[PATCH v2 4/5] kvfree_rcu: Update "monitor_todo" once a batch is started

From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
	"Paul E . McKenney" <paulmck@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Daniel Axtens <dja@axtens.net>,
	Frederic Weisbecker <frederic@kernel.org>,
	Neeraj Upadhyay <neeraju@codeaurora.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Theodore Y . Ts'o" <tytso@mit.edu>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Uladzislau Rezki <urezki@gmail.com>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: [PATCH v2 4/5] kvfree_rcu: Update "monitor_todo" once a batch is started
Date: Thu, 15 Apr 2021 19:19:59 +0200	[thread overview]
Message-ID: <20210415172000.15086-5-urezki@gmail.com> (raw)
In-Reply-To: <20210415172000.15086-1-urezki@gmail.com>

Before attempting of starting a new batch a "monitor_todo" var.
is set to "false" and set back to "true" when a previous RCU
batch is still in progress.

Drop it to "false" only when a new batch has been successfully
queued, if not, it stays active anyway. There is no reason in
setting it force and back.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
 kernel/rcu/tree.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 3ddc9dc97487..17c128d93825 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3415,15 +3415,14 @@ static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp,
 					  unsigned long flags)
 {
 	// Attempt to start a new batch.
-	krcp->monitor_todo = false;
 	if (queue_kfree_rcu_work(krcp)) {
 		// Success! Our job is done here.
+		krcp->monitor_todo = false;
 		raw_spin_unlock_irqrestore(&krcp->lock, flags);
 		return;
 	}
 
 	// Previous RCU batch still in progress, try again later.
-	krcp->monitor_todo = true;
 	schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
 	raw_spin_unlock_irqrestore(&krcp->lock, flags);
 }
-- 
2.20.1

