Re: CLONE_KILLVMCH flag proposal

[Alon Ziv]

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Indeed, it is possible to just use the 'parent death' signal from prctl()
for this purpose.
Once (not so long ago...), when Tim Wragg was working on pthread
enhancements,
we tried out a (tricky) method which made the manager thread the parent of
all
other threads in the process (including the main thread); after this, if the
manager
failed, other threads got a signal (which they invited via prctl()) and
died.

----- Original Message -----
From: Richard Gooch <[e-mail]>
To: Pavel Krauz <[e-mail]>
Cc: <[e-mail]>; <[e-mail]>
Sent: Tuesday, February 15, 2000 21:38
Subject: Re: CLONE_KILLVMCH flag proposal

> Pavel Krauz writes:
> > Hello
> >
> > I am trying to modify pthread library a way in which it  would not
> > need manager thread. It seems that it is pretty feasible with
> > CLONE_PARENT but one thing is missing.
> >
> > If the main thread dies due to some fatal error other threads will live
> > further. This problem is not easily solved without manager thread so
> > kernel will have to help here.
> >
> > This is an proposal for CLONE_KILLVMCH. The process/thread that
> > has this flag set will kill all its children that share the same VM
> > (were created with CLONE_VM) when it dies.
> > This way the main thread will clean threads when some fatal error
> > or kill occurs that cannot be caught in user space.
> > I think that this is the only obstacle to make pthread support without
> > manager thread and thus solve performance problems with creating and
> > managing threads.
> >
> > Any ideas are highly appreciated.
> >
> > Here goes the patch that implement CLONE_KILLVMCH. I think it is not
> > perfect but consider something like this as addition to the kernel.
>
> How about looking at prctl(2), which was added for just this purpose?
>
> Regards,
>
> Richard....
> Old:     [e-mail]
> Current: [e-mail]
>
> -
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>

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