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Cc: "Eric W. Biederman" <ebiederm@xmission.com>, linux-kernel@vger.kernel.org
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From: Kyle Moffett <mrmacman_g4@mac.com>
Subject: Re: anon unions are cool
Date: Tue, 24 Jan 2006 01:04:16 -0500
To: Albert Cahalan <acahalan@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
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On Jan 23, 2006, at 22:39, Albert Cahalan wrote:
>> Then there is the other weird side where only the leaders of
>> thread groups are placed in sessions and process groups.
>
> That's not at all weird. It fits perfectly with the use of the tgid  
> as the POSIX PID and the use of the "pid" (ugh) as the POSIX thread  
> ID.
>
> Aside from POSIX just being arguably weird, the only weird things  
> here are:
>
> 1. kill() not returning errno=ESRCH when it should
> 2. the name "pid" being used oddly in the kernel

And actually, my use of the task->pid member was correct.  The "pid  
virtualization" patches are virtualizing not only the process IDs,  
but the thread IDs as well (the whole point is to provide completely  
unique PID/TID spaces, so everything needs to be virtualized).  In  
any case, it was just a poorly chosen example (because that  
particular virtualization bit was not necessary).  I agree with you  
that the kernel's behavior is weird, but it has its reasons and a lot  
of history.  If you think it's that important, a cleanup patch  
(assuming it's not too intrusive) would probably be welcomed.

Cheers,
Kyle Moffett

--
I lost interest in "blade servers" when I found they didn't throw  
knives at people who weren't supposed to be in your machine room.
   -- Anthony de Boer


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