From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753639AbYCUJyZ (ORCPT ); Fri, 21 Mar 2008 05:54:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754320AbYCUJyP (ORCPT ); Fri, 21 Mar 2008 05:54:15 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:34441 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754293AbYCUJyO (ORCPT ); Fri, 21 Mar 2008 05:54:14 -0400 Date: Fri, 21 Mar 2008 10:53:43 +0100 From: Ingo Molnar To: Jens Axboe Cc: linux-kernel@vger.kernel.org, npiggin@suse.de, paulus@samba.org, tglx@linutronix.de, mingo@redhat.com, tony.luck@intel.com Subject: Re: [PATCH 0/5] Generic smp_call_function(), improvements, and smp_call_function_single() Message-ID: <20080321095343.GA21409@elte.hu> References: <1205927772-31401-1-git-send-email-jens.axboe@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1205927772-31401-1-git-send-email-jens.axboe@oracle.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jens Axboe wrote: > The patch series is also available in the 'generic-ipi' branch from > > git://git.kernel.dk/linux-2.6-block.git > > and the 'io-cpu-affinity' branch is directly based on this. i'm still wondering about the following fundamental bit: why not use per CPU kernel threads? That way you get a fast (lockless) IPI "for free" as SMP wakeups already do this. smp_call_function() is quirky and has deep limitations on atomicity, etc., so we are moving away from it and should not base more functionality on it. Ingo