Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757534Ab1DZTvP (ORCPT ); Tue, 26 Apr 2011 15:51:15 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:44429 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756611Ab1DZTvN (ORCPT ); Tue, 26 Apr 2011 15:51:13 -0400 Date: Tue, 26 Apr 2011 12:47:43 -0700 From: Andrew Morton To: Wu Fengguang Cc: Minchan Kim , Dave Young , linux-mm , Linux Kernel Mailing List , Mel Gorman Subject: Re: readahead and oom Message-Id: <20110426124743.e58d9746.akpm@linux-foundation.org> In-Reply-To: <20110426092029.GA27053@localhost> References: <20110426055521.GA18473@localhost> <20110426062535.GB19717@localhost> <20110426063421.GC19717@localhost> <20110426092029.GA27053@localhost> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1128 Lines: 26 On Tue, 26 Apr 2011 17:20:29 +0800 Wu Fengguang wrote: > Pass __GFP_NORETRY|__GFP_NOWARN for readahead page allocations. > > readahead page allocations are completely optional. They are OK to > fail and in particular shall not trigger OOM on themselves. I have distinct recollections of trying this many years ago, finding that it caused problems then deciding not to do it. But I can't find an email trail and I don't remember the reasons :( If the system is so stressed for memory that the oom-killer might get involved then the readahead pages may well be getting reclaimed before the application actually gets to use them. But that's just an aside. Ho hum. The patch *seems* good (as it did 5-10 years ago ;)) but there may be surprising side-effects which could be exposed under heavy testing. Testing which I'm sure hasn't been performed... -- 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/