Date: Wed, 27 Feb 2008 14:11:19 -0800 (PST)
From: Christoph Lameter <clameter@sgi.com>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
cc: Pete Wyckoff <pw@osc.edu>, Rik van Riel <riel@redhat.com>,
       Andrea Arcangeli <andrea@qumranet.com>, a.p.zijlstra@chello.nl,
       izike@qumranet.com, Roland Dreier <rdreier@cisco.com>, steiner@sgi.com,
       linux-kernel@vger.kernel.org, avi@qumranet.com, linux-mm@kvack.org,
       daniel.blueman@quadrics.com, Robin Holt <holt@sgi.com>,
       general@lists.openfabrics.org,
       Andrew Morton <akpm@linux-foundation.org>,
       kvm-devel@lists.sourceforge.net
Subject: Re: [ofa-general] Re: Demand paging for memory regions
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On Wed, 13 Feb 2008, Jason Gunthorpe wrote:

> Christoph: It seemed to me you were first talking about
> freeing/swapping/faulting RDMA'able pages - but would pure migration
> as a special hardware supported case be useful like Catilan suggested?

That is a special case of the proposed solution. You could mlock the 
regions of interest. Those can then only be migrated but not swapped out.

However, I think we need some limit on the number of pages one can mlock. 
Otherwise the VM can get into a situation where reclaim is not possible 
because the majority of memory is either mlocked or pinned by I/O etc.

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