From 3fdefca9b42c8bebe3beea5c1a067c9718ca0fc7 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 28 Jul 2022 19:58:13 -0700 Subject: rcu: Add full-sized polling for get_state() The get_state_synchronize_rcu() API compresses the combined expedited and normal grace-period states into a single unsigned long, which conserves storage, but can miss grace periods in certain cases involving overlapping normal and expedited grace periods. Missing the occasional grace period is usually not a problem, but there are use cases that care about each and every grace period. This commit therefore adds the next member of the full-state RCU grace-period polling API, namely the get_state_synchronize_rcu_full() function. This uses up to three times the storage (rcu_gp_oldstate structure instead of unsigned long), but is guaranteed not to miss grace periods. Signed-off-by: Paul E. McKenney --- include/linux/rcutree.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/rcutree.h') diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 4ccbc3aa9dc2..7b769f1b417a 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -50,6 +50,7 @@ struct rcu_gp_oldstate { unsigned long start_poll_synchronize_rcu_expedited(void); void cond_synchronize_rcu_expedited(unsigned long oldstate); unsigned long get_state_synchronize_rcu(void); +void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp); unsigned long start_poll_synchronize_rcu(void); bool poll_state_synchronize_rcu(unsigned long oldstate); bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp); -- cgit v1.2.3-59-g8ed1b