Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751854AbWHNF3F (ORCPT ); Mon, 14 Aug 2006 01:29:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751855AbWHNF3F (ORCPT ); Mon, 14 Aug 2006 01:29:05 -0400 Received: from smtp.osdl.org ([65.172.181.4]:37294 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751854AbWHNF3C (ORCPT ); Mon, 14 Aug 2006 01:29:02 -0400 Date: Sun, 13 Aug 2006 22:22:08 -0700 From: Andrew Morton To: Peter Zijlstra Cc: Daniel Phillips , David Miller , riel@redhat.com, tgraf@suug.ch, linux-mm@kvack.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Mike Christie Subject: Re: [RFC][PATCH 2/9] deadlock prevention core Message-Id: <20060813222208.7e8583ac.akpm@osdl.org> In-Reply-To: <1155531835.5696.103.camel@twins> References: <20060808211731.GR14627@postel.suug.ch> <44DBED4C.6040604@redhat.com> <44DFA225.1020508@google.com> <20060813.165540.56347790.davem@davemloft.net> <44DFD262.5060106@google.com> <20060813185309.928472f9.akpm@osdl.org> <1155530453.5696.98.camel@twins> <20060813215853.0ed0e973.akpm@osdl.org> <1155531835.5696.103.camel@twins> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1646 Lines: 41 On Mon, 14 Aug 2006 07:03:55 +0200 Peter Zijlstra wrote: > On Sun, 2006-08-13 at 21:58 -0700, Andrew Morton wrote: > > On Mon, 14 Aug 2006 06:40:53 +0200 > > Peter Zijlstra wrote: > > > > > Testcase: > > > > > > Mount an NBD device as sole swap device and mmap > physical RAM, then > > > loop through touching pages only once. > > > > Fix: don't try to swap over the network. Yes, there may be some scenarios > > where people have no local storage, but it's reasonable to expect anyone > > who is using Linux as an "enterprise storage platform" to stick a local > > disk on the thing for swap. > > I wish you were right, however there seems to be a large demand to go > diskless and swap over iSCSI because disks seem to be the nr. 1 failing > piece of hardware in systems these days. We could track dirty anonymous memory and throttle. Also, there must be some value of /proc/sys/vm/min_free_kbytes at which a machine is no longer deadlockable with any of these tricks. Do we know what level that is? > > That leaves MAP_SHARED, but mm-tracking-shared-dirty-pages.patch will fix > > that, will it not? > > Will makes it less likely. One can still have memory pressure, the > remaining bits of memory can still get stuck in socket queues for > blocked processes. But there's lots of reclaimable pagecache around and kswapd will free it up? - 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/