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authorLai Jiangshan <laijs@linux.alibaba.com>2019-11-01 05:06:21 -0700
committerPaul E. McKenney <paulmck@kernel.org>2020-01-24 10:27:33 -0800
commit3717e1e9f25ec7059e421ab6fc602cab7063c11c (patch)
treee3be4d9999576967141e14a0ade78330474d36e1 /kernel/rcu
parentrcu: Clear .exp_hint only when deferred quiescent state has been reported (diff)
downloadlinux-dev-3717e1e9f25ec7059e421ab6fc602cab7063c11c.tar.xz
linux-dev-3717e1e9f25ec7059e421ab6fc602cab7063c11c.zip
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 <laijs@linux.alibaba.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree_plugin.h19
1 files changed, 3 insertions, 16 deletions
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