Re: [PATCH v4 18/48] rcu: dynamically allocate the rcu-lazy shrinker

Joel Fernandes
2023-08-07T14:16:18Z

On Mon, Aug 7, 2023 at 7:36 AM Qi Zheng <zhengqi.arch@bytedance.com> wrote:
>
> Use new APIs to dynamically allocate the rcu-lazy shrinker.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>

For RCU:
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>

thanks,

- Joel

> ---
> kernel/rcu/tree_nocb.h | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
> index 5598212d1f27..e1c59c33738a 100644
> --- a/kernel/rcu/tree_nocb.h
> +++ b/kernel/rcu/tree_nocb.h
> @@ -1396,13 +1396,6 @@ lazy_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
>
> return count ? count : SHRINK_STOP;
> }
> -
> -static struct shrinker lazy_rcu_shrinker = {
> - .count_objects = lazy_rcu_shrink_count,
> - .scan_objects = lazy_rcu_shrink_scan,
> - .batch = 0,
> - .seeks = DEFAULT_SEEKS,
> -};
> #endif // #ifdef CONFIG_RCU_LAZY
>
> void __init rcu_init_nohz(void)
> @@ -1410,6 +1403,7 @@ void __init rcu_init_nohz(void)
> int cpu;
> struct rcu_data *rdp;
> const struct cpumask *cpumask = NULL;
> + struct shrinker * __maybe_unused lazy_rcu_shrinker;
>
> #if defined(CONFIG_NO_HZ_FULL)
> if (tick_nohz_full_running && !cpumask_empty(tick_nohz_full_mask))
> @@ -1436,8 +1430,16 @@ void __init rcu_init_nohz(void)
> return;
>
> #ifdef CONFIG_RCU_LAZY
> - if (register_shrinker(&lazy_rcu_shrinker, "rcu-lazy"))
> - pr_err("Failed to register lazy_rcu shrinker!\n");
> + lazy_rcu_shrinker = shrinker_alloc(0, "rcu-lazy");
> + if (!lazy_rcu_shrinker) {
> + pr_err("Failed to allocate lazy_rcu shrinker!\n");
> + } else {
> + lazy_rcu_shrinker->count_objects = lazy_rcu_shrink_count;
> + lazy_rcu_shrinker->scan_objects = lazy_rcu_shrink_scan;
> + lazy_rcu_shrinker->seeks = DEFAULT_SEEKS;
> +
> + shrinker_register(lazy_rcu_shrinker);
> + }
> #endif // #ifdef CONFIG_RCU_LAZY
>
> if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
> --
> 2.30.2
>