Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756122AbZF3FrU (ORCPT ); Tue, 30 Jun 2009 01:47:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752911AbZF3FrM (ORCPT ); Tue, 30 Jun 2009 01:47:12 -0400 Received: from smtp-out.google.com ([216.239.45.13]:49150 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752151AbZF3FrK (ORCPT ); Tue, 30 Jun 2009 01:47:10 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=bHjovFeYttKf3FCSizfmW+GzRy9+s4lMobbMPBxnxx6LEqppuP5Z0REDNV6N2+1Za jkConmdUJm9LuKYA6PbWQ== Date: Mon, 29 Jun 2009 22:47:03 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Larry Finger cc: "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Johannes Berg , Pekka Enberg , Christoph Lameter Subject: Re: [Bug #13319] Page allocation failures with b43 and p54usb In-Reply-To: <4A49733D.9030602@lwfinger.net> Message-ID: References: <5Hhc7UkUKEO.A.fNH.4kASKB@chimera> <4A48F114.1010702@lwfinger.net> <4A49733D.9030602@lwfinger.net> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1544 Lines: 29 On Mon, 29 Jun 2009, Larry Finger wrote: > > I'd disagree with disabling slub debugging by default for caches where > > oo_order(s->min) increases as the result of using it. This particular > > page allocation failure is happening for, presumably, kmalloc-4096, and > > the system has 4K pages. Disabling debugging for that cache (and any of > > its aliases) implicitly will lead to errors going undiagnosed as a result. > > If the current behavior is not changed, I will be forced to disable > SLUB debugging, which will explicitly lead to errors that are > undiagnosed. You're buying debugging support at the cost of increased memory consumption when you enable CONFIG_SLUB_DEBUG_ON and that's causing the page allocation failures because of fragmentation. To reduce the minimum order required for caches such as kmalloc-4096, you'd have to disable debugging for that particular cache. It's my opinion that such a configuration should not be the default, however. You could argue adding `slub_debug=-,kmalloc-4096' support from the command line, but CONFIG_SLUB_DEBUG_ON should not change its well-defined purpose of enabling debugging on all slab caches. Otherwise the rest of us would be forced to add `slub_debug=,kmalloc-4096' for consistent behavior with older kernels. -- 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/