Messages in this thread | | | Date | Fri, 28 May 2010 10:59:47 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH] hugetlb: call mmu notifiers on hugepage cow |
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On Thu, May 27, 2010 at 01:43:00PM -0700, Doug Doan wrote: > From: Doug Doan <dougd@cray.com> > > When a copy-on-write occurs, we take one of two paths in handle_mm_fault: > through handle_pte_fault for normal pages, or through hugetlb_fault for > huge pages. > > In the normal page case, we eventually get to do_wp_page and call mmu > notifiers via ptep_clear_flush_notify. There is no callout to the mmmu > notifiers in the huge page case. This patch fixes that. > > Signed-off-by: Doug Doan <dougd@cray.com> > ---
> --- mm/hugetlb.c.orig 2010-05-27 13:07:58.569546314 -0700 > +++ mm/hugetlb.c 2010-05-26 14:41:06.449296524 -0700 > @@ -2345,11 +2345,17 @@ retry_avoidcopy: > ptep = huge_pte_offset(mm, address & huge_page_mask(h)); > if (likely(pte_same(huge_ptep_get(ptep), pte))) { > /* Break COW */ > + mmu_notifier_invalidate_range_start(mm, > + address & huge_page_mask(h), > + (address & huge_page_mask(h)) + huge_page_size(h));
Should the address not already be aligned?
Otherwise, I don't see any problem.
> huge_ptep_clear_flush(vma, address, ptep); > set_huge_pte_at(mm, address, ptep, > make_huge_pte(vma, new_page, 1)); > /* Make the old page be freed below */ > new_page = old_page; > + mmu_notifier_invalidate_range_end(mm, > + address & huge_page_mask(h), > + (address & huge_page_mask(h)) + huge_page_size(h)); > } > page_cache_release(new_page); > page_cache_release(old_page);
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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