Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758605AbYC1UZn (ORCPT ); Fri, 28 Mar 2008 16:25:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758215AbYC1UZc (ORCPT ); Fri, 28 Mar 2008 16:25:32 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:40014 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758383AbYC1UZ3 (ORCPT ); Fri, 28 Mar 2008 16:25:29 -0400 Date: Fri, 28 Mar 2008 13:24:56 -0700 (PDT) From: Linus Torvalds To: Pekka Enberg cc: Christoph Lameter , "Rafael J. Wysocki" , Pawel Staszewski , LKML , Adrian Bunk , Andrew Morton , Natalie Protasevich Subject: Re: 2.6.25-rc7-git2: Reported regressions from 2.6.24 In-Reply-To: <47ED4E33.9070203@cs.helsinki.fi> Message-ID: References: <200803272353.51901.rjw@sisk.pl> <84144f020803281015s60370d9dpec0913c33004b6c2@mail.gmail.com> <84144f020803281108o178bf62cp48dcd4f43ec59b74@mail.gmail.com> <47ED4E33.9070203@cs.helsinki.fi> User-Agent: Alpine 1.00 (LFD 882 2007-12-20) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1032 Lines: 24 On Fri, 28 Mar 2008, Pekka Enberg wrote: > > Because I didn't spot that we're calling kmalloc_large() in the fallback path > too. I was referring to the page allocator pass-through kmalloc_large() call > that happens before we hit __slab_alloc. My bad, sorry. So this is kind of my point of the whole thing. It's really hard to even realize that there are multiple points - unless you do it at the top level. And yeah, the double clearing is just a performance issue in a rare and odd case, and if it hadn't been for the very anal debug checks we would never have even noticed. But code that is hard to follow and has really subtle non-local implications is fundamentally more likely to have these kinds of problems. Which is why I'm arguing against code like that. Linus -- 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/