From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757716AbaHGNSr (ORCPT ); Thu, 7 Aug 2014 09:18:47 -0400 Received: from mail-wg0-f47.google.com ([74.125.82.47]:60496 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754910AbaHGNSp (ORCPT ); Thu, 7 Aug 2014 09:18:45 -0400 Date: Thu, 7 Aug 2014 15:18:42 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: Dave Jones , Linux Kernel Subject: Re: WARN_ON_ONCE(in_nmi()) hit in irq_work_queue_on Message-ID: <20140807131840.GC19662@localhost.localdomain> References: <20140806162113.GC14261@redhat.com> <20140806164633.GY3935@laptop> <20140806165610.GB12054@laptop.lan> <20140806170151.GC12054@laptop.lan> <20140806234456.GA17015@localhost.localdomain> <20140807081321.GI19379@twins.programming.kicks-ass.net> <20140807125852.GA19662@localhost.localdomain> <20140807131536.GU9918@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140807131536.GU9918@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 07, 2014 at 03:15:36PM +0200, Peter Zijlstra wrote: > On Thu, Aug 07, 2014 at 02:58:55PM +0200, Frederic Weisbecker wrote: > > On Thu, Aug 07, 2014 at 10:13:21AM +0200, Peter Zijlstra wrote: > > > On Thu, Aug 07, 2014 at 01:44:58AM +0200, Frederic Weisbecker wrote: > > > > In fact the problem has arised since the recent irq work patches I did. > > > > > > No, those just added the WARN, previously we send the resched IPI, and > > > that's equally wrong from NMI context. > > > > Well the scheduler IPI was rather used for remote kicks before we had remote irq > > work. This includes local kicks as well as the caller could need to kick > > anywhere. As in inc_nr_running(). > > > > But for strict local kicks, as in perf, we were using tick_nohz_full_kick() which has > > been using irq work for a while. But it got broken when we replaced it to call irq_work_queue_on > > instead of irq_work_queue. > > OK, clearly I made a mess of things in my head ;-) I'm a bit responsible for that mess since I created quite some flavours of nohz kicks all around :) But now they should be more unified.