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Date: Wed, 2 Apr 2008 15:41:34 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
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To: Andrea Arcangeli <andrea@qumranet.com>
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       daniel.blueman@quadrics.com, Nick Piggin <npiggin@suse.de>
Subject: Re: EMM: Require single threadedness for registration.
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On Thu, 3 Apr 2008, Andrea Arcangeli wrote:

> Why can't it fire on the mm_struct where GRU just registered? That
> mm_struct existed way before GRU registered, and VM is free to unmap
> it w/o mmap_sem if there was any memory pressure.

Right. Hmmm... Bad situation. We would have invalidate_start take
a lock to prevent registration until _end has run.

We could use stop_machine_run to register the notifier.... ;-).