Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754015AbXFIKJz (ORCPT ); Sat, 9 Jun 2007 06:09:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751733AbXFIKJr (ORCPT ); Sat, 9 Jun 2007 06:09:47 -0400 Received: from cantor.suse.de ([195.135.220.2]:33195 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751560AbXFIKJq (ORCPT ); Sat, 9 Jun 2007 06:09:46 -0400 From: Andi Kleen Organization: SUSE Linux Products GmbH, Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg) To: Christoph Lameter Subject: Re: [Intel-IOMMU 02/10] Library routine for pre-allocat pool handling Date: Sat, 9 Jun 2007 11:47:23 +0200 User-Agent: KMail/1.9.6 Cc: Andrew Morton , "Keshavamurthy, Anil S" , linux-kernel@vger.kernel.org, gregkh@suse.de, muli@il.ibm.com, asit.k.mallick@intel.com, suresh.b.siddha@intel.com, arjan@linux.intel.com, ashok.raj@intel.com, shaohua.li@intel.com, davem@davemloft.net References: <20070606185658.138237000@askeshav-devel.jf.intel.com> <200706090056.49279.ak@suse.de> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200706091147.24705.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1105 Lines: 29 > > Now there is a anon dirty limit since a few releases, but I'm not > > fully convinced it solves the problem completely. > > A gut feeling or is there more? Lots of other subsystem can allocate a lot of memory and they usually don't cooperate and have similar dirty limit concepts. So you could run out of usable memory anyways and then have a similar issue. For example a flood of network packets could always steal your GFP_ATOMIC pools very quickly in the background (gigabit or 10gig can transfer a lot of data very quickly) Also iirc try_to_free_pages() is not completely fair and might fail under extreme load for some requesters. Not requiring memory allocation for any IO would be certainly safer. Anyways, it's a theoretic question because you can't sleep in there anyways unless something drastic changes in the driver interfaces. -Andi - 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/