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Date:   Mon, 21 Feb 2022 13:54:50 +0100
From:   Oscar Salvador <osalvador@suse.de>
To:     Miaohe Lin <linmiaohe@huawei.com>
Cc:     Rik van Riel <riel@surriel.com>, linux-kernel@vger.kernel.org,
        kernel-team@fb.com, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v2] mm: clean up hwpoison page cache page in fault path
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On Wed, Feb 16, 2022 at 10:13:14AM +0800, Miaohe Lin wrote:
> IIUC, this could not happen when soft-offlining a pagecache page. They're either
> invalidated or migrated away and then we set PageHWPoison.
> I think this may happen on a clean pagecache page when it's isolated. So it's !PageLRU.
> And identify_page_state treats it as me_unknown because it's non reserved, slab, swapcache
> and so on ...(see error_states for details). Or am I miss anything?

But the path you are talking about is when we do have a non-recoverable
error, so memory_failure() path.
AFAIU, Rik talks about pages with corrected errors, and that is
soft_offline().

-- 
Oscar Salvador
SUSE Labs