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From: Yun Levi <ppbuk5246@gmail.com>
Date: Mon, 26 Feb 2024 19:44:44 +0000
Message-ID: <CAM7-yPS-=NCceH6O7C0b_NvE69Aq9zpMruy+0jnB34HsNo8ZFg@mail.gmail.com>
Subject: Re: [PATCH] kswapd: Replace try_to_freeze to kthread_freezable_should_stop.
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
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Gentle ping.

On Fri, Jan 26, 2024 at 3:26=E2=80=AFPM Levi Yun <ppbuk5246@gmail.com> wrot=
e:
>
> Instead of using try_to_freeze, use kthread_freezable_should_stop in
> kswapd.
> By this, we can avoid unnecessary freezing when kswapd should stop.
>
> Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
> ---
>  mm/vmscan.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 4f9c854ce6cc..1f139830b26f 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -6796,6 +6796,7 @@ static int balance_pgdat(pg_data_t *pgdat, int orde=
r, int highest_zoneidx)
>                 bool raise_priority =3D true;
>                 bool balanced;
>                 bool ret;
> +               bool was_frozen;
>
>                 sc.reclaim_idx =3D highest_zoneidx;
>
> @@ -6894,9 +6895,9 @@ static int balance_pgdat(pg_data_t *pgdat, int orde=
r, int highest_zoneidx)
>
>                 /* Check if kswapd should be suspending */
>                 __fs_reclaim_release(_THIS_IP_);
> -               ret =3D try_to_freeze();
> +               ret =3D kthread_freezable_should_stop(&was_frozen);
>                 __fs_reclaim_acquire(_THIS_IP_);
> -               if (ret || kthread_should_stop())
> +               if (was_frozen || ret)
>                         break;
>
>                 /*
> @@ -7102,7 +7103,7 @@ static int kswapd(void *p)
>         WRITE_ONCE(pgdat->kswapd_highest_zoneidx, MAX_NR_ZONES);
>         atomic_set(&pgdat->nr_writeback_throttled, 0);
>         for ( ; ; ) {
> -               bool ret;
> +               bool was_frozen;
>
>                 alloc_order =3D reclaim_order =3D READ_ONCE(pgdat->kswapd=
_order);
>                 highest_zoneidx =3D kswapd_highest_zoneidx(pgdat,
> @@ -7119,15 +7120,14 @@ static int kswapd(void *p)
>                 WRITE_ONCE(pgdat->kswapd_order, 0);
>                 WRITE_ONCE(pgdat->kswapd_highest_zoneidx, MAX_NR_ZONES);
>
> -               ret =3D try_to_freeze();
> -               if (kthread_should_stop())
> +               if (kthread_freezable_should_stop(&was_frozen))
>                         break;
>
>                 /*
>                  * We can speed up thawing tasks if we don't call balance=
_pgdat
>                  * after returning from the refrigerator
>                  */
> -               if (ret)
> +               if (was_frozen)
>                         continue;
>
>                 /*
> --
> 2.39.2