Re: [patch 1/3] mmu_notifier: Core code

[Christoph Lameter]

On Thu, 31 Jan 2008, Robin Holt wrote:

> Both xpmem and GRU have means of removing their context seperate from
> process termination.  XPMEMs is by closing the fd, I believe GRU is
> the same.  In the case of XPMEM, we are able to acquire the mmap_sem.
> For GRU, I don't think it is possible, but I do not remember the exact
> reason.

For any action initiated from user space you will not hold mmap sem. So 
you can call the unregister function. Then you need to do a 
synchronize_rcu before freeing the structures.

It is also possible to shut this down outside via f.e. a control thread. 
The control thread can acquire mmap_sem and then unregister the notifier.

Am I missing something?

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