Date: Sun, 19 Aug 2007 12:38:27 +0400
From: Oleg Nesterov <oleg@tv-sign.ru>
To: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Gautham R Shenoy <ego@in.ibm.com>, Ingo Molnar <mingo@elte.hu>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel@vger.kernel.org
Subject: Re: [RFC,PATCH 5/5] exec: RT sub-thread can livelock and monopolize CPU on exec
Message-ID: <20070819083827.GA83@tv-sign.ru>
References: <20070818174001.GA218@tv-sign.ru> <20070818232525.9B7554D05C6@magilla.localdomain>
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On 08/18, Roland McGrath wrote:
>
> Maybe it can use wait_task_inactive, which IIUC is being changed to address
> the same RT issue.

The group_leader can sleep before it enters exit_notify(). In that case
wait_task_inactive() returns, and we still need some polling to wait for
EXIT_ZOMBIE.

> OTOH, notify_count exists only for this.  So maybe the
> better way is to clean that whole mechanism up somehow.

Yes sure. But in any case I think we should avoid polling, we need some
notification from exit_notify().

> The exit.c changes
> in your patch seem to be making it more mysterious rather than less so.

I completely agree.

Oleg.

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