From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752856Ab3ABPep (ORCPT ); Wed, 2 Jan 2013 10:34:45 -0500 Received: from mail-qc0-f178.google.com ([209.85.216.178]:57135 "EHLO mail-qc0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752755Ab3ABPem (ORCPT ); Wed, 2 Jan 2013 10:34:42 -0500 Date: Wed, 2 Jan 2013 10:34:39 -0500 From: Tejun Heo To: Rusty Russell Cc: Li Zefan , paul@paulmenage.org, glommer@parallels.com, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, peterz@infradead.org, mhocko@suse.cz, bsingharora@gmail.com, hannes@cmpxchg.org, kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 06/13] cpuset: cleanup cpuset[_can]_attach() Message-ID: <20130102153439.GA11220@mtj.dyndns.org> References: <1354138460-19286-1-git-send-email-tj@kernel.org> <1354138460-19286-7-git-send-email-tj@kernel.org> <50DACF5B.6050705@huawei.com> <20121226120415.GA18193@mtj.dyndns.org> <87zk0s5h7c.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87zk0s5h7c.fsf@rustcorp.com.au> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Rusty. On Wed, Jan 02, 2013 at 03:12:15PM +1030, Rusty Russell wrote: > > Hmmm? cpumask_t can't be used for stack but other than that I don't > > see how it would be deprecated completely. Rusty, can you please > > chime in? > > The long-never-quite-complete-plan was for struct cpumask to be > undefined when CONFIG_CPUMASK_OFFSTACK=y. That means noone can declare > them, or pass them on the stack, since they'll get a compiler error. > > Now, there are some cases where it really is a reason to use a static > bitmap, and 1/2 a K of wasted space be damned. There's a > deliberately-ugly way of doing that: declare a bitmap and use > to_cpumask(). Of course, if we ever really want to remove NR_CPUS and > make it completely generic, we have to kill all these too, but noone is > serious about that. So, I guess this currently is caught in a place which isn't here or there. I'm pretty skeptical whether it makes sense to bother about static usages tho. Can I keep them for static ones? Thanks. -- tejun