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Date: Mon, 5 May 2003 19:58:44 -0400 (EDT)
From: Daniel Eischen <eischen@pcnet1.pcnet.com>
To: Julian Elischer <julian@elischer.org>
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cc: threads@freebsd.org
Subject: Re: kern_threads.c..  upcall question..
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On Mon, 5 May 2003, Julian Elischer wrote:

> 
> In kern_threads.c, in function thread_export_context()
> it first does a copyin() of the
> context storage area. I think this is un-needed (and a complete waste of
> cycles) but I am not sure if there is some strange condition
> regarding floating point registers or something that may want this..
> 
> Dan, Jon, David?
> do any of you have a good reason why I shouldn't remove the copyin().??

Yeah, the threads library keeps the thread's active signal
mask in the context area.  The stack and flags may also
be used in the context.

You should be able to safely copy out the mcontext without
a copyin().  Is that what you're currently doing?  Or is
the entire context (ucontext) being exported?

-- 
Dan Eischen