On Wed, Mar 2, 2022 at 6:56 PM Hugh Dickins <hughd@xxxxxxxxxx> 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@xxxxxxxxxx> > --- > 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@xxxxxxxxxx/ > I couldn't join in at that time, but think its reception was over-cautious. Indeed. Tested-by: Yu Zhao <yuzhao@xxxxxxxxxx>
