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

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Date:	Mon, 2 Sep 2013 23:15:19 -0400
From:	Chen Gong <gong.chen@...ux.intel.com>
To:	Wanpeng Li <liwanp@...ux.vnet.ibm.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Andi Kleen <andi@...stfloor.org>,
	Fengguang Wu <fengguang.wu@...el.com>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Tony Luck <tony.luck@...el.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] mm/hwpoison: fix miss catch transparent huge page

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@...ux.vnet.ibm.com>
> To: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Andi Kleen <andi@...stfloor.org>, Fengguang Wu
>  <fengguang.wu@...el.com>, Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
>  Tony Luck <tony.luck@...el.com>, gong.chen@...ux.intel.com,
>  linux-mm@...ck.org, linux-kernel@...r.kernel.org, Wanpeng Li
>  <liwanp@...ux.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@...ux.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.

In unpoison_memory we already have
        if (PageHuge(page)) {
                ...
                return 0;
        }
so it looks like this patch is redundant.

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