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| author |   Dan Williams <dan.j.williams@intel.com> | 2016-01-15 16:56:52 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-15 17:56:32 -0800 |
| commit | 5c7fb56e5e3f7035dd798a8e1adee639f87043e5 (patch) | |
| tree | e3419de32c4b42c918267a50120549cbec2ed63f /include/linux/huge_mm.h | |
| parent | mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup (diff) | |
| download | linux-dev-5c7fb56e5e3f7035dd798a8e1adee639f87043e5.tar.xz linux-dev-5c7fb56e5e3f7035dd798a8e1adee639f87043e5.zip | |
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 'include/linux/huge_mm.h')
| -rw-r--r-- | include/linux/huge_mm.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 8ca35a131904..d39fa60bd6bf 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -104,7 +104,8 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, #define split_huge_pmd(__vma, __pmd, __address) \ do { \ pmd_t *____pmd = (__pmd); \ - if (pmd_trans_huge(*____pmd)) \ + if (pmd_trans_huge(*____pmd) \ + || pmd_devmap(*____pmd)) \ __split_huge_pmd(__vma, __pmd, __address); \ } while (0) @@ -124,7 +125,7 @@ static inline bool pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, spinlock_t **ptl) { VM_BUG_ON_VMA(!rwsem_is_locked(&vma->vm_mm->mmap_sem), vma); - if (pmd_trans_huge(*pmd)) + if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) return __pmd_trans_huge_lock(pmd, vma, ptl); else return false; |