From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965133AbbI2Nlo (ORCPT ); Tue, 29 Sep 2015 09:41:44 -0400 Received: from mail-wi0-f181.google.com ([209.85.212.181]:35051 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965166AbbI2Nl3 (ORCPT ); Tue, 29 Sep 2015 09:41:29 -0400 Date: Tue, 29 Sep 2015 15:41:26 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, oleg@redhat.com, umgwanakikbuti@gmail.com, tglx@linutronix.de, rostedt@goodmis.org Subject: Re: [RFC][PATCH 04/11] sched: Rework TASK_DEAD preemption exception Message-ID: <20150929134125.GF31582@lerouge> References: <20150929092825.540553633@infradead.org> <20150929093520.037072067@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150929093520.037072067@infradead.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 29, 2015 at 11:28:29AM +0200, Peter Zijlstra wrote: > TASK_DEAD is special in that the final schedule call from do_exit() > must be done with preemption disabled. > > This leads to a violation of our new scheduling invariant which states > that the preempt count should be 2. Move the check for TASK_DEAD out > of the debug check and use it to decrement the preempt count (from 2 > to 1). > > Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Frederic Weisbecker