Messages in this thread | | | Date | Tue, 21 Jun 2022 11:30:39 +0530 | Subject | Re: [PATCH rcu 04/12] rcu: Immediately boost preempted readers for strict grace periods | From | Neeraj Upadhyay <> |
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On 6/21/2022 3:50 AM, Paul E. McKenney wrote: > From: Zqiang <qiang1.zhang@intel.com> > > The intent of the CONFIG_RCU_STRICT_GRACE_PERIOD Konfig option is to > cause normal grace periods to complete quickly in order to better catch > errors resulting from improperly leaking pointers from RCU read-side > critical sections. However, kernels built with this option enabled still > wait for some hundreds of milliseconds before boosting RCU readers that > have been preempted within their current critical section. The value > of this delay is set by the CONFIG_RCU_BOOST_DELAY Kconfig option, > which defaults to 500 milliseconds. > > This commit therefore causes kernels build with strict grace periods > to ignore CONFIG_RCU_BOOST_DELAY. This causes rcu_initiate_boost() > to start boosting immediately after all CPUs on a given leaf rcu_node > structure have passed through their quiescent states. > > Signed-off-by: Zqiang <qiang1.zhang@intel.com> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > ---
Reviewed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Thanks Neeraj
> kernel/rcu/tree_plugin.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h > index 440d9e02a26e0..53d05eb804121 100644 > --- a/kernel/rcu/tree_plugin.h > +++ b/kernel/rcu/tree_plugin.h > @@ -1140,7 +1140,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags) > (rnp->gp_tasks != NULL && > rnp->boost_tasks == NULL && > rnp->qsmask == 0 && > - (!time_after(rnp->boost_time, jiffies) || rcu_state.cbovld))) { > + (!time_after(rnp->boost_time, jiffies) || rcu_state.cbovld || > + IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)))) { > if (rnp->exp_tasks == NULL) > WRITE_ONCE(rnp->boost_tasks, rnp->gp_tasks); > raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
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