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| author | Zi Yan <zi.yan@cs.rutgers.edu> | 2017-09-08 16:11:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-08 18:26:45 -0700 |
| commit | 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 (patch) | |
| tree | fc028524f9272c5ba1690d18937ebfc0bf0a0f9e /mm/mremap.c | |
| parent | 616b8371539a6c487404c3b8fb04078016dab4ba (diff) | |
| download | lwn-84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3.tar.gz lwn-84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3.zip | |
mm: thp: check pmd migration entry in common path
When THP migration is being used, memory management code needs to handle
pmd migration entries properly. This patch uses !pmd_present() or
is_swap_pmd() (depending on whether pmd_none() needs separate code or
not) to check pmd migration entries at the places where a pmd entry is
present.
Since pmd-related code uses split_huge_page(), split_huge_pmd(),
pmd_trans_huge(), pmd_trans_unstable(), or
pmd_none_or_trans_huge_or_clear_bad(), this patch:
1. adds pmd migration entry split code in split_huge_pmd(),
2. takes care of pmd migration entries whenever pmd_trans_huge() is present,
3. makes pmd_none_or_trans_huge_or_clear_bad() pmd migration entry aware.
Since split_huge_page() uses split_huge_pmd() and pmd_trans_unstable()
is equivalent to pmd_none_or_trans_huge_or_clear_bad(), we do not change
them.
Until this commit, a pmd entry should be:
1. pointing to a pte page,
2. is_swap_pmd(),
3. pmd_trans_huge(),
4. pmd_devmap(), or
5. pmd_none().
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mremap.c')
| -rw-r--r-- | mm/mremap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 7395564daa6c..cfec004c4ff9 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -223,7 +223,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma, new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr); if (!new_pmd) break; - if (pmd_trans_huge(*old_pmd)) { + if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) { if (extent == HPAGE_PMD_SIZE) { bool moved; /* See comment in move_ptes() */ |