From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752437Ab1LBFeR (ORCPT ); Fri, 2 Dec 2011 00:34:17 -0500 Received: from mailout-de.gmx.net ([213.165.64.22]:57227 "HELO mailout-de.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751602Ab1LBFeN (ORCPT ); Fri, 2 Dec 2011 00:34:13 -0500 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX196intZjlV6Tk4ZDM0js0AoYLT71TjGSIbX3eai4r ATrsoO4I8NJi2p Subject: Re: [PATCH] jump_label: jump_label for boot options. From: Mike Galbraith To: KAMEZAWA Hiroyuki Cc: Jason Baron , "linux-kernel@vger.kernel.org" , Peter Zijlstra , Jeremy Fitzhardinge , rostedt@goodmis.org In-Reply-To: <20111202092837.58e11827.kamezawa.hiroyu@jp.fujitsu.com> References: <20111201115353.563f79fc.kamezawa.hiroyu@jp.fujitsu.com> <20111201154036.GA2443@redhat.com> <20111202092837.58e11827.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 02 Dec 2011 06:34:05 +0100 Message-ID: <1322804045.4755.13.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2011-12-02 at 09:28 +0900, KAMEZAWA Hiroyuki wrote: > On Thu, 1 Dec 2011 10:40:36 -0500 > Jason Baron wrote: > > > On Thu, Dec 01, 2011 at 11:53:53AM +0900, KAMEZAWA Hiroyuki wrote: > > > I tried to use jump_label for handling memcg's boot options which sets > > > global variable true/false and never changes after boot. And found jump_table > > > is larger than expected. This patch is a trial to allow to place jump_table > > > in .init section. How do you think ? > > > > > > > Remeber too, that 'static_branch()' is inherently biased. That is, the > > 'false' path is assumed to be the the most likely path. Thus, the 'true' > > path is move out-of-line. Thus, if the 'true' branch is potentially > > used all the time, we would want to make sure that the savings of not > > having to check a variable is still worth it. I should probably rename > > static_branch() -> 'static_branch_default_false()' to make that clear. > > > Thank you for pointing out. > > My assumption is that it's disabled at boot by few people because sane > people will not config memcg if they don't want. Most of distro users > will not turn off it... I think that's a bad assumption. I see a lot of cgroup_disable=memory command lines, and _always_ add it to grub when installing "everything plus the kitchen sink" distro kernels on my boxen. -Mike