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authorPaul E. McKenney <paulmck@kernel.org>2022-07-29 01:37:05 +0300
committerPaul E. McKenney <paulmck@kernel.org>2022-08-31 15:08:07 +0300
commit91a967fd6934abc0c7e4b0d26728e38674278707 (patch)
treef713b1173e8d3a19a68e645a5a8dc2b2f0eefbf7 /include/linux/rcutree.h
parent568035b01cfb107af8d2e4bd2fb9aea22cf5b868 (diff)
downloadlinux-91a967fd6934abc0c7e4b0d26728e38674278707.tar.xz
rcu: Add full-sized polling for get_completed*() and poll_state*()
The get_completed_synchronize_rcu() and poll_state_synchronize_rcu() APIs compress 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 first members of the full-state RCU grace-period polling API, namely the get_completed_synchronize_rcu_full() and poll_state_synchronize_rcu_full() functions. These use up to three times the storage (rcu_gp_oldstate structure instead of unsigned long), but which are guaranteed not to miss grace periods, at least in situations where the single-CPU grace-period optimization does not apply. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/rcutree.h')
-rw-r--r--include/linux/rcutree.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 47eaa4cb0df7..4ccbc3aa9dc2 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -40,11 +40,19 @@ bool rcu_eqs_special_set(int cpu);
void rcu_momentary_dyntick_idle(void);
void kfree_rcu_scheduler_running(void);
bool rcu_gp_might_be_stalled(void);
+
+struct rcu_gp_oldstate {
+ unsigned long rgos_norm;
+ unsigned long rgos_exp;
+ unsigned long rgos_polled;
+};
+
unsigned long start_poll_synchronize_rcu_expedited(void);
void cond_synchronize_rcu_expedited(unsigned long oldstate);
unsigned long get_state_synchronize_rcu(void);
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);
void cond_synchronize_rcu(unsigned long oldstate);
bool rcu_is_idle_cpu(int cpu);