Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753462Ab0HYUB5 (ORCPT ); Wed, 25 Aug 2010 16:01:57 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:35759 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752469Ab0HYUBz convert rfc822-to-8bit (ORCPT ); Wed, 25 Aug 2010 16:01:55 -0400 MIME-Version: 1.0 In-Reply-To: <20100825132815.108d8217@bike.lwn.net> References: <20100825132815.108d8217@bike.lwn.net> From: Linus Torvalds Date: Wed, 25 Aug 2010 13:00:59 -0700 Message-ID: Subject: Re: [PATCH] lglock: make lg_lock_global() actually lock globally To: Jonathan Corbet , Tejun Heo , Peter Zijlstra , Rusty Russell Cc: Al Viro , Nick Piggin , LKML Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1110 Lines: 25 On Wed, Aug 25, 2010 at 12:28 PM, Jonathan Corbet wrote: > lglock: make lg_lock_global() actually lock globally Grrr. Same disease as Nick and others. Why do you repeat the subject line in the body? Don't do that. We don't want the summary line twice in the commit message, and we don't want it twice in the email. We simply don't want it twice. Full stop. > lg_lock_global() currently only acquires spinlocks for online CPUs, but > it's meant to lock all possible CPUs. ?At Nick's suggestion, change > for_each_online_cpu() to for_each_possible_cpu() to get the expected > behavior. Can you say what this actually matters for? Don't we do stop-machine for CPU hotplug anyway? And if we don't, shouldn't we? Exactly because otherwise "for_each_online_cpu()" is always racy (and that has nothing to do with the lglock). 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/