Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753484AbbHCNE5 (ORCPT ); Mon, 3 Aug 2015 09:04:57 -0400 Received: from casper.infradead.org ([85.118.1.10]:48418 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751982AbbHCNE4 (ORCPT ); Mon, 3 Aug 2015 09:04:56 -0400 Date: Mon, 3 Aug 2015 15:04:50 +0200 From: Peter Zijlstra To: Frederic Weisbecker Cc: LKML , Thomas Gleixner , Preeti U Murthy , Christoph Lameter , Ingo Molnar , Viresh Kumar , Rik van Riel Subject: Re: [PATCH 04/10] nohz: Remove useless argument on tick_nohz_task_switch() Message-ID: <20150803130450.GN25159@twins.programming.kicks-ass.net> References: <1437669735-8786-1-git-send-email-fweisbec@gmail.com> <1437669735-8786-5-git-send-email-fweisbec@gmail.com> <20150803123959.GG19282@twins.programming.kicks-ass.net> <20150803124952.GB20269@lerouge> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150803124952.GB20269@lerouge> 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 Content-Length: 1246 Lines: 33 On Mon, Aug 03, 2015 at 02:49:54PM +0200, Frederic Weisbecker wrote: > On Mon, Aug 03, 2015 at 02:39:59PM +0200, Peter Zijlstra wrote: > > On Thu, Jul 23, 2015 at 06:42:09PM +0200, Frederic Weisbecker wrote: > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > > index 78b4bad10..4d34035 100644 > > > --- a/kernel/sched/core.c > > > +++ b/kernel/sched/core.c > > > @@ -2489,7 +2489,7 @@ static struct rq *finish_task_switch(struct task_struct *prev) > > > put_task_struct(prev); > > > } > > > > > > - tick_nohz_task_switch(current); > > > + tick_nohz_task_switch(); > > > return rq; > > > } > > > > OK, so I just noticed this one. Please explain? WTF does it make sense > > to have per task tick state? > > > > If we have >1 tasks, we need the tick. If we have 1 task, per-task == > > per-cpu. > > > > So what gives? > > tick_nohz_task_switch() is removed in the end of the patchset. There is no > more per task dependency after this specific set. OK, I'll keep reading ;-) -- 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/