linux-kernel - Re: [PATCH v2 4/5] mm/memory-failure: move hwpoison

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Message-ID: <ZkXbugsIzSWkBk6w@localhost.localdomain>
Date: Thu, 16 May 2024 12:11:06 +0200
From: Oscar Salvador <osalvador@...e.de>
To: Jane Chu <jane.chu@...cle.com>
Cc: linmiaohe@...wei.com, nao.horiguchi@...il.com,
	akpm@...ux-foundation.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/5] mm/memory-failure: move hwpoison_filter() higher
 up

On Fri, May 10, 2024 at 12:26:01AM -0600, Jane Chu wrote:
> Move hwpoison_filter() higher up as there is no need to spend a lot
> cycles only to find out later that the page is supposed to be skipped
> for hwpoison handling.
> 
> Signed-off-by: Jane Chu <jane.chu@...cle.com>
> ---
>  mm/memory-failure.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 62133c10fb51..2fa884d8b5a3 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -2236,6 +2236,13 @@ int memory_failure(unsigned long pfn, int flags)
>  		goto unlock_mutex;
>  	}
>  
> +	if (hwpoison_filter(p)) {
> +		if (flags & MF_COUNT_INCREASED)
> +			put_page(p);
> +		res = -EOPNOTSUPP;
> +		goto unlock_mutex;
> +	}

Now, it is true that doing this might not be optimal for the reasons
explained by Miaohe, but the whole hwpoison_filter() thing is only used
by the hwpoison-inject code AFAICS, which is just for testing purposes,
so I do not think there is any harm in lifting the check.

But no real strong opinion here.


-- 
Oscar Salvador
SUSE Labs