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Subject: Re: [PATCH] Per-task watchers: Enable inheritance
From: Matt Helsley <matthltc@us.ibm.com>
To: "John T. Kohl" <jtk@us.ibm.com>
Cc: Andrew Morton <akpm@osdl.org>, Peter Williams <pwil3058@bigpond.net.au>,
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Date: Fri, 23 Jun 2006 16:33:04 -0700
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On Fri, 2006-06-23 at 17:17 -0400, John T. Kohl wrote:
> >>>>> "MattH" ==   <matthltc@us.ibm.com> writes:
> 
> MattH> This allows per-task watchers to implement inheritance of the
> MattH> same function and/or data in response to the initialization of
> MattH> new tasks. A watcher might implement inheritance using the
> MattH> following notifier_call snippet:
> 
> I think this would meet our needs--we (MVFS) need to initialize some new
> state in a child process based on our state in the parent process
> (essentially, module-private inherited per-process state).  It may still
> be a bit clumsy to find the per-process state in other situations,
> though.  While a process is executing our module's code, would it be
> safe to traverse current's notifier chain to find our state?

	Hmm. We may need to be careful with terminology here. Keep in mind that
a task is not the same as the userspace concept of a  "process".

	When a task is executing a module's code it will be safe to traverse
the task's notifier chain to find state. It will *not* be safe to
traverse the notifier chain of other tasks -- even if the other task is
a thread in the same "process".

Cheers,
	-Matt Helsley