From d96c52fe4907c68adc5e61a0bef7aec0933223d5 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 15 Apr 2022 10:55:42 -0700 Subject: rcu: Add polled expedited grace-period primitives This commit adds expedited grace-period functionality to RCU's polled grace-period API, adding start_poll_synchronize_rcu_expedited() and cond_synchronize_rcu_expedited(), which are similar to the existing start_poll_synchronize_rcu() and cond_synchronize_rcu() functions, respectively. Note that although start_poll_synchronize_rcu_expedited() can be invoked very early, the resulting expedited grace periods are not guaranteed to start until after workqueues are fully initialized. On the other hand, both synchronize_rcu() and synchronize_rcu_expedited() can also be invoked very early, and the resulting grace periods will be taken into account as they occur. [ paulmck: Apply feedback from Neeraj Upadhyay. ] Link: https://lore.kernel.org/all/20220121142454.1994916-1-bfoster@redhat.com/ Link: https://docs.google.com/document/d/1RNKWW9jQyfjxw2E8dsXVTdvZYh0HnYeSHDKog9jhdN8/edit?usp=sharing Cc: Brian Foster Cc: Dave Chinner Cc: Al Viro Cc: Ian Kent Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 10 ++++++++++ include/linux/rcutree.h | 2 ++ 2 files changed, 12 insertions(+) (limited to 'include') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 5fed476f977f..ab7e20dfb07b 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -23,6 +23,16 @@ static inline void cond_synchronize_rcu(unsigned long oldstate) might_sleep(); } +static inline unsigned long start_poll_synchronize_rcu_expedited(void) +{ + return start_poll_synchronize_rcu(); +} + +static inline void cond_synchronize_rcu_expedited(unsigned long oldstate) +{ + cond_synchronize_rcu(oldstate); +} + extern void rcu_barrier(void); static inline void synchronize_rcu_expedited(void) diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 9c6cfb742504..20dbaa9a3882 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -40,6 +40,8 @@ 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); +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); -- cgit v1.2.3