Re: [PATCH v4 19/48] rcu: dynamically allocate the rcu-kfree shrinker

[Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>]

On Mon, Aug 7, 2023 at 7:17 AM Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> wrote:
>
> Use new APIs to dynamically allocate the rcu-kfree shrinker.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>

For RCU:
Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>

thanks,

- Joel


> ---
>  kernel/rcu/tree.c | 22 +++++++++++++---------
>  1 file changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index 7c79480bfaa0..3b20fc46c514 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -3449,13 +3449,6 @@ kfree_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
>         return freed == 0 ? SHRINK_STOP : freed;
>  }
>
> -static struct shrinker kfree_rcu_shrinker = {
> -       .count_objects = kfree_rcu_shrink_count,
> -       .scan_objects = kfree_rcu_shrink_scan,
> -       .batch = 0,
> -       .seeks = DEFAULT_SEEKS,
> -};
> -
>  void __init kfree_rcu_scheduler_running(void)
>  {
>         int cpu;
> @@ -4931,6 +4924,7 @@ static void __init kfree_rcu_batch_init(void)
>  {
>         int cpu;
>         int i, j;
> +       struct shrinker *kfree_rcu_shrinker;
>
>         /* Clamp it to [0:100] seconds interval. */
>         if (rcu_delay_page_cache_fill_msec < 0 ||
> @@ -4962,8 +4956,18 @@ static void __init kfree_rcu_batch_init(void)
>                 INIT_DELAYED_WORK(&krcp->page_cache_work, fill_page_cache_func);
>                 krcp->initialized = true;
>         }
> -       if (register_shrinker(&kfree_rcu_shrinker, "rcu-kfree"))
> -               pr_err("Failed to register kfree_rcu() shrinker!\n");
> +
> +       kfree_rcu_shrinker = shrinker_alloc(0, "rcu-kfree");
> +       if (!kfree_rcu_shrinker) {
> +               pr_err("Failed to allocate kfree_rcu() shrinker!\n");
> +               return;
> +       }
> +
> +       kfree_rcu_shrinker->count_objects = kfree_rcu_shrink_count;
> +       kfree_rcu_shrinker->scan_objects = kfree_rcu_shrink_scan;
> +       kfree_rcu_shrinker->seeks = DEFAULT_SEEKS;
> +
> +       shrinker_register(kfree_rcu_shrinker);
>  }
>
>  void __init rcu_init(void)
> --
> 2.30.2
>