Memory > could be freed by a process exiting and I'd rather not add cost to > the free path to find and clear all zonelists referencing the zone the > page being freed belongs to. Ok, it's good trade-off. I agree we need to keep HZ timeout.