Return-path: Received: from gir.skynet.ie ([193.1.99.77]:57796 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753476AbZIKIrM (ORCPT ); Fri, 11 Sep 2009 04:47:12 -0400 Date: Fri, 11 Sep 2009 09:47:17 +0100 From: Mel Gorman To: reinette chatre Cc: Frans Pop , Larry Finger , "John W. Linville" , Pekka Enberg , "linux-kernel@vger.kernel.org" , "linux-wireless@vger.kernel.org" , "ipw3945-devel@lists.sourceforge.net" , Andrew Morton , "cl@linux-foundation.org" , "Krauss, Assaf" , Johannes Berg , "Abbas, Mohamed" Subject: Re: iwlagn: order 2 page allocation failures Message-ID: <20090911084717.GB32497@csn.ul.ie> References: <200909060941.01810.elendil@planet.nl> <4AA67139.80301@lwfinger.net> <20090909150418.GI24614@csn.ul.ie> <200909091759.33655.elendil@planet.nl> <20090909165545.GK24614@csn.ul.ie> <1252526738.30150.91.camel@rc-desk> <20090910090206.GA22276@csn.ul.ie> <1252617290.30150.321.camel@rc-desk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 In-Reply-To: <1252617290.30150.321.camel@rc-desk> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, Sep 10, 2009 at 02:14:50PM -0700, reinette chatre wrote: > On Thu, 2009-09-10 at 02:02 -0700, Mel Gorman wrote: > > > > > As a total aside, there is still the problem that the driver is depending on > > order-2 allocations. On systems without swap, the allocation problem could be > > more severe as there are fewer pages the system can use to regain contiguity. > > I looked more at the implementation and hardware interface but I do not > see a way around this. We have to provide 8k buffer to device, and we > have to make sure it is aligned. > That would imply an order-1 allocation instead of an order-2 though so it would appear than we are being worse than we have to. It would appear to be because of this +256 bytes that goes onto every buffer. > Do you have any suggestions? > Nothing concrete. Finding an alternative to having the socket buffer 8192+256 to make it an order-1 allocation would be an improvement but I don't know how that should be tackled. Lacking the hardware, I can't experiment myself :( -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab