From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S275240AbTHMPg7 (ORCPT ); Wed, 13 Aug 2003 11:36:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S275239AbTHMPg7 (ORCPT ); Wed, 13 Aug 2003 11:36:59 -0400 Received: from fep05-svc.mail.telepac.pt ([194.65.5.209]:22939 "EHLO fep05-svc.mail.telepac.pt") by vger.kernel.org with ESMTP id S275251AbTHMPfv (ORCPT ); Wed, 13 Aug 2003 11:35:51 -0400 Message-ID: <3F3A5B06.7050103@vgertech.com> Date: Wed, 13 Aug 2003 16:36:38 +0100 From: Nuno Silva Organization: VGER, LDA User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030714 Debian/1.4-2 X-Accept-Language: en-us, pt MIME-Version: 1.0 To: Ken Savage CC: linux-kernel@vger.kernel.org Subject: Re: High CPU load with kswapd and heavy disk I/O References: <200308121136.11979.kens1835@shaw.ca> <200308121323.49081.kens1835@shaw.ca> <3F397CED.6060006@vgertech.com> <200308121714.36993.kens1835@shaw.ca> In-Reply-To: <200308121714.36993.kens1835@shaw.ca> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! Ken Savage wrote: > On Tue August 12 2003 16:49, Nuno Silva wrote: > > >>My guess is that this is the cause. LOWMEM pressure because of very >>large directories... Relating to this, linux-2.6.0-test3-mm1 has Ingo's >>4G/4G memory split. Can you try this kernel, enable 4G/4G feature, and >>report back? > > > Something about the 2.6 (and the rmap patched 2.4) kernels causes > lockouts on the server -- for reasons OTHER than kswapd. The server If you want to help, you could try to gather more info on that to help develope a better 2.6 ;) FWIW, 2.6.0-test* with mm patches works well here... At least in a few boxes. > running the delete-old-files process runs hundreds of other CPU and disk > I/O intensive processes/threads, and it doesn't look like 2.6 is yet able > to handle the load. Unfortunately, the server is a production environment > machine at a remote site, so lockouts/reboots/kernel panics are baaaad :( > > I've seen other mentions of kswapd/kupdated problems in 2.4.xx, but > few mentions of solutions. Have people just learned to avoid the > situations that trigger the mad thrashes? > If you're sure that it's really kswapd you can send SIGSTOP and SIGCONT to kswapd's pid. Kswapd will honor those signals. killall -STOP kswapd killall -CONT kswapd Sometimes I do this... For me it works well. If this makes your machine crash or loose data, don't blame me! ;) Regards, Nuno Silva > Ken > - > 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/ >