Commit 50f8b92f authored by Song Liu's avatar Song Liu Committed by Linus Torvalds

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: default avatarSong Liu <songliubraving@fb.com>
Reviewed-by: default avatarRik van Riel <riel@surriel.com>
Reviewed-by: default avatarYang 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a718e28f
...@@ -397,10 +397,11 @@ static inline int khugepaged_test_exit(struct mm_struct *mm) ...@@ -397,10 +397,11 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
return atomic_read(&mm->mm_users) == 0; 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()) || if ((!(vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
(vma->vm_flags & VM_NOHUGEPAGE) || (vm_flags & VM_NOHUGEPAGE) ||
test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
return false; return false;
if (shmem_file(vma->vm_file)) { if (shmem_file(vma->vm_file)) {
...@@ -413,7 +414,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma) ...@@ -413,7 +414,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
return false; return false;
if (is_vma_temporary_stack(vma)) if (is_vma_temporary_stack(vma))
return false; return false;
return !(vma->vm_flags & VM_NO_KHUGEPAGED); return !(vm_flags & VM_NO_KHUGEPAGED);
} }
int __khugepaged_enter(struct mm_struct *mm) int __khugepaged_enter(struct mm_struct *mm)
...@@ -458,7 +459,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma, ...@@ -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 * khugepaged does not yet work on non-shmem files or special
* mappings. And file-private shmem THP is not supported. * mappings. And file-private shmem THP is not supported.
*/ */
if (!hugepage_vma_check(vma)) if (!hugepage_vma_check(vma, vm_flags))
return 0; return 0;
hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; 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, ...@@ -861,7 +862,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
hend = vma->vm_end & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK;
if (address < hstart || address + HPAGE_PMD_SIZE > hend) if (address < hstart || address + HPAGE_PMD_SIZE > hend)
return SCAN_ADDRESS_RANGE; return SCAN_ADDRESS_RANGE;
if (!hugepage_vma_check(vma)) if (!hugepage_vma_check(vma, vma->vm_flags))
return SCAN_VMA_CHECK; return SCAN_VMA_CHECK;
return 0; return 0;
} }
...@@ -1695,7 +1696,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, ...@@ -1695,7 +1696,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
progress++; progress++;
break; break;
} }
if (!hugepage_vma_check(vma)) { if (!hugepage_vma_check(vma, vma->vm_flags)) {
skip: skip:
progress++; progress++;
continue; continue;
......
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