Re: [PATCH] mm: remove PageWriteback

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Sat, Sep 05, 2026 at 03:08:30PM -0400, Tal Zussman wrote:
> The last caller of PageWriteback() was removed in commit f75987e543c2
> ("libceph: remove pinning assertion in ceph_msg_data_iter_next()").
> This flag is now only used on folios, so we can remove all the page
> accessors. folio_test_clear_writeback() is not used, so don't add
> FOLIO_TEST_CLEAR_FLAG() for it.
>
> Signed-off-by: Tal Zussman <tz2294@columbia.edu>

Nice! LGTM so:

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

> ---
>  include/linux/page-flags.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 3dc79c0c5adf..86dd0470da11 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -588,8 +588,8 @@ FOLIO_FLAG(owner_2, FOLIO_HEAD_PAGE)
>   * Only test-and-set exist for PG_writeback.  The unconditional operators are
>   * risky: they bypass page accounting.
>   */
> -TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
> -	TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
> +FOLIO_TEST_FLAG(writeback, FOLIO_HEAD_PAGE)
> +	FOLIO_TEST_SET_FLAG(writeback, FOLIO_HEAD_PAGE)
>  FOLIO_FLAG(mappedtodisk, FOLIO_HEAD_PAGE)
>
>  /* PG_readahead is only used for reads; PG_reclaim is only for writes */
>
> ---
> base-commit: b733fe31e781ed45c56d2ec561dbb61a903693c8
> change-id: 20260904-remove-pagewriteback-69d2aa5b3ee9
>
> Best regards,
> --
> Tal Zussman <tz2294@columbia.edu>
>

--
Cheers, Lorenzo