From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933208AbaEEPGL (ORCPT ); Mon, 5 May 2014 11:06:11 -0400 Received: from mail-wg0-f52.google.com ([74.125.82.52]:46520 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933011AbaEEPGJ (ORCPT ); Mon, 5 May 2014 11:06:09 -0400 Date: Mon, 5 May 2014 17:06:01 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, hpa@zytor.com, paulmck@linux.vnet.ibm.com, akpm@linux-foundation.org, khilman@linaro.org, tglx@linutronix.de, axboe@fb.com, linux-tip-commits@vger.kernel.org Subject: Re: [tip:timers/nohz] nohz: Move full nohz kick to its own IPI Message-ID: <20140505150558.GC2099@localhost.localdomain> References: <20140505123706.GP17778@laptop.programming.kicks-ass.net> <20140505145256.GA2099@localhost.localdomain> <20140505145815.GQ26782@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140505145815.GQ26782@laptop.programming.kicks-ass.net> 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 On Mon, May 05, 2014 at 04:58:15PM +0200, Peter Zijlstra wrote: > On Mon, May 05, 2014 at 04:52:59PM +0200, Frederic Weisbecker wrote: > > > Should we instead do irq_work_queue_on() ? > > > > I would really much prefer that yeah. But if we do that, expect some added overhead on the local > > irq_work_queue() path though. irq_work_raise can't use local cmpxchg ops anymore. > > > > Or we can have a different pending raise system for remote irq work. > > > > I can try something. > > Loosing that local cmpxchg shouldn't be a problem, I don't thnk this is > a particularly hot path. Then the conversion is easy since most of the irq work code should already work for remote queuing. I'll come up with a patch soon. Thanks.