Messages in this thread | | | Date | Fri, 3 Mar 2006 05:18:51 +0000 (GMT) | From | Hugh Dickins <> | Subject | Re: hugepage: Fix hugepage logic in free_pgtables() harder |
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On Fri, 3 Mar 2006, 'David Gibson' wrote:
> Sigh. Turns out the hugepage logic in free_pgtables() was doubly > broken. The loop coalescing multiple normal page VMAs into one call > to free_pgd_range() had an off by one error, which could mean it would > coalesce one hugepage VMA into the same bundle (checking 'vma' not > 'next' in the loop). I transferred this bug into the new > is_vm_hugetlb_page() based version. Here's the fix. > > This one didn't bite on powerpc previously for the same reason the > is_hugepage_only_range() problem didn't: powerpc's > hugetlb_free_pgd_range() is identical to free_pgd_range(). It didn't > bite on ia64 because the hugepage region is distant enough from any > other region that the separated PMD_SIZE distance test would always > prevent coalescing the two together.
I agree with your patch, but not with your comment: it's just a fix to your earlier patch, there's no such off-by-one in the mainline free_pgtables. Probably you were misled by my use of "vma->vm_mm" rather than "next->vm_mm", equal but admittedly confusing, when looking at the "next" vma.
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