Re: [PATCH v1] mm, hwpoison: remove obsolete comment

From: Miaohe Lin <linmiaohe@huawei.com>
To: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Tony Luck <tony.luck@intel.com>,
	Naoya Horiguchi <naoya.horiguchi@nec.com>,
	<linux-kernel@vger.kernel.org>, Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH v1] mm, hwpoison: remove obsolete comment
Date: Tue, 25 Jan 2022 11:08:27 +0800	[thread overview]
Message-ID: <4ee2ff7b-4aaf-437d-6827-ebf95bcf6db5@huawei.com> (raw)
In-Reply-To: <20220125025601.3054511-1-naoya.horiguchi@linux.dev>

Hi:
On 2022/1/25 10:56, Naoya Horiguchi wrote:
> From: Naoya Horiguchi <naoya.horiguchi@nec.com>
> 
> With the introduction of mf_mutex, most of memory error handling
> process is mutually exclusive, so the in-line comment about
> subtlety about double-checking PageHWPoison is no more correct.
> So remove it.
> 
> Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
> ---
>  mm/memory-failure.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 4c9bd1d37301..a6a1e02759e7 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -2146,12 +2146,6 @@ static int __soft_offline_page(struct page *page)
>  		.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
>  	};
>  
> -	/*
> -	 * Check PageHWPoison again inside page lock because PageHWPoison
> -	 * is set by memory_failure() outside page lock. Note that
> -	 * memory_failure() also double-checks PageHWPoison inside page lock,
> -	 * so there's no race between soft_offline_page() and memory_failure().
> -	 */
>  	lock_page(page);
>  	if (!PageHuge(page))
>  		wait_on_page_writeback(page);
> 

Looks good to me. Thanks for the patch.

Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>