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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>
This commit is contained in:
Song Liu 2018-08-17 15:47:00 -07:00 committed by Linus Torvalds
parent a718e28f53
commit 50f8b92f21
1 changed files with 8 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
mm/khugepaged.c
View File

@ -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;