From: Yu Zhao <yuzhao@google.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Nicholas Piggin <npiggin@gmail.com>,
Yang Shi <shy828301@gmail.com>, Michal Hocko <mhocko@suse.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH mmotm] mm: delete __ClearPageWaiters()
Date: Wed, 2 Mar 2022 19:15:02 -0700 [thread overview]
Message-ID: <CAOUHufbJnFNLmS+tKDhsi0jwyXupjNKbs2J_D_1Nqe3UhBOMFA@mail.gmail.com> (raw)
In-Reply-To: <351df0af-78f2-c20-2a6d-e5f978e5ca1@google.com>
On Wed, Mar 2, 2022 at 6:56 PM Hugh Dickins <hughd@google.com> 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())
> 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 wake_up_page_bit(), and delete the superfluous comments.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
> ---
> We've used this since 2018, and I see Yu Zhao posted similar in 2020:
> https://lore.kernel.org/linux-mm/20200818184704.3625199-3-yuzhao@google.com/
> I couldn't join in at that time, but think its reception was over-cautious.
Indeed.
Tested-by: Yu Zhao <yuzhao@google.com>
next prev parent reply other threads:[~2022-03-03 2:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-03 1:56 Hugh Dickins
2022-03-03 2:15 ` Yu Zhao [this message]
2022-03-03 8:54 ` David Hildenbrand
2022-03-03 22:28 ` Hugh Dickins
2022-03-03 22:41 ` Matthew Wilcox
2022-03-04 17:25 ` David Hildenbrand
2022-03-04 21:17 ` Hugh Dickins
2022-03-04 21:25 ` [PATCH mmotm v2] " Hugh Dickins
2022-03-07 8:41 ` David Hildenbrand
2022-03-07 20:17 ` Yang Shi
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