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| author | Song Liu <songliubraving@fb.com> | 2018-08-18 00:47:00 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-18 01:20:30 +0200 |
| commit | 50f8b92f21d23789bd4ada593e8ddc56cc4f79fe (patch) | |
| tree | ac23602fa31f41df2466e584f6e024364f10f888 /mm/khugepaged.c | |
| parent | mm/fadvise.c: fix signed overflow UBSAN complaint (diff) | |
| download | linux-50f8b92f21d23789bd4ada593e8ddc56cc4f79fe.tar.xz linux-50f8b92f21d23789bd4ada593e8ddc56cc4f79fe.zip | |
mm: thp: pass correct vm_flags to hugepage_vma_check()
khugepaged_enter_vma_merge() passes a stale vma->vm_flags to
hugepage_vma_check(). The argument vm_flags contains the latest value.
Therefore, it is necessary to pass this vm_flags into
hugepage_vma_check().
With this bug, madvise(MADV_HUGEPAGE) for mmap files in shmem fails to
put memory in huge pages. Here is an example of failed madvise():
/* mount /dev/shm with huge=advise:
* mount -o remount,huge=advise /dev/shm */
/* create file /dev/shm/huge */
#define HUGE_FILE "/dev/shm/huge"
fd = open(HUGE_FILE, O_RDONLY);
ptr = mmap(NULL, FILE_SIZE, PROT_READ, MAP_PRIVATE, fd, 0);
ret = madvise(ptr, FILE_SIZE, MADV_HUGEPAGE);
madvise() will return 0, but this memory region is never put in huge
page (check from /proc/meminfo: ShmemHugePages).
Link: http://lkml.kernel.org/r/20180629181752.792831-1-songliubraving@fb.com
Fixes: 02b75dc8160d ("mm: thp: register mm for khugepaged when merging vma for shmem")
Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/khugepaged.c')
| -rw-r--r-- | mm/khugepaged.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 79d55e10bca9..961cbe9062a5 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -397,10 +397,11 @@ static inline int khugepaged_test_exit(struct mm_struct *mm) return atomic_read(&mm->mm_users) == 0; } -static bool hugepage_vma_check(struct vm_area_struct *vma) +static bool hugepage_vma_check(struct vm_area_struct *vma, + unsigned long vm_flags) { - if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || - (vma->vm_flags & VM_NOHUGEPAGE) || + if ((!(vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || + (vm_flags & VM_NOHUGEPAGE) || test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) return false; if (shmem_file(vma->vm_file)) { @@ -413,7 +414,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma) return false; if (is_vma_temporary_stack(vma)) return false; - return !(vma->vm_flags & VM_NO_KHUGEPAGED); + return !(vm_flags & VM_NO_KHUGEPAGED); } int __khugepaged_enter(struct mm_struct *mm) @@ -458,7 +459,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma, * khugepaged does not yet work on non-shmem files or special * mappings. And file-private shmem THP is not supported. */ - if (!hugepage_vma_check(vma)) + if (!hugepage_vma_check(vma, vm_flags)) return 0; hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; @@ -861,7 +862,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, hend = vma->vm_end & HPAGE_PMD_MASK; if (address < hstart || address + HPAGE_PMD_SIZE > hend) return SCAN_ADDRESS_RANGE; - if (!hugepage_vma_check(vma)) + if (!hugepage_vma_check(vma, vma->vm_flags)) return SCAN_VMA_CHECK; return 0; } @@ -1695,7 +1696,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, progress++; break; } - if (!hugepage_vma_check(vma)) { + if (!hugepage_vma_check(vma, vma->vm_flags)) { skip: progress++; continue; |