Date: Wed, 27 Feb 2008 14:23:29 -0800 (PST)
From: Christoph Lameter <clameter@sgi.com>
To: Andrea Arcangeli <andrea@qumranet.com>
cc: Nick Piggin <nickpiggin@yahoo.com.au>, akpm@linux-foundation.org,
       Robin Holt <holt@sgi.com>, Avi Kivity <avi@qumranet.com>,
       Izik Eidus <izike@qumranet.com>, kvm-devel@lists.sourceforge.net,
       Peter Zijlstra <a.p.zijlstra@chello.nl>, general@lists.openfabrics.org,
       Steve Wise <swise@opengridcomputing.com>,
       Roland Dreier <rdreier@cisco.com>, Kanoj Sarcar <kanojsarcar@yahoo.com>,
       steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
       daniel.blueman@quadrics.com
Subject: Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges
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On Tue, 19 Feb 2008, Andrea Arcangeli wrote:

> Yes, that's why I kept maintaining my patch and I posted the last
> revision to Andrew. I use pte/tlb locking of the core VM, it's
> unintrusive and obviously safe. Furthermore it can be extended with
> Christoph's stuff in a 100% backwards compatible fashion later if needed.

How would that work? You rely on the pte locking. Thus calls are all in an 
atomic context. I think we need a general scheme that allows sleeping when 
references are invalidates. Even the GRU has performance issues when using 
the KVM patch.


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