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rcu: Make rcu_read_unlock_special() expedite strict grace periods

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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@kernel.org>
This commit is contained in:
Paul E. McKenney 2021-01-27 13:57:16 -08:00
parent 5e59fba573
commit 7308e02404
1 changed files with 1 additions and 0 deletions
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kernel/rcu/tree_plugin.h
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@ -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.