From: Paul E. McKenney Date: Wed, 27 Jan 2021 21:57:16 +0000 (-0800) Subject: rcu: Make rcu_read_unlock_special() expedite strict grace periods X-Git-Tag: v5.13-rc1~122^2^2^7~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7308e0240410d3644c9d7cc6263079a58e3effeb;p=thirdparty%2Fkernel%2Flinux.git 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 --- diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index e17cb233bfc90..a21c41cc86ad7 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.