Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753460Ab2EJBdH (ORCPT ); Wed, 9 May 2012 21:33:07 -0400 Received: from mail-qa0-f49.google.com ([209.85.216.49]:43160 "EHLO mail-qa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750706Ab2EJBdD (ORCPT ); Wed, 9 May 2012 21:33:03 -0400 Message-ID: <4FAB1AC9.1050306@gmail.com> Date: Wed, 09 May 2012 21:32:57 -0400 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Rusty Russell CC: Ingo Molnar , x86@kernel.org, LKML , anton@samba.org, Arnd Bergmann , KOSAKI Motohiro , Mike Travis , Thomas Gleixner , Linus Torvalds , Al Viro , kosaki.motohiro@gmail.com Subject: Re: [PULL] cpumask: finally make them variable size w/ CPUMASK_OFFSTACK. References: <87ipg5c2bk.fsf@rustcorp.com.au> In-Reply-To: <87ipg5c2bk.fsf@rustcorp.com.au> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1688 Lines: 46 (5/9/12 2:10 AM), Rusty Russell wrote: > Hi Ingo, > > I finally rebased this on top of your tip tree, and tested it > locally. Some more old-style cpumask usages have crept in, but it's a > fairly simple series. > > The final result is that if you enable CONFIG_CPUMASK_OFFSTACK, then > 'struct cpumask' becomes an undefined type. You can't accidentally take > the size of it, assign it, or pass it by value. And thus it's safe for > us to make it smaller if nr_cpu_ids< NR_CPUS, as the final patch does. > > It unfortunately requires the lglock cleanup patch, which Al already has > queued, so I've included it here. Hi Thanks this effort. This is very cleaner than I expected. However I should NAK following one patch. sorry. because of, lru-drain is called from memory reclaim context. It mean, additional allocation may not work. Please just use bare NR_CPUS bitmap instead. space wasting is minor issue than that. > commit fab26054c0500d426cf1bc2ce227a6a428dc815e > Author: Rusty Russell > Date: Wed May 9 14:55:15 2012 +0930 > > page_alloc: use cpumask_var_t. > > The BSS trick works, but it still wastes space. Especially since there's > a nice fallback in the case where we fail to allocate a temporary cpumask. > > Signed-off-by: Rusty Russell Other patches looks very goold. Acked-by: KOSAKI Motohiro Thanks. -- 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/