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@xxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxx> --- 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>