[PATCH][mm:] adjust the logic of checking THP

From: Guanjun He
Date: Tue Nov 01 2011 - 07:42:38 EST



Signed-off-by: Guanjun He <heguanbo@xxxxxxxxx>
---
mm/memory.c | 32 ++++++++++++++++++--------------
1 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index a56e3ba..d6dd6b3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3465,20 +3465,24 @@ int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
pmd = pmd_alloc(mm, pud, address);
if (!pmd)
return VM_FAULT_OOM;
- if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
- if (!vma->vm_ops)
- return do_huge_pmd_anonymous_page(mm, vma, address,
- pmd, flags);
- } else {
- pmd_t orig_pmd = *pmd;
- barrier();
- if (pmd_trans_huge(orig_pmd)) {
- if (flags & FAULT_FLAG_WRITE &&
- !pmd_write(orig_pmd) &&
- !pmd_trans_splitting(orig_pmd))
- return do_huge_pmd_wp_page(mm, vma, address,
- pmd, orig_pmd);
- return 0;
+ if (transparent_hugepage_enabled(vma)) {
+ if(pmd_none(*pmd)){
+ if (!vma->vm_ops)
+ return do_huge_pmd_anonymous_page(mm, vma, address,
+ pmd, flags);
+ }
+ else
+ {
+ pmd_t orig_pmd = *pmd;
+ barrier();
+ if (pmd_trans_huge(orig_pmd)) {
+ if (flags & FAULT_FLAG_WRITE &&
+ !pmd_write(orig_pmd) &&
+ !pmd_trans_splitting(orig_pmd))
+ return do_huge_pmd_wp_page(mm, vma, address,
+ pmd, orig_pmd);
+ return 0;
+ }
}
}

--
1.7.7

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