| Message ID | 1457737157-38573-11-git-send-email-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/mm/memory.c b/mm/memory.c index f7a73b6cabac..c0a2510b9e15 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3366,6 +3366,11 @@ 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; }
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. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- mm/memory.c | 5 +++++ 1 file changed, 5 insertions(+)