diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2021-02-23 01:10:10 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-05-12 12:10:23 -0700 |
| commit | 870905169da8bfae0570df013efe860d33251b0f (patch) | |
| tree | 45e8e8ddee84a97c8dbec50150bdf845fe28c7f6 /kernel/rcu/tree.c | |
| parent | f9fc166b790bd214083035d865653133b8a963d1 (diff) | |
| download | linux-870905169da8bfae0570df013efe860d33251b0f.tar.gz linux-870905169da8bfae0570df013efe860d33251b0f.tar.xz | |
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.c')
| -rw-r--r-- | kernel/rcu/tree.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8e78b2430c16..5f1545aab9ed 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3911,7 +3911,7 @@ static int rcu_pending(int user) check_cpu_stall(rdp); /* Does this CPU need a deferred NOCB wakeup? */ - if (rcu_nocb_need_deferred_wakeup(rdp)) + if (rcu_nocb_need_deferred_wakeup(rdp, RCU_NOCB_WAKE)) return 1; /* Is this a nohz_full CPU in userspace or idle? (Ignore RCU if so.) */ |