The following commit has been merged into the core/rcu branch of tip:
Commit-ID: 7308e0240410d3644c9d7cc6263079a58e3effeb
Gitweb:
https://git.kernel.org/tip/7308e0240410d3644c9d7cc6263079a58e3effeb
Author: Paul E. McKenney <paul...@kernel.org>
AuthorDate: Wed, 27 Jan 2021 13:57:16 -08:00
Committer: Paul E. McKenney <paul...@kernel.org>
CommitterDate: Mon, 08 Mar 2021 14:21:41 -08:00
rcu: Make rcu_read_unlock_special() expedite strict grace periods
In kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y, every grace
period is an expedited grace period. However, rcu_read_unlock_special()
does not treat them that way, instead allowing the deferred quiescent
state to be reported whenever. This commit therefore adds a check of
this Kconfig option that causes rcu_read_unlock_special() to treat all
grace periods as expedited for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
Signed-off-by: Paul E. McKenney <paul...@kernel.org>
---
kernel/rcu/tree_plugin.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index e17cb23..a21c41c 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -615,6 +615,7 @@ static void rcu_read_unlock_special(struct task_struct *t)
expboost = (t->rcu_blocked_node &&
READ_ONCE(t->rcu_blocked_node->exp_tasks)) ||
(rdp->grpmask & READ_ONCE(rnp->expmask)) ||
+ IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) ||
(IS_ENABLED(CONFIG_RCU_BOOST) && irqs_were_disabled
&&
t->rcu_blocked_node);
// Need to defer quiescent state until everything is enabled.
