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Song Liu authored
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>
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