Messages in this thread | | | Date | Wed, 30 Jan 2008 14:29:18 -0600 | From | Jack Steiner <> | Subject | Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges |
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On Wed, Jan 30, 2008 at 11:41:29AM -0800, Christoph Lameter wrote: > On Wed, 30 Jan 2008, Jack Steiner wrote: > > > I see what you mean. I need to review to mail to see why this changed > > but in the original discussions with Christoph, the invalidate_range > > callouts were suppose to be made BEFORE the pages were put on the freelist. > > Seems that we cannot rely on the invalidate_ranges for correctness at all? > We need to have invalidate_page() always. invalidate_range() is only an > optimization. >
I don't understand your point "an optimization". How would invalidate_range as currently defined be correctly used?
It _looks_ like it would work only if xpmem/gru/etc takes a refcnt on the page & drops it when invalidate_range is called. That may work (not sure) for xpmem but not for the GRU.
--- jack
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