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Date:   Mon, 7 Mar 2022 09:41:18 +0100
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Subject: Re: [PATCH mmotm v2] mm: delete __ClearPageWaiters()
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To:     Hugh Dickins <hughd@google.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Yu Zhao <yuzhao@google.com>, Yang Shi <shy828301@gmail.com>,
        Michal Hocko <mhocko@suse.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
References: <351df0af-78f2-c20-2a6d-e5f978e5ca1@google.com>
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 <90aafe84-fe7d-c70e-8e15-c222869f30fc@redhat.com>
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 <3eafa969-5b1a-accf-88fe-318784c791a@google.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
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On 04.03.22 22:25, Hugh Dickins wrote:
> The PG_waiters bit is not included in PAGE_FLAGS_CHECK_AT_FREE, and
> vmscan.c's free_unref_page_list() callers rely on that not to generate
> bad_page() alerts.  So __page_cache_release(), put_pages_list() and
> release_pages() (and presumably copy-and-pasted free_zone_device_page())
> are redundant and misleading to make a special point of clearing it (as
> the "__" implies, it could only safely be used on the freeing path).
> 
> Delete __ClearPageWaiters().  Remark on this in one of the "possible"
> comments in folio_wake_bit(), and delete the superfluous comments.
> 
> Signed-off-by: Hugh Dickins <hughd@google.com>
> Tested-by: Yu Zhao <yuzhao@google.com>

Thanks

Reviewed-by: David Hildenbrand <david@redhat.com>


-- 
Thanks,

David / dhildenb