From 5c7fb56e5e3f7035dd798a8e1adee639f87043e5 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 15 Jan 2016 16:56:52 -0800 Subject: mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd A dax-huge-page mapping while it uses some thp helpers is ultimately not a transparent huge page. The distinction is especially important in the get_user_pages() path. pmd_devmap() is used to distinguish dax-pmds from pmd_huge() and pmd_trans_huge() which have slightly different semantics. Explicitly mark the pmd_trans_huge() helpers that dax needs by adding pmd_devmap() checks. [kirill.shutemov@linux.intel.com: fix regression in handling mlocked pages in __split_huge_pmd()] Signed-off-by: Dan Williams Cc: Dave Hansen Cc: Mel Gorman Cc: Peter Zijlstra Cc: Andrea Arcangeli Cc: Matthew Wilcox Signed-off-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/pgtable-generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/pgtable-generic.c') diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c index c311a2ec6fea..9d4767698a1c 100644 --- a/mm/pgtable-generic.c +++ b/mm/pgtable-generic.c @@ -132,7 +132,7 @@ pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address, { pmd_t pmd; VM_BUG_ON(address & ~HPAGE_PMD_MASK); - VM_BUG_ON(!pmd_trans_huge(*pmdp)); + VM_BUG_ON(!pmd_trans_huge(*pmdp) && !pmd_devmap(*pmdp)); pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp); flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); return pmd; -- cgit v1.2.3-55-g7522