Date: Mon, 6 Aug 2007 20:50:07 +0400
From: Oleg Nesterov <oleg@tv-sign.ru>
To: Gregory Haskins <ghaskins@novell.com>
Cc: Daniel Walker <dwalker@mvista.com>, Peter Zijlstra <peterz@infradead.org>,
       Ingo Molnar <mingo@elte.hu>, linux-rt-users@vger.kernel.org,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RT: Add priority-queuing and priority-inheritance to workqueue infrastructure
Message-ID: <20070806165007.GB4021@tv-sign.ru>
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On 08/06, Gregory Haskins wrote:
>
> On Mon, 2007-08-06 at 19:36 +0400, Oleg Nesterov wrote:
> 
> > > E.g. whatever work was being flushed was allowed to escape
> > > out from behind the barrier.  If you don't care about the flush working,
> > > why do it at all?
> > 
> > The caller of flush_workueue() doesn't necessary know we have such a work
> > on list. It just wants to flush its own works.
> 
> I was assuming that the work being flushed was submitted by the same
> context, but I think I see what you are saying now.  Essentially if that
> queued work was unrelated to the thread that was doing the flush, it
> doesn't care if it gets rescheduled.

Yes.

> Do you agree that if the context was the same there is a bug?  Or did I
> miss something else?

Yes sure. We can't expect we can "flush" work_struct with flush_workqueue()
unless we know it doesn't re-schedule itself.

OTOH, it is not the bug to call flush_workqueue() even if that work was
queued by us, it should complete.

Oleg.

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