diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-07-26 15:25:40 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-26 16:19:19 -0700 |
| commit | af9e4d5f2de2eabdc7145e077ba48b2a638465c6 (patch) | |
| tree | 9ac84a9f70046c63d080f99f03bb115745859d9d /mm | |
| parent | d21b9e57c74ce82ac459e2ec8ce667db9b9da8b0 (diff) | |
| download | lwn-af9e4d5f2de2eabdc7145e077ba48b2a638465c6.tar.gz lwn-af9e4d5f2de2eabdc7145e077ba48b2a638465c6.zip | |
thp: handle file COW faults
File COW for THP is handled on pte level: just split the pmd.
It's not clear how benefitial would be allocation of huge pages on COW
faults. And it would require some code to make them work.
I think at some point we can consider teaching khugepaged to collapse
pages in COW mappings, but allocating huge on fault is probably
overkill.
Link: http://lkml.kernel.org/r/1466021202-61880-16-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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c index 10a424eca8a4..8f4254798130 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3446,6 +3446,11 @@ static int wp_huge_pmd(struct fault_env *fe, pmd_t orig_pmd) if (fe->vma->vm_ops->pmd_fault) return fe->vma->vm_ops->pmd_fault(fe->vma, fe->address, fe->pmd, fe->flags); + + /* COW handled on pte level: split pmd */ + VM_BUG_ON_VMA(fe->vma->vm_flags & VM_SHARED, fe->vma); + split_huge_pmd(fe->vma, fe->pmd, fe->address); + return VM_FAULT_FALLBACK; } |