Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765562AbXHFUNe (ORCPT ); Mon, 6 Aug 2007 16:13:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757660AbXHFUNZ (ORCPT ); Mon, 6 Aug 2007 16:13:25 -0400 Received: from waste.org ([66.93.16.53]:60992 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758100AbXHFUNY (ORCPT ); Mon, 6 Aug 2007 16:13:24 -0400 Date: Mon, 6 Aug 2007 15:12:57 -0500 From: Matt Mackall To: Christoph Lameter Cc: Daniel Phillips , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Miller , Andrew Morton , Daniel Phillips , Pekka Enberg , Lee Schermerhorn , Steve Dickson Subject: Re: [PATCH 02/10] mm: system wide ALLOC_NO_WATERMARK Message-ID: <20070806201257.GG11115@waste.org> References: <20070806102922.907530000@chello.nl> <200708061121.50351.phillips@phunq.net> <200708061148.43870.phillips@phunq.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1370 Lines: 37 On Mon, Aug 06, 2007 at 11:51:45AM -0700, Christoph Lameter wrote: > On Mon, 6 Aug 2007, Daniel Phillips wrote: > > > On Monday 06 August 2007 11:42, Christoph Lameter wrote: > > > On Mon, 6 Aug 2007, Daniel Phillips wrote: > > > > Currently your system likely would have died here, so ending up > > > > with a reserve page temporarily on the wrong node is already an > > > > improvement. > > > > > > The system would have died? Why? > > > > Because a block device may have deadlocked here, leaving the system > > unable to clean dirty memory, or unable to load executables over the > > network for example. > > So this is a locking problem that has not been taken care of? No. It's very simple: 1) memory becomes full 2) we try to free memory by paging or swapping 3) I/O requires a memory allocation which fails because memory is full 4) box dies because it's unable to dig itself out of OOM Most I/O paths can deal with this by having a mempool for their I/O needs. For network I/O, this turns out to be prohibitively hard due to the complexity of the stack. -- Mathematics is the supreme nostalgia of our time. - 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/