• Chen, Kenneth W's avatar
    [PATCH] remove hugetlb_clean_stale_pgtable() and fix huge_pte_alloc() · 0e5c9f39
    Chen, Kenneth W authored
    I don't think we need to call hugetlb_clean_stale_pgtable() anymore
    in 2.6.13 because of the rework with free_pgtables().  It now collect
    all the pte page at the time of munmap.  It used to only collect page
    table pages when entire one pgd can be freed and left with staled pte
    pages.  Not anymore with 2.6.13.  This function will never be called
    and We should turn it into a BUG_ON.
    I also spotted two problems here, not Adam's fault :-)
    (1) in huge_pte_alloc(), it looks like a bug to me that pud is not
        checked before calling pmd_alloc()
    (2) in hugetlb_clean_stale_pgtable(), it also missed a call to
        pmd_free_tlb.  I think a tlb flush is required to flush the mapping
        for the page table itself when we clear out the pmd pointing to a
        pte page.  However, since hugetlb_clean_stale_pgtable() is never
        called, so it won't trigger the bug.
    Signed-off-by: default avatarKen Chen <kenneth.w.chen@intel.com>
    Cc: Adam Litke <agl@us.ibm.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
hugetlb.h 5.03 KB