[PATCH v6 15/45] rcu: dynamically allocate the rcu-lazy shrinker

[Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>]

Use new APIs to dynamically allocate the rcu-lazy shrinker.

Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
CC: rcu@xxxxxxxxxxxxxxx
---
 kernel/rcu/tree_nocb.h | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index 5598212d1f27..4efbf7333d4e 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 +1430,15 @@ 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;
+
+		shrinker_register(lazy_rcu_shrinker);
+	}
 #endif // #ifdef CONFIG_RCU_LAZY
 
 	if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
-- 
2.30.2