Re: [ofa-general] Re: Demand paging for memory regions

From: Christoph Lameter
Date: Wed Feb 27 2008 - 17:11:38 EST


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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