Return-path: Received: from gir.skynet.ie ([193.1.99.77]:41830 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754029AbZIHLAi (ORCPT ); Tue, 8 Sep 2009 07:00:38 -0400 Date: Tue, 8 Sep 2009 12:00:41 +0100 From: Mel Gorman To: Theodore Tso , "Luis R. Rodriguez" , Bartlomiej Zolnierkiewicz , "Aneesh Kumar K.V" , Zhu Yi , Andrew Morton , Johannes Weiner , Pekka Enberg , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Mel Gorman , "netdev@vger.kernel.org" , "linux-mm@kvack.org" , James Ketrenos , "Chatre, Reinette" , "linux-wireless@vger.kernel.org" , "ipw2100-devel@lists.sourceforge.net" Subject: Re: ipw2200: firmware DMA loading rework Message-ID: <20090908110041.GE28127@csn.ul.ie> References: <1251430951.3704.181.camel@debian> <200908301437.42133.bzolnier@gmail.com> <200909021948.13262.bzolnier@gmail.com> <43e72e890909021102g7f844c79xefccf305f5f5c5b6@mail.gmail.com> <20090903124913.GA26110@csn.ul.ie> <20090905142837.GI16217@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 In-Reply-To: <20090905142837.GI16217@mit.edu> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sat, Sep 05, 2009 at 10:28:37AM -0400, Theodore Tso wrote: > On Thu, Sep 03, 2009 at 01:49:14PM +0100, Mel Gorman wrote: > > > > > > This looks very similar to the kmemleak ext4 reports upon a mount. If > > > it is the same issue, which from the trace it seems it is, then this > > > is due to an extra kmalloc() allocation and this apparently will not > > > get fixed on 2.6.31 due to the closeness of the merge window and the > > > non-criticalness this issue has been deemed. > > No, it's a different problem. > > > I suspect the more pressing concern is why is this kmalloc() resulting in > > an order-5 allocation request? What size is the buffer being requested? > > Was that expected? What is the contents of /proc/slabinfo in case a buffer > > that should have required order-1 or order-2 is using a higher order for > > some reason. > > It's allocating 68,000 bytes for the mb_history structure, which is > used for debugging purposes. That's why it's optional and we continue > if it's not allocated. We should fix it to use vmalloc() You could call with kmalloc(FLAGS|GFP_NOWARN) with a fallback to vmalloc() and a disable if vmalloc() fails as well. Maybe check out what kernel/profile.c#profile_init() to allocate a large buffer and do something similar? > and I'm > inclined to turn it off by default since it's not worth the overhead, > and most ext4 users won't find it useful or interesting. > I can't comment as I don't know what sort of debugging it's useful for. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab