Re: [RFC][PATCH 0/5] VM_PINNED

From: Christoph Lameter
Date: Tue May 27 2014 - 12:31:32 EST


On Tue, 27 May 2014, Peter Zijlstra wrote:

> On Tue, May 27, 2014 at 10:14:10AM -0500, Christoph Lameter wrote:
> > On Tue, 27 May 2014, Peter Zijlstra wrote:
> >
> > > Well, like with IB, they start out as normal userspace pages, and will
> > > be from ZONE_MOVABLE.
> >
> > Well we could change that now I think. If the VMA has VM_PINNED set
> > pages then do not allocate from ZONE_MOVABLE.
>
> But most allocations sites don't have the vma. We allocate page-cache
> pages based on its address_space/mapping, not on whatever vma they're
> mapped into.

Most allocations by the application for an address range also must
consider a memory allocation policy which is also bound to a vma and we
have code for that in mm/mempolicy.c

Code could be easily added to alloc_pages_vma() to consider the pinned
status on allocation. Remove GFP_MOVABLE if the vma is pinned.

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