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  • Mike Kravetz's avatar
    sparc64 mm: Fix base TSB sizing when hugetlb pages are used · af1b1a9b
    Mike Kravetz authored
    do_sparc64_fault() calculates both the base and huge page RSS sizes and
    uses this information in calls to tsb_grow().  The calculation for base
    page TSB size is not correct if the task uses hugetlb pages.  hugetlb
    pages are not accounted for in RSS, therefore the call to get_mm_rss(mm)
    does not include hugetlb pages.  However, the number of pages based on
    huge_pte_count (which does include hugetlb pages) is subtracted from
    this value.  This will result in an artificially small and often negative
    RSS calculation.  The base TSB size is then often set to max_tsb_size
    as the passed RSS is unsigned, so a negative value looks really big.
    THP pages are also accounted for in huge_pte_count, and THP pages are
    accounted for in RSS so the calculation in do_sparc64_fault() is correct
    if a task only uses THP pages.
    A single huge_pte_count is not sufficient for TSB sizing if both hugetlb
    and THP pages can be used.  Instead of a single counter, use two:  one
    for hugetlb and one for THP.
    Signed-off-by: default avatarMike Kravetz <>
    Signed-off-by: default avatarDavid S. Miller <>