Messages in this thread | | | Date | Wed, 2 Apr 2008 15:06:19 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: EMM: Require single threadedness for registration. |
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On Thu, 3 Apr 2008, Andrea Arcangeli wrote:
> That would work for #v10 if I remove the invalidate_range_start from > try_to_unmap_cluster, it can't work for EMM because you've > emm_invalidate_start firing anywhere outside the context of the > current task (even regular rmap code, not just nonlinear corner case > will trigger the race). In short the single threaded approach would be
But in that case it will be firing for a callback to another mm_struct. The notifiers are bound to mm_structs and keep separate contexts.
> The requirement for invalidate_page is that the pte and linux tlb are > flushed _before_ and the page is freed _after_ the invalidate_page > method. that's not the case for _begin/_end. The page is freed well > before _end runs, hence the need of _begin and to block the secondary > mmu page fault during the vma-mangling operations.
You could flush in _begin and free on _end? I thought you are taking a refcount on the page? You can drop the refcount only on _end to ensure that the page does not go away before.
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