From: Lai Jiangshan Date: Fri, 1 Nov 2019 12:06:21 +0000 (-0700) Subject: rcu: Clear ->rcu_read_unlock_special only once X-Git-Tag: v5.6-rc1~134^2~1^6~3 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=3717e1e9f25ec7059e421ab6fc602cab7063c11c;p=linux.git rcu: Clear ->rcu_read_unlock_special only once In rcu_preempt_deferred_qs_irqrestore(), ->rcu_read_unlock_special is cleared one piece at a time. Given that the "if" statements in this function use the copy in "special", this commit removes the clearing of the individual pieces in favor of clearing ->rcu_read_unlock_special in one go just after it has been determined to be non-zero. Signed-off-by: Lai Jiangshan Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 7487c7930a47..c3a32717c42d 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -444,16 +444,9 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) local_irq_restore(flags); return; } - t->rcu_read_unlock_special.b.exp_hint = false; - t->rcu_read_unlock_special.b.deferred_qs = false; - if (special.b.need_qs) { + t->rcu_read_unlock_special.s = 0; + if (special.b.need_qs) rcu_qs(); - t->rcu_read_unlock_special.b.need_qs = false; - if (!t->rcu_read_unlock_special.s && !rdp->exp_deferred_qs) { - local_irq_restore(flags); - return; - } - } /* * Respond to a request by an expedited grace period for a @@ -461,17 +454,11 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) * tasks are handled when removing the task from the * blocked-tasks list below. */ - if (rdp->exp_deferred_qs) { + if (rdp->exp_deferred_qs) rcu_report_exp_rdp(rdp); - if (!t->rcu_read_unlock_special.s) { - local_irq_restore(flags); - return; - } - } /* Clean up if blocked during RCU read-side critical section. */ if (special.b.blocked) { - t->rcu_read_unlock_special.b.blocked = false; /* * Remove this task from the list it blocked on. The task