tree a81434613acbfe4aeea6416c9274f9b18d9d9ddc
parent 4e90b688013526340fef9f11ae0184888fd563d1
author Mike Kravetz <mike.kravetz@oracle.com> 1468613322 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1479719200 +0100

sparc64 mm: Fix base TSB sizing when hugetlb pages are used

[ Upstream commit af1b1a9b36b8f9d583d4b4f90dd8946ed0cd4bd0 ]

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: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>