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From: David Hildenbrand <david@redhat.com>
To: Wei Yang <richardw.yang@linux.intel.com>,
	n-horiguchi@ah.jp.nec.com, akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm/memory-failure.c: PageHuge is handled at the beginning of memory_failure
Date: Tue, 19 Nov 2019 13:23:54 +0100
Message-ID: <1e61c115-5787-9ef4-a449-2e490c53fca7@redhat.com> (raw)
In-Reply-To: <20191118082003.26240-1-richardw.yang@linux.intel.com>

On 18.11.19 09:20, Wei Yang wrote:
> PageHuge is handled by memory_failure_hugetlb(), so this case could be
> removed.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> ---
>   mm/memory-failure.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 3151c87dff73..392ac277b17d 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1359,10 +1359,7 @@ int memory_failure(unsigned long pfn, int flags)
>   	 * page_remove_rmap() in try_to_unmap_one(). So to determine page status
>   	 * correctly, we save a copy of the page flags at this time.
>   	 */
> -	if (PageHuge(p))
> -		page_flags = hpage->flags;
> -	else
> -		page_flags = p->flags;
> +	page_flags = p->flags;
>   
>   	/*
>   	 * unpoison always clear PG_hwpoison inside page lock
> 

I somewhat miss a proper explanation why this is safe to do. We access 
page flags here, so why is it safe to refer to the ones of the sub-page?

-- 

Thanks,

David / dhildenb



  parent reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-18  8:20 Wei Yang
2019-11-18  8:20 ` [PATCH 2/2] mm/memory-failure.c: not necessary to recalculate hpage Wei Yang
2019-11-20 15:07   ` David Hildenbrand
2019-11-21  1:05     ` Wei Yang
2019-12-02 22:28     ` Wei Yang
2019-12-05 15:06       ` David Hildenbrand
2019-12-06  1:48         ` Wei Yang
2020-01-08 12:20           ` David Hildenbrand
2020-01-09  1:58             ` Wei Yang
2019-11-19 12:23 ` David Hildenbrand [this message]
2019-11-20  0:46   ` [PATCH 1/2] mm/memory-failure.c: PageHuge is handled at the beginning of memory_failure Wei Yang
2019-11-20 15:04     ` David Hildenbrand
2019-11-21  1:07       ` Wei Yang

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