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| author | Frederic Weisbecker <frederic@kernel.org> | 2021-02-23 01:10:10 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-05-12 21:10:23 +0200 |
| commit | 870905169da8bfae0570df013efe860d33251b0f (patch) | |
| tree | 45e8e8ddee84a97c8dbec50150bdf845fe28c7f6 /kernel/rcu/tree.h | |
| parent | rcu/nocb: Only cancel nocb timer if not polling (diff) | |
| download | linux-870905169da8bfae0570df013efe860d33251b0f.tar.xz linux-870905169da8bfae0570df013efe860d33251b0f.zip | |
rcu/nocb: Prepare for fine-grained deferred wakeup
Tuning the deferred wakeup level must be done from a safe wakeup
point. Currently those sites are:
* ->nocb_timer
* user/idle/guest entry
* CPU down
* softirq/rcuc
All of these sites perform the wake up for both RCU_NOCB_WAKE and
RCU_NOCB_WAKE_FORCE.
In order to merge ->nocb_timer and ->nocb_bypass_timer together, we plan
to add a new RCU_NOCB_WAKE_BYPASS that really should be deferred until
a timer fires so that we don't wake up the NOCB-gp kthread too early.
To prepare for that, this commit specifies the per-callsite wakeup
level/limit.
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
[ paulmck: Fix non-NOCB rcu_nocb_need_deferred_wakeup() definition. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index b280a843bd2c..2510e86265c1 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -433,7 +433,7 @@ static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp, bool *was_alldone, unsigned long flags); static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty, unsigned long flags); -static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); +static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level); static bool do_nocb_deferred_wakeup(struct rcu_data *rdp); static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); static void rcu_spawn_cpu_nocb_kthread(int cpu); |