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authorAndi Kleen <ak@linux.intel.com>2010-10-06 19:45:00 (GMT)
committerAndi Kleen <ak@linux.intel.com>2010-10-08 07:32:46 (GMT)
commitaa50d3a7aa8147b9e14dc9d5972a5d2359db4ef8 (patch)
tree68fae5060333dcc24c17e9dd00a87bd760d883e9 /mm/hugetlb.c
parent6f39ce056ab2ab2d29b2fae4aed61ed0b485972f (diff)
Encode huge page size for VM_FAULT_HWPOISON errors
This fixes a problem introduced with the hugetlb hwpoison handling The user space SIGBUS signalling wants to know the size of the hugepage that caused a HWPOISON fault. Unfortunately the architecture page fault handlers do not have easy access to the struct page. Pass the information out in the fault error code instead. I added a separate VM_FAULT_HWPOISON_LARGE bit for this case and encode the hpage index in some free upper bits of the fault code. The small page hwpoison keeps stays with the VM_FAULT_HWPOISON name to minimize changes. Also add code to hugetlb.h to convert that index into a page shift. Will be used in a further patch. Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: fengguang.wu@intel.com Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 67cd032..96991de 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2589,7 +2589,8 @@ retry:
* So we need to block hugepage fault by PG_hwpoison bit check.
*/
if (unlikely(PageHWPoison(page))) {
- ret = VM_FAULT_HWPOISON;
+ ret = VM_FAULT_HWPOISON |
+ VM_FAULT_SET_HINDEX(h - hstates);
goto backout_unlocked;
}
page_dup_rmap(page);
@@ -2656,7 +2657,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
migration_entry_wait(mm, (pmd_t *)ptep, address);
return 0;
} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
- return VM_FAULT_HWPOISON;
+ return VM_FAULT_HWPOISON_LARGE |
+ VM_FAULT_SET_HINDEX(h - hstates);
}
ptep = huge_pte_alloc(mm, address, huge_page_size(h));

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