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authorDan Williams <dan.j.williams@intel.com>2016-01-15 16:56:52 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 17:56:32 -0800
commit5c7fb56e5e3f7035dd798a8e1adee639f87043e5 (patch)
treee3419de32c4b42c918267a50120549cbec2ed63f /mm/pgtable-generic.c
parent5c2c2587b13235bf8b5c9027589f22eff68bdf49 (diff)
downloadlinux-5c7fb56e5e3f7035dd798a8e1adee639f87043e5.tar.bz2
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 <dan.j.williams@intel.com> Cc: Dave Hansen <dave@sr71.net> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/pgtable-generic.c')
-rw-r--r--mm/pgtable-generic.c2
1 files changed, 1 insertions, 1 deletions
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;