From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 645686B004F for ; Mon, 15 Jun 2009 11:25:27 -0400 (EDT) Date: Mon, 15 Jun 2009 16:25:43 +0100 From: Mel Gorman Subject: Re: [PATCH 0/3] Fix malloc() stall in zone_reclaim() and bring behaviour more in line with expectations V3 Message-ID: <20090615152543.GF23198@csn.ul.ie> References: <20090611163006.e985639f.akpm@linux-foundation.org> <20090612110424.GD14498@csn.ul.ie> <20090615163018.B43A.A69D9226@jp.fujitsu.com> <20090615105651.GD23198@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: KOSAKI Motohiro , Andrew Morton , riel@redhat.com, fengguang.wu@intel.com, linuxram@us.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner List-ID: On Mon, Jun 15, 2009 at 11:01:41AM -0400, Christoph Lameter wrote: > On Mon, 15 Jun 2009, Mel Gorman wrote: > > > > May I ask your worry? > > > > > > > Simply that I believe the intention of PF_SWAPWRITE here was to allow > > zone_reclaim() to aggressively reclaim memory if the reclaim_mode allowed > > it as it was a statement that off-node accesses are really not desired. > > Right. > > > Ok. I am not fully convinced but I'll not block it either if believe it's > > necessary. My current understanding is that this patch only makes a difference > > if the server is IO congested in which case the system is struggling anyway > > and an off-node access is going to be relatively small penalty overall. > > Conceivably, having PF_SWAPWRITE set makes things worse in that situation > > and the patch makes some sense. > > We could drop support for RECLAIM_SWAP if that simplifies things. > I don't think that is necessary. While I expect it's very rarely used, I imagine a situation where it would be desirable on a system that had large amounts of tmpfs pages but where it wasn't critical they remain in-memory. Removing PF_SWAPWRITE would make it less aggressive and if you were happy with that, then that would be good enough for me. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org