linux-kernel - Re: [PATCH v2] mm/memory-failure: Fix redundant updates for already poisoned pages

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Message-ID: <2d5498a6-e07c-4a4f-8ab5-2a007c08bd70@oracle.com>
Date: Thu, 28 Aug 2025 15:53:01 -0700
From: jane.chu@...cle.com
To: Kyle Meyer <kyle.meyer@....com>, akpm@...ux-foundation.org,
        linmiaohe@...wei.com, jiaqiyan@...gle.com
Cc: bp@...en8.de, david@...hat.com, Liam.Howlett@...cle.com,
        linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, lorenzo.stoakes@...cle.com, mhocko@...e.com,
        nao.horiguchi@...il.com, osalvador@...e.de, rppt@...nel.org,
        russ.anderson@....com, surenb@...gle.com, tony.luck@...el.com,
        vbabka@...e.cz
Subject: Re: [PATCH v2] mm/memory-failure: Fix redundant updates for already
 poisoned pages



On 8/28/2025 11:38 AM, Kyle Meyer wrote:
> Duplicate memory errors can be reported by multiple sources.
> 
> Passing an already poisoned page to action_result() causes issues:
> 
> * The amount of hardware corrupted memory is incorrectly updated.
> * Per NUMA node MF stats are incorrectly updated.
> * Redundant "already poisoned" messages are printed.
> 
> Avoid those issues by:
> 
> * Skipping hardware corrupted memory updates for already poisoned pages.
> * Skipping per NUMA node MF stats updates for already poisoned pages.
> * Dropping redundant "already poisoned" messages.
> 
> Make MF_MSG_ALREADY_POISONED consistent with other action_page_types and
> make calls to action_result() consistent for already poisoned
> normal pages and huge pages.
> 
> Fixes: b8b9488d50b7 ("mm/memory-failure: improve memory failure action_result messages")
> Signed-off-by: Kyle Meyer <kyle.meyer@....com>
> ---
> 
> v1 -> v2:
>   * Continue passing poisoned pages to action_result() with MF_FAILED but don't
> update anything.
>   * https://lore.kernel.org/all/20250821164445.14467-1-kyle.meyer@hpe.com
> 
> ---
>   mm/memory-failure.c | 13 ++++++-------
>   1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index fc30ca4804bf..10b3c281c2ae 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -956,7 +956,7 @@ static const char * const action_page_types[] = {
>   	[MF_MSG_BUDDY]			= "free buddy page",
>   	[MF_MSG_DAX]			= "dax page",
>   	[MF_MSG_UNSPLIT_THP]		= "unsplit thp",
> -	[MF_MSG_ALREADY_POISONED]	= "already poisoned",
> +	[MF_MSG_ALREADY_POISONED]	= "already poisoned page",
>   	[MF_MSG_UNKNOWN]		= "unknown page",
>   };
>   
> @@ -1349,9 +1349,10 @@ static int action_result(unsigned long pfn, enum mf_action_page_type type,
>   {
>   	trace_memory_failure_event(pfn, type, result);
>   
> -	num_poisoned_pages_inc(pfn);
> -
> -	update_per_node_mf_stats(pfn, result);
> +	if (type != MF_MSG_ALREADY_POISONED) {
> +		num_poisoned_pages_inc(pfn);
> +		update_per_node_mf_stats(pfn, result);
> +	}
>   
>   	pr_err("%#lx: recovery action for %s: %s\n",
>   		pfn, action_page_types[type], action_name[result]);
> @@ -2094,12 +2095,11 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb
>   		*hugetlb = 0;
>   		return 0;
>   	} else if (res == -EHWPOISON) {
> -		pr_err("%#lx: already hardware poisoned\n", pfn);
>   		if (flags & MF_ACTION_REQUIRED) {
>   			folio = page_folio(p);
>   			res = kill_accessing_process(current, folio_pfn(folio), flags);
> -			action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);
>   		}
> +		action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);
>   		return res;
>   	} else if (res == -EBUSY) {
>   		if (!(flags & MF_NO_RETRY)) {
> @@ -2285,7 +2285,6 @@ int memory_failure(unsigned long pfn, int flags)
>   		goto unlock_mutex;
>   
>   	if (TestSetPageHWPoison(p)) {
> -		pr_err("%#lx: already hardware poisoned\n", pfn);
>   		res = -EHWPOISON;
>   		if (flags & MF_ACTION_REQUIRED)
>   			res = kill_accessing_process(current, pfn, flags);

Looks good, thanks!

Reviewed-by: Jane Chu <jane.chu@...cle.com>

-jane