On Wed, Jun 22, 2022 at 10:50:59PM +0000, Joel Fernandes (Google) wrote: > We notice that rcu_barrier() can take a really long time. It appears > that this can happen when all CBs are lazy and the timer does not fire > yet. So after flushing, nothing wakes up GP thread. This patch forces > GP thread to wake when bypass flushing happens, this fixes the > rcu_barrier() delays with lazy CBs. I am wondering if there is a bug in non-rcu_barrier() lazy callback processing hiding here as well? Thanx, Paul > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> > --- > kernel/rcu/tree_nocb.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h > index 2f5da12811a5..b481f1ea57c0 100644 > --- a/kernel/rcu/tree_nocb.h > +++ b/kernel/rcu/tree_nocb.h > @@ -325,6 +325,8 @@ static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp, > rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rcl); > WRITE_ONCE(rdp->nocb_bypass_first, j); > rcu_nocb_bypass_unlock(rdp); > + > + wake_nocb_gp(rdp, true); > return true; > } > > -- > 2.37.0.rc0.104.g0611611a94-goog >
