Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752981Ab2JVKme (ORCPT ); Mon, 22 Oct 2012 06:42:34 -0400 Received: from casper.infradead.org ([85.118.1.10]:50860 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752308Ab2JVKmd convert rfc822-to-8bit (ORCPT ); Mon, 22 Oct 2012 06:42:33 -0400 Message-ID: <1350902505.2768.88.camel@twins> Subject: Re: [RFC PATCH 5/8] irq_work: Make self-IPIs optable From: Peter Zijlstra To: Frederic Weisbecker Cc: LKML , Thomas Gleixner , Ingo Molnar , Andrew Morton , Steven Rostedt , Paul Gortmaker Date: Mon, 22 Oct 2012 12:41:45 +0200 In-Reply-To: <1350750167-14263-6-git-send-email-fweisbec@gmail.com> References: <1350750167-14263-1-git-send-email-fweisbec@gmail.com> <1350750167-14263-6-git-send-email-fweisbec@gmail.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1009 Lines: 24 On Sat, 2012-10-20 at 12:22 -0400, Frederic Weisbecker wrote: > + if (empty) { > + /* > + * If an IPI is requested, raise it right away. Otherwise wait > + * for the next tick unless it's stopped. Now if the arch uses > + * some other obscure way than IPI to raise an irq work, just raise > + * and don't think further. > + */ > + if (ipi || !arch_irq_work_has_ipi() || tick_nohz_tick_stopped()) > + arch_irq_work_raise(); > + } > preempt_enable(); > } Doesn't this have a problem where we enqueue the first lazy and then one with ipi? In that case it appears we won't send the IPI because the queue wasn't empty. -- 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/