From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261876AbVFGOVT (ORCPT ); Tue, 7 Jun 2005 10:21:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261878AbVFGOVS (ORCPT ); Tue, 7 Jun 2005 10:21:18 -0400 Received: from dgate1.fujitsu-siemens.com ([217.115.66.35]:44186 "EHLO dgate1.fujitsu-siemens.com") by vger.kernel.org with ESMTP id S261876AbVFGOVF (ORCPT ); Tue, 7 Jun 2005 10:21:05 -0400 X-SBRSScore: None X-IronPort-AV: i="3.93,179,1114984800"; d="scan'208"; a="10543370:sNHT29722276" Message-ID: <42A5AD4A.6080100@fujitsu-siemens.com> Date: Tue, 07 Jun 2005 16:20:58 +0200 From: Martin Wilck Organization: Fujitsu Siemens Computers User-Agent: Mozilla Thunderbird 0.5 (X11/20040208) X-Accept-Language: de, en-us, en MIME-Version: 1.0 To: Andrew Morton Cc: linux-kernel@vger.kernel.org Subject: Re: RFC for 2.6: avoid OOM at bounce buffer storm References: <42A07BAA.4050303@fujitsu-siemens.com> <20050603160629.2acc4558.akpm@osdl.org> In-Reply-To: <20050603160629.2acc4558.akpm@osdl.org> 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 Andrew Morton wrote: > It might be neater to do this at the mempool level: that way we're adding > general-purpose infrastructure and then just using it, rather than > special-casing the bounce code. > > See below a (n untested) patch against the latest devel tree. It won't be > stunningly scalable on big SMP, but the overhead of bouncing will probably > hide that. I don't quite understand your patch. You introduce a "limit" field but you never actually use it. You also don't count the allocated pages. Are you using the semaphore for slowing things down on purpose? (Note that the problem is not in the mempool allocation itself but in the "normal" allocation path (page_pool_alloc() -> alloc_page())) Anyway, I think could figure out your patch but with 2.6.12-rc5-mm2 I couldn't reproduce the problem any more. It appears to run much more smoothly now, perhaps because wakeup_bdflush() isn't called any more. Are you still interested in more data? >>I couldn't get 2.6.12-rc5 to run on my system. > > Ow. Could you please investigate further? Any boot messages for us to > see? it's quite possibly some missing config option.. It turned out to be a problem with Red Hat's nash that didn't check the returned pid in it's wait4() call and thus ended up insmod'ing mutliple modules simultaneously, leading to "Unkown symbol" errors. Yuck, it took me a day figure that out. That bug is fixed in redhat's "mkinitrd" package 4.2.0.3-1 and later, but that package is currently only in Fedora's "Development" tree. Thanks, Martin -- Martin Wilck Phone: +49 5251 8 15113 Fujitsu Siemens Computers Fax: +49 5251 8 20409 Heinz-Nixdorf-Ring 1 mailto:Martin.Wilck@Fujitsu-Siemens.com D-33106 Paderborn http://www.fujitsu-siemens.com/primergy