mm, hwpoison: remove obsolete comment

[PATCH v1] mm, hwpoison: remove obsolete comment

Posted by Naoya Horiguchi 4 years, 5 months ago

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);
-- 
2.25.1

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

Posted by Miaohe Lin 4 years, 5 months ago

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>

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

Posted by Anshuman Khandual 4 years, 5 months ago


On 1/25/22 8:26 AM, 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);
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

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

Posted by Oscar Salvador 4 years, 5 months ago

On 2022-01-25 03:56, 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>

Reviewed-by: Oscar Salvador <osalvador@suse.de>


-- 
Oscar Salvador
SUSE Labs

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

Posted by Yang Shi 4 years, 5 months ago

On Mon, Jan 24, 2022 at 6:56 PM Naoya Horiguchi
<naoya.horiguchi@linux.dev> 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>

Reviewed-by: Yang Shi <shy828301@gmail.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);
> --
> 2.25.1
>
>