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Date:   Thu, 3 Mar 2022 22:41:38 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Hugh Dickins <hughd@google.com>
Cc:     David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.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
Subject: Re: [PATCH mmotm] mm: delete __ClearPageWaiters()
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On Thu, Mar 03, 2022 at 02:28:46PM -0800, Hugh Dickins wrote:
> On Thu, 3 Mar 2022, David Hildenbrand wrote:
> > On 03.03.22 02:56, 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() and release_pages() (and
> > > the presumably copy-and-pasted put_zone_device_private_or_public_page())
> 
> Hah, I'm showing my age there, or the patch's age: it's been rebranded
> frequently since then, with linux-next calling it free_zone_device_page(),
> as you kindly point out.  How long before it's free_zone_device_folio()?

Probably not a serious question, but within the next year, I expect.
I have a prototype patch to do the entire page freeing path, but it
wasn't a priority for this merge window.