linux-kernel - Re: Doubt about push_dl_task() / find_lock_later

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Date:   Thu, 5 Jan 2017 13:19:26 +0100
From:   luca abeni <luca.abeni@...tn.it>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org, Juri Lelli <juri.lelli@....com>,
        Daniel Bristot de Oliveira <bristot@...hat.com>
Subject: Re: Doubt about push_dl_task() / find_lock_later_rq()

On Thu, 5 Jan 2017 12:48:38 +0100
Peter Zijlstra <peterz@...radead.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