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 <paulmck@xxxxxxxxxx> AuthorDate: Wed, 27 Jan 2021 13:57:16 -08:00 Committer: Paul E. McKenney <paulmck@xxxxxxxxxx> 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 <paulmck@xxxxxxxxxx> --- 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.
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