Re: [PATCH v2 2/4] mm/hwpoison: fix miss catch transparent huge page

[Wanpeng Li <liwanp@linux.vnet.ibm.com>]

On Tue, Sep 03, 2013 at 04:04:25AM -0400, Chen Gong wrote:
>On Tue, Sep 03, 2013 at 12:18:58PM +0800, Wanpeng Li wrote:
>> Date: Tue, 3 Sep 2013 12:18:58 +0800
>> From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>> To: Chen Gong <gong.chen@linux.intel.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>, Andi Kleen
>>  <andi@firstfloor.org>, Fengguang Wu <fengguang.wu@intel.com>, Naoya
>>  Horiguchi <n-horiguchi@ah.jp.nec.com>, Tony Luck <tony.luck@intel.com>,
>>  linux-mm@kvack.org, linux-kernel@vger.kernel.org
>> Subject: Re: [PATCH v2 2/4] mm/hwpoison: fix miss catch transparent huge
>>  page
>> User-Agent: Mutt/1.5.21 (2010-09-15)
>> 
>> On Mon, Sep 02, 2013 at 11:15:19PM -0400, Chen Gong wrote:
>> >On Tue, Sep 03, 2013 at 07:36:44AM +0800, Wanpeng Li wrote:
>> >> Date: Tue,  3 Sep 2013 07:36:44 +0800
>> >> From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>> >> To: Andrew Morton <akpm@linux-foundation.org>
>> >> Cc: Andi Kleen <andi@firstfloor.org>, Fengguang Wu
>> >>  <fengguang.wu@intel.com>, Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
>> >>  Tony Luck <tony.luck@intel.com>, gong.chen@linux.intel.com,
>> >>  linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wanpeng Li
>> >>  <liwanp@linux.vnet.ibm.com>
>> >> Subject: [PATCH v2 2/4] mm/hwpoison: fix miss catch transparent huge page 
>> >> X-Mailer: git-send-email 1.7.5.4
>> >> 
>> >> Changelog:
>> >>  *v1 -> v2: reverse PageTransHuge(page) && !PageHuge(page) check 
>> >> 
>> >> 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@linux.vnet.ibm.com>
>> >> ---
>> >>  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 (!PageHuge(page) && PageTransHuge(page)) {
>> >>  		pr_info("MCE: Memory failure is now running on %#lx\n", pfn);
>> >>  			return 0;
>> >>  	}
>> >
>> >Not sure which git tree should be used to apply this patch series? I assume
>> >this patch series follows this link: https://lkml.org/lkml/2013/8/26/76.
>> >
>> 
>> mmotm tree or linux-next. ;-)
>> 
>> >In unpoison_memory we already have
>> >        if (PageHuge(page)) {
>> >                ...
>> >                return 0;
>> >        }
>> >so it looks like this patch is redundant.
>> 
>> - Do you aware there is condition before go to this check?
>> - Do you also analysis why the check can't catch the hugetlbfs page
>>   through the dump information?
>> 
>
>Looks like we use different trees. After checking your working tree,
>your patch is right. So just ignore my words above. FWIW, please be

Thanks. 

>polite and give a positive response.
>

It's my fault, sorry for that. 

Regards,
Wanpeng Li 

>> Regards,
>> Wanpeng Li 
>> 
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