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shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings

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Let's wire up existing madvise() hugepage hints for file mappings.

MADV_HUGEPAGE advise shmem to allocate huge page on page fault in the
VMA.  It only has effect if the filesystem is mounted with huge=advise
or huge=within_size.

MADV_NOHUGEPAGE prevents hugepage from being allocated on page fault in
the VMA.  It doesn't prevent a huge page from being allocated by other
means, i.e.  page fault into different mapping or write(2) into file.

Link: http://lkml.kernel.org/r/1466021202-61880-31-git-send-email-kirill.shutemov@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>
This commit is contained in:
Kirill A. Shutemov
2016-07-26 15:26:21 -07:00
committed by Linus Torvalds
parent 800d8c63b2
commit 657e3038c4
2 changed files with 22 additions and 17 deletions
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19
mm/huge_memory.c
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@@ -1830,7 +1830,7 @@ spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
return NULL;
}
#define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE)
#define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE)
int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
@@ -1846,11 +1846,6 @@ int hugepage_madvise(struct vm_area_struct *vma,
if (mm_has_pgste(vma->vm_mm))
return 0;
#endif
/*
* Be somewhat over-protective like KSM for now!
*/
if (*vm_flags & VM_NO_THP)
return -EINVAL;
*vm_flags &= ~VM_NOHUGEPAGE;
*vm_flags |= VM_HUGEPAGE;
/*
@@ -1858,15 +1853,11 @@ int hugepage_madvise(struct vm_area_struct *vma,
* register it here without waiting a page fault that
* may not happen any time soon.
*/
if (unlikely(khugepaged_enter_vma_merge(vma, *vm_flags)))
if (!(*vm_flags & VM_NO_KHUGEPAGED) &&
khugepaged_enter_vma_merge(vma, *vm_flags))
return -ENOMEM;
break;
case MADV_NOHUGEPAGE:
/*
* Be somewhat over-protective like KSM for now!
*/
if (*vm_flags & VM_NO_THP)
return -EINVAL;
*vm_flags &= ~VM_HUGEPAGE;
*vm_flags |= VM_NOHUGEPAGE;
/*
@@ -1974,7 +1965,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma,
* page fault if needed.
*/
return 0;
if (vma->vm_ops || (vm_flags & VM_NO_THP))
if (vma->vm_ops || (vm_flags & VM_NO_KHUGEPAGED))
/* khugepaged not yet working on file or special mappings */
return 0;
hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
@@ -2366,7 +2357,7 @@ 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_THP);
return !(vma->vm_flags & VM_NO_KHUGEPAGED);
}
/*