2023-01-30 07:12:51

by Zqiang

Subject: [PATCH] rcu: Register rcu-lazy shrinker only CONFIG_RCU_LAZY is enabled

The rcu-lazy shrinker is registered without CONFIG_RCU_LAZY enabled
is meaningless, this commit therefore make rcu-lazy shrinker is
registered only when CONFIG_RCU_LAZY is enabled.

Signed-off-by: Zqiang <[email protected]>
---
kernel/rcu/tree_nocb.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index 9e1c8caec5ce..28c1c092817b 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -1312,6 +1312,7 @@ int rcu_nocb_cpu_offload(int cpu)
}
EXPORT_SYMBOL_GPL(rcu_nocb_cpu_offload);

+#ifdef CONFIG_RCU_LAZY
static unsigned long
lazy_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
{
@@ -1360,6 +1361,7 @@ static struct shrinker lazy_rcu_shrinker = {
.batch = 0,
.seeks = DEFAULT_SEEKS,
};
+#endif

void __init rcu_init_nohz(void)
{
@@ -1391,8 +1393,10 @@ void __init rcu_init_nohz(void)
if (!rcu_state.nocb_is_setup)
return;

+#ifdef CONFIG_RCU_LAZY
if (register_shrinker(&lazy_rcu_shrinker, "rcu-lazy"))
pr_err("Failed to register lazy_rcu shrinker!\n");
+#endif

if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n");
--
2.25.1

2023-01-30 15:01:00

by Joel Fernandes

Subject: Re: [PATCH] rcu: Register rcu-lazy shrinker only CONFIG_RCU_LAZY is enabled

On Mon, Jan 30, 2023 at 2:12 AM Zqiang <[email protected]> wrote:
>
> The rcu-lazy shrinker is registered without CONFIG_RCU_LAZY enabled
> is meaningless, this commit therefore make rcu-lazy shrinker is
> registered only when CONFIG_RCU_LAZY is enabled.
>
> Signed-off-by: Zqiang <[email protected]>

Reviewed-by: Joel Fernandes (Google) <[email protected]>

Thanks.

> ---
> kernel/rcu/tree_nocb.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
> index 9e1c8caec5ce..28c1c092817b 100644
> --- a/kernel/rcu/tree_nocb.h
> +++ b/kernel/rcu/tree_nocb.h
> @@ -1312,6 +1312,7 @@ int rcu_nocb_cpu_offload(int cpu)
> }
> EXPORT_SYMBOL_GPL(rcu_nocb_cpu_offload);
>
> +#ifdef CONFIG_RCU_LAZY
> static unsigned long
> lazy_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
> {
> @@ -1360,6 +1361,7 @@ static struct shrinker lazy_rcu_shrinker = {
> .batch = 0,
> .seeks = DEFAULT_SEEKS,
> };
> +#endif
>
> void __init rcu_init_nohz(void)
> {
> @@ -1391,8 +1393,10 @@ void __init rcu_init_nohz(void)
> if (!rcu_state.nocb_is_setup)
> return;
>
> +#ifdef CONFIG_RCU_LAZY
> if (register_shrinker(&lazy_rcu_shrinker, "rcu-lazy"))
> pr_err("Failed to register lazy_rcu shrinker!\n");
> +#endif
>
> if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
> pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n");
> --
> 2.25.1
>

2023-01-30 17:27:38

by Paul E. McKenney

Subject: Re: [PATCH] rcu: Register rcu-lazy shrinker only CONFIG_RCU_LAZY is enabled

On Mon, Jan 30, 2023 at 10:00:42AM -0500, Joel Fernandes wrote:
> On Mon, Jan 30, 2023 at 2:12 AM Zqiang <[email protected]> wrote:
> >
> > The rcu-lazy shrinker is registered without CONFIG_RCU_LAZY enabled
> > is meaningless, this commit therefore make rcu-lazy shrinker is
> > registered only when CONFIG_RCU_LAZY is enabled.
> >
> > Signed-off-by: Zqiang <[email protected]>
>
> Reviewed-by: Joel Fernandes (Google) <[email protected]>

Queued and pushed, thank you both!

Twice, actually. I missed Joel's reviewed-by the first time around,
fixed now.

Thanx, Paul

> Thanks.
>
> > ---
> > kernel/rcu/tree_nocb.h | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
> > index 9e1c8caec5ce..28c1c092817b 100644
> > --- a/kernel/rcu/tree_nocb.h
> > +++ b/kernel/rcu/tree_nocb.h
> > @@ -1312,6 +1312,7 @@ int rcu_nocb_cpu_offload(int cpu)
> > }
> > EXPORT_SYMBOL_GPL(rcu_nocb_cpu_offload);
> >
> > +#ifdef CONFIG_RCU_LAZY
> > static unsigned long
> > lazy_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
> > {
> > @@ -1360,6 +1361,7 @@ static struct shrinker lazy_rcu_shrinker = {
> > .batch = 0,
> > .seeks = DEFAULT_SEEKS,
> > };
> > +#endif
> >
> > void __init rcu_init_nohz(void)
> > {
> > @@ -1391,8 +1393,10 @@ void __init rcu_init_nohz(void)
> > if (!rcu_state.nocb_is_setup)
> > return;
> >
> > +#ifdef CONFIG_RCU_LAZY
> > if (register_shrinker(&lazy_rcu_shrinker, "rcu-lazy"))
> > pr_err("Failed to register lazy_rcu shrinker!\n");
> > +#endif
> >
> > if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
> > pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n");
> > --
> > 2.25.1
> >