Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932333Ab0HDKAU (ORCPT ); Wed, 4 Aug 2010 06:00:20 -0400 Received: from alpha.arachsys.com ([91.203.57.7]:51836 "EHLO alpha.arachsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932090Ab0HDKAS (ORCPT ); Wed, 4 Aug 2010 06:00:18 -0400 Date: Wed, 4 Aug 2010 10:58:12 +0100 From: Chris Webb To: Wu Fengguang Cc: Minchan Kim , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , KOSAKI Motohiro , Pekka Enberg Subject: Re: Over-eager swapping Message-ID: <20100804095811.GC2326@arachsys.com> References: <20100802124734.GI2486@arachsys.com> <20100803033108.GA23117@arachsys.com> <20100803042835.GA17377@localhost> <20100803214945.GA2326@arachsys.com> <20100804022148.GA5922@localhost> <20100804032400.GA14141@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100804032400.GA14141@localhost> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 34 Wu Fengguang writes: > This is interesting. Why is it waiting for 1m here? Are there high CPU > loads? Would you do a > > echo t > /proc/sysrq-trigger > > and show us the dmesg? Annoyingly, magic-sysrq isn't compiled in on these kernels. Is there another way I can get this info for you? Replacing the kernels on the machines is a painful job as I have to give the clients running on them quite a bit of notice of the reboot, and I haven't been able to reproduce the problem on a test machine. I also think the swap use is much better following a reboot, and only starts to spiral out of control after the machines have been running for a week or so. However, your suggestion is right that the CPU loads on these machines are typically quite high. The large number of kvm virtual machines they run mean thatl oads of eight or even sixteen in /proc/loadavg are not unusual, and these are higher when there's swap than after it has been removed. I assume this is mostly because of increased IO wait, as this number increases significantly in top. Cheers, Chris. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/