From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759371AbYDYHSi (ORCPT ); Fri, 25 Apr 2008 03:18:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753518AbYDYHS3 (ORCPT ); Fri, 25 Apr 2008 03:18:29 -0400 Received: from brick.kernel.dk ([87.55.233.238]:26638 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751571AbYDYHS3 (ORCPT ); Fri, 25 Apr 2008 03:18:29 -0400 Date: Fri, 25 Apr 2008 09:18:24 +0200 From: Jens Axboe To: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, npiggin@suse.de, torvalds@linux-foundation.org, peterz@infradead.org, sam@ravnborg.org Subject: Re: [PATCH 1/11] Add generic helpers for arch IPI function calls Message-ID: <20080425071823.GF12774@kernel.dk> References: <1208890227-24808-1-git-send-email-jens.axboe@oracle.com> <1208890227-24808-2-git-send-email-jens.axboe@oracle.com> <20080424220157.GA26179@flint.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080424220157.GA26179@flint.arm.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 24 2008, Russell King wrote: > On Tue, Apr 22, 2008 at 08:50:17PM +0200, Jens Axboe wrote: > > + data->csd.func(data->csd.info); > > + > > + spin_lock(&data->lock); > > + cpu_clear(cpu, data->cpumask); > > + WARN_ON(data->refs == 0); > > + data->refs--; > > + refs = data->refs; > > Probably a silly question, but what does data->refs do that > cpus_empty(data->cpumask) wouldn't do? (as indeed ARM presently does.) I guess it can be marginally slower for NR_CPUS > BITS_PER_LONG, otherwise there's absolutely no reason to have a seperate ref counter. -- Jens Axboe