From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 03 Sep 2008 05:05:43 -0700 (PDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.168.29]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m83C59Mt021776 for ; Wed, 3 Sep 2008 05:05:10 -0700 Date: Wed, 3 Sep 2008 08:06:35 -0400 From: Christoph Hellwig Subject: Re: [PATCH] Tweak tracing allocation sizes Message-ID: <20080903120635.GA14662@infradead.org> References: <48BCD3BE.5040107@sgi.com> <20080902055604.GD15962@disturbed> <48BCD93E.9040407@sgi.com> <87fxojvy5v.fsf@basil.nowhere.org> <20080902215516.GE9204@infradead.org> <20080903070654.GP18288@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080903070654.GP18288@one.firstfloor.org> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Andi Kleen Cc: Christoph Hellwig , lachlan@sgi.com, xfs-dev , xfs-oss On Wed, Sep 03, 2008 at 09:06:54AM +0200, Andi Kleen wrote: > On Tue, Sep 02, 2008 at 05:55:16PM -0400, Christoph Hellwig wrote: > > On Tue, Sep 02, 2008 at 08:50:52AM +0200, Andi Kleen wrote: > > > > alternative - maybe a very large global trace buffer that is allocated at mount > > > > time and shared by all inodes? > > > > > > You could use vmalloc(). While that is also not fast it will at least > > > not stall. > > > > In fact kmem_alloc first tries vmalloc, and then falls back to slab > > when it fails. See fs/xfs/linux-2.6/kmem.c:kmem_alloc(). > > You mean the other way around? No, take a look at the function. I guess the intent is that vmalloc can fail due to a full vmalloc area and kmalloc could theoretically still scucceed.