From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1762682AbdAEMUi (ORCPT <rfc822;w@1wt.eu>);
        Thu, 5 Jan 2017 07:20:38 -0500
Received: from mail-wj0-f182.google.com ([209.85.210.182]:36356 "EHLO
        mail-wj0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S938502AbdAEMUa (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 5 Jan 2017 07:20:30 -0500
Date: Thu, 5 Jan 2017 13:19:26 +0100
From: luca abeni <luca.abeni@unitn.it>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Juri Lelli <juri.lelli@arm.com>,
        Daniel Bristot de Oliveira <bristot@redhat.com>
Subject: Re: Doubt about push_dl_task() / find_lock_later_rq()
Message-ID: <20170105131926.52b5fe37@sweethome>
In-Reply-To: <20170105114838.GJ3093@worktop>
References: <20170104154935.7f08d550@sweethome>
        <20170105082923.639adcf9@sweethome>
        <20170105114838.GJ3093@worktop>
Organization: university of trento
X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, 5 Jan 2017 12:48:38 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Jan 05, 2017 at 08:29:23AM +0100, luca abeni wrote:
[...]
> > I was confused by the fact that in some cases I saw
> > rq->dl.earliest_dl.curr != rq->curr->dl.deadline
> > 
> > I still do not understand how this can happen (I am not changing
> > tasks affinities), and I am investigating this.  
> 
> 
> I'm having trouble spotting code that does that...

I think I might have found the issue (switched_to_dl() adjusting the
task's deadline without dequeueing/re-enqueueing it)... I am working on
a patch, and I'll send it this afternoon.


			Thanks,
				Luca