diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2020-11-13 13:13:22 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-01-06 16:24:25 -0800 |
| commit | 254e11efde66ca0a0ce0c99a62c377314b5984ff (patch) | |
| tree | 0970ebf1028b1033b20d5eb8c28e82c79ce4f688 /include/linux/rcupdate.h | |
| parent | 5bb39dc956f3d4f1bb75b5962b503426c45340ae (diff) | |
rcu/nocb: Re-offload support
To re-offload the callback processing off of a CPU, it is necessary to
clear SEGCBLIST_SOFTIRQ_ONLY, set SEGCBLIST_OFFLOADED, and then notify
both the CB and GP kthreads so that they both set their own bit flag and
start processing the callbacks remotely. The re-offloading worker is
then notified that it can stop the RCU_SOFTIRQ handler (or rcuc kthread,
as the case may be) from processing the callbacks locally.
Ordering must be carefully enforced so that the callbacks that used to be
processed locally without locking will have the same ordering properties
when they are invoked by the nocb CB and GP kthreads.
This commit makes this change.
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Inspired-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
[ paulmck: Export rcu_nocb_cpu_offload(). ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/rcupdate.h')
| -rw-r--r-- | include/linux/rcupdate.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 40266eb418b6..e0ee52e2756d 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -104,9 +104,11 @@ static inline void rcu_user_exit(void) { } #ifdef CONFIG_RCU_NOCB_CPU void rcu_init_nohz(void); +int rcu_nocb_cpu_offload(int cpu); int rcu_nocb_cpu_deoffload(int cpu); #else /* #ifdef CONFIG_RCU_NOCB_CPU */ static inline void rcu_init_nohz(void) { } +static inline int rcu_nocb_cpu_offload(int cpu) { return -EINVAL; } static inline int rcu_nocb_cpu_deoffload(int cpu) { return 0; } #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */ |