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From: Matthew Wilcox <willy@infradead.org>
To: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	akpm@linux-foundation.org, linmiaohe@huawei.com,
	naoya.horiguchi@nec.com
Subject: Re: [PATCH mm-unstable 8/8] mm/memory-failure: convert unpoison_memory() to folios
Date: Sat, 15 Jul 2023 05:07:03 +0100	[thread overview]
Message-ID: <ZLIbZygG7LqSI9xe@casper.infradead.org> (raw)
In-Reply-To: <20230112204608.80136-9-sidhartha.kumar@oracle.com>

On Thu, Jan 12, 2023 at 02:46:08PM -0600, Sidhartha Kumar wrote:
> @@ -2348,7 +2347,6 @@ int unpoison_memory(unsigned long pfn)
>  		return -ENXIO;
>  
>  	p = pfn_to_page(pfn);
> -	page = compound_head(p);
>  	folio = page_folio(p);
>  
>  	mutex_lock(&mf_mutex);
> @@ -2360,31 +2358,31 @@ int unpoison_memory(unsigned long pfn)
>  		goto unlock_mutex;
>  	}
>  
> -	if (!PageHWPoison(p)) {
> +	if (!folio_test_hwpoison(folio)) {

This is wrong.  You need to test the individual page for PageHWPoison()
instead of testing the folio.  I understand that this will work for
hugetlbfs pages, but for THP, it's the individual pages that get poisoned,
and folio_test_hwpoison() on a THP actually only tests the head page.

Ideas for preventing this mistake in the future gratefully received.


  reply	other threads:[~2023-07-15  4:07 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-12 20:46 [PATCH mm-unstable 0/8] convert hugepage memory failure functions " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 1/8] mm/memory-failure: convert __get_huge_page_for_hwpoison() " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 2/8] mm/memory-failure: convert try_memory_failure_hugetlb() " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 3/8] mm/memory-failure: convert hugetlb_clear_page_hwpoison " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 4/8] mm/memory-failure: convert free_raw_hwp_pages() " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 5/8] mm/memory-failure: convert raw_hwp_list_head() " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 6/8] mm/memory-failure: convert __free_raw_hwp_pages() " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 7/8] mm/memory-failure: convert hugetlb_set_page_hwpoison() " Sidhartha Kumar
2023-01-12 20:46 ` [PATCH mm-unstable 8/8] mm/memory-failure: convert unpoison_memory() " Sidhartha Kumar
2023-07-15  4:07   ` Matthew Wilcox [this message]
2023-01-13  7:03 ` [PATCH mm-unstable 0/8] convert hugepage memory failure functions " HORIGUCHI NAOYA(堀口 直也)
2023-01-13 16:06   ` Sidhartha Kumar

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