lkml.org 
[lkml]   [2013]   [Dec]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 12/18] mm: numa: Defer TLB flush for THP migration as long as possible
    Date
    THP migration can fail for a variety of reasons. Avoid flushing the TLB
    to deal with THP migration races until the copy is ready to start.

    Cc: stable@vger.kernel.org
    Signed-off-by: Mel Gorman <mgorman@suse.de>
    ---
    mm/huge_memory.c | 7 -------
    mm/migrate.c | 6 ++++++
    2 files changed, 6 insertions(+), 7 deletions(-)

    diff --git a/mm/huge_memory.c b/mm/huge_memory.c
    index e3a5ee2..e3b6a75 100644
    --- a/mm/huge_memory.c
    +++ b/mm/huge_memory.c
    @@ -1377,13 +1377,6 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
    }

    /*
    - * The page_table_lock above provides a memory barrier
    - * with change_protection_range.
    - */
    - if (tlb_flush_pending(mm))
    - flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);
    -
    - /*
    * Migrate the THP to the requested node, returns with page unlocked
    * and pmd_numa cleared.
    */
    diff --git a/mm/migrate.c b/mm/migrate.c
    index cfb4190..5372521 100644
    --- a/mm/migrate.c
    +++ b/mm/migrate.c
    @@ -1759,6 +1759,12 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
    goto out_fail;
    }

    + /* PTL provides a memory barrier with change_protection_range */
    + ptl = pmd_lock(mm, pmd);
    + if (tlb_flush_pending(mm))
    + flush_tlb_range(vma, mmun_start, mmun_end);
    + spin_unlock(ptl);
    +
    /* Prepare a page as a migration target */
    __set_page_locked(new_page);
    SetPageSwapBacked(new_page);
    --
    1.8.4


    \
     
     \ /
      Last update: 2013-12-09 08:41    [W:3.287 / U:0.136 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site