On Wed, May 13, 2020 at 06:47:10PM +0200, Frederic Weisbecker wrote: > This will be necessary to correctly implement rdp de-offloading. We > don't want rcu_do_batch() in nocb_cb kthread to race with local > rcu_do_batch(). > > Signed-off-by: Frederic Weisbecker <[email protected]> > Cc: Paul E. McKenney <[email protected]> > Cc: Josh Triplett <[email protected]> > Cc: Steven Rostedt <[email protected]> > Cc: Mathieu Desnoyers <[email protected]> > Cc: Lai Jiangshan <[email protected]> > Cc: Joel Fernandes <[email protected]>
Reviewed-by: Joel Fernandes (Google) <[email protected]> thanks, - Joel > --- > kernel/rcu/tree_plugin.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h > index 1dd3fdd675a1..43ecc047af26 100644 > --- a/kernel/rcu/tree_plugin.h > +++ b/kernel/rcu/tree_plugin.h > @@ -2104,7 +2104,9 @@ static void nocb_cb_wait(struct rcu_data *rdp) > if (needwake_gp) > rcu_gp_kthread_wake(); > swait_event_interruptible_exclusive(rdp->nocb_cb_wq, > - !READ_ONCE(rdp->nocb_cb_sleep)); > + !READ_ONCE(rdp->nocb_cb_sleep) || > + kthread_should_park()); > + > if (!smp_load_acquire(&rdp->nocb_cb_sleep)) { /* VVV */ > /* ^^^ Ensure CB invocation follows _sleep test. */ > return; > @@ -2125,6 +2127,8 @@ static int rcu_nocb_cb_kthread(void *arg) > // if there are no more ready callbacks, waits for them. > for (;;) { > nocb_cb_wait(rdp); > + if (kthread_should_park()) > + kthread_parkme(); > cond_resched_tasks_rcu_qs(); > } > return 0; > -- > 2.25.0 >
