From: Zqiang <qiang.zhang1211@gmail.com>
To: paulmck@kernel.org, frederic@kernel.org, joel@joelfernandes.org,
boqun.feng@gmail.com
Cc: qiang.zhang1211@gmail.com, rcu@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] rcu: Force quiescent states only for ongoing grace period
Date: Wed, 1 Nov 2023 11:35:07 +0800 [thread overview]
Message-ID: <20231101033507.21651-1-qiang.zhang1211@gmail.com> (raw)
Currently, when running the rcutorture testing, if the fqs_task
kthread was created, the periodic fqs operations will be performed,
regardless of whether the grace-period is ongoing. however, if there
is no ongoing grace-period, invoke the rcu_force_quiescent_state() has
no effect, because when the new grace-period starting, will clear all
flags int rcu_state.gp_flags in rcu_gp_init(). this commit therefore add
rcu_gp_in_progress() check in rcu_force_quiescent_state(), if there is
no ongoing grace-period, return directly.
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
---
kernel/rcu/tree.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index aa4c808978b8..5b4279ef66da 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2338,6 +2338,8 @@ void rcu_force_quiescent_state(void)
struct rcu_node *rnp;
struct rcu_node *rnp_old = NULL;
+ if (!rcu_gp_in_progress())
+ return;
/* Funnel through hierarchy to reduce memory contention. */
rnp = raw_cpu_read(rcu_data.mynode);
for (; rnp != NULL; rnp = rnp->parent) {
--
2.17.1
next reply other threads:[~2023-11-01 3:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-01 3:35 Zqiang [this message]
2023-11-03 2:54 ` [PATCH] rcu: Force quiescent states only for ongoing grace period Paul E. McKenney
2023-11-03 7:14 ` Z qiang
2023-11-03 18:06 ` Paul E. McKenney
2023-11-07 6:30 ` Z qiang
2023-11-07 16:53 ` Paul E. McKenney
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