From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933197AbaEEO6X (ORCPT ); Mon, 5 May 2014 10:58:23 -0400 Received: from casper.infradead.org ([85.118.1.10]:55849 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933011AbaEEO6U convert rfc822-to-8bit (ORCPT ); Mon, 5 May 2014 10:58:20 -0400 Date: Mon, 5 May 2014 16:58:15 +0200 From: Peter Zijlstra To: Frederic Weisbecker 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: <20140505145815.GQ26782@laptop.programming.kicks-ass.net> References: <20140505123706.GP17778@laptop.programming.kicks-ass.net> <20140505145256.GA2099@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <20140505145256.GA2099@localhost.localdomain> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.