Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758471AbcDESC4 (ORCPT ); Tue, 5 Apr 2016 14:02:56 -0400 Received: from casper.infradead.org ([85.118.1.10]:43599 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752172AbcDESCz (ORCPT ); Tue, 5 Apr 2016 14:02:55 -0400 Date: Tue, 5 Apr 2016 20:02:52 +0200 From: Peter Zijlstra To: luca abeni Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Juri Lelli Subject: Re: [RFC v2 3/7] Improve the tracking of active utilisation Message-ID: <20160405180252.GP3408@twins.programming.kicks-ass.net> References: <1459523553-29089-1-git-send-email-luca.abeni@unitn.it> <1459523553-29089-4-git-send-email-luca.abeni@unitn.it> <20160405150036.GA3430@twins.programming.kicks-ass.net> <20160405195657.586e8c97@utopia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160405195657.586e8c97@utopia> 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: 648 Lines: 15 On Tue, Apr 05, 2016 at 07:56:57PM +0200, luca abeni wrote: > > > + migrate_active = hrtimer_active(&p->dl.inactive_timer); > > > + if (migrate_active) > > > + sub_running_bw(&p->dl, &rq->dl); > > > + raw_spin_unlock(&rq->lock); > > > > At this point task_rq() is still the above rq, so if the inactive timer > > hits here it will lock this rq and subtract the running bw here _again_, > > right? > I think it will see the task state as TASK_RUNNING, so it will do nothing. > Or it will cancelled later when the task is enqueued... I'll double check this. Right, so this is select_task_rq_dl(), we run this in wakeups, before TASK_RUNNING.