Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932388AbWLLTWU (ORCPT ); Tue, 12 Dec 2006 14:22:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932392AbWLLTWU (ORCPT ); Tue, 12 Dec 2006 14:22:20 -0500 Received: from omx2-ext.sgi.com ([192.48.171.19]:51654 "EHLO omx2.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932388AbWLLTWT (ORCPT ); Tue, 12 Dec 2006 14:22:19 -0500 Date: Tue, 12 Dec 2006 11:22:11 -0800 (PST) From: Christoph Lameter To: Paul Jackson cc: jacliburn@bellsouth.net, akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] commit 3c517a61, slab: better fallback allocation behavior In-Reply-To: <20061212105717.f539fb73.pj@sgi.com> Message-ID: References: <457C64C5.9030108@bellsouth.net> <20061210124907.60c4a0aa.pj@sgi.com> <20061210141435.afac089d.akpm@osdl.org> <20061212105717.f539fb73.pj@sgi.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1043 Lines: 26 On Tue, 12 Dec 2006, Paul Jackson wrote: > Christoph wrote: > > + if (local_flags & __GFP_WAIT) > > + local_irq_enable(); > > + kmem_flagcheck(cache, flags); > > obj = kmem_getpages(cache, flags, -1); > > + if (local_flags & __GFP_WAIT) > > + local_irq_disable(); > > This seems strange to me. I am surprised that it is ok for a routine > that is called with irq's disabled, to enable them momentarilly. The slab itself disables the irq. In this case the slab function is was called irqs enabled and we forgot to reenable interrupts before calling kmem_getpages(). > I'd have thought the caller of this routine, who called it with irq's > disabled, would expect irq's to remain disabled across the entire call. Irqs only stay disabled if GFP_ATOMIC is passed to the slab function. - 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/