Hi Naoya,
On Mon, Sep 02, 2013 at 02:34:20PM -0400, Naoya Horiguchi wrote:
>On Mon, Sep 02, 2013 at 08:33:42PM +0800, Wanpeng Li wrote:
>> PageTransHuge() can't guarantee the page is transparent huge page since it
>> return true for both transparent huge and hugetlbfs pages. This patch fix
>> it by check the page is also !hugetlbfs page.
>>
>> Before patch:
>>
>> [ 121.571128] Injecting memory failure at pfn 23a200
>> [ 121.571141] MCE 0x23a200: huge page recovery: Delayed
>> [ 140.355100] MCE: Memory failure is now running on 0x23a200
>>
>> After patch:
>>
>> [ 94.290793] Injecting memory failure at pfn 23a000
>> [ 94.290800] MCE 0x23a000: huge page recovery: Delayed
>> [ 105.722303] MCE: Software-unpoisoned page 0x23a000
>>
>> Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
>
>PageTransHuge doesn't care about hugetlbfs at all, assuming that it
>shouldn't be called hugetlbfs context as commented.
>
> /*
> * PageHuge() only returns true for hugetlbfs pages, but not for
> * normal or transparent huge pages.
> *
> * PageTransHuge() returns true for both transparent huge and
> * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
> * called only in the core VM paths where hugetlbfs pages can't exist.
> */
> static inline int PageTransHuge(struct page *page)
>
>I think it's for the ultra optimization of thp, so we can't change that.
>So we need to follow the pattern whenever possible.
>
> if (PageHuge) {
> hugetlb specific code
> } else if (PageTransHuge) {
> thp specific code
> }
> normal page code / common code
>
>> ---
>> mm/memory-failure.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index e28ee77..b114570 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -1349,7 +1349,7 @@ int unpoison_memory(unsigned long pfn)
>> * worked by memory_failure() and the page lock is not held yet.
>> * In such case, we yield to memory_failure() and make unpoison fail.
>> */
>> - if (PageTransHuge(page)) {
>> + if (PageTransHuge(page) && !PageHuge(page)) {
>> pr_info("MCE: Memory failure is now running on %#lx\n", pfn);
>> return 0;
>> }
>
>I think that we can effectively follow the above pattern by reversing
>these two checks.
Ok, I will do it this way.
Btw, thanks for your review the patchset. ;-)
Regards,
Wanpeng Li
>
>Thanks,
>Naoya Horiguchi
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