linux-kernel - [PATCH 6/6] kvfree_rcu: use kfree_rcu_monitor() instead of open-coded variant

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Date:   Wed, 14 Apr 2021 14:12:26 +0200
From:   "Uladzislau Rezki (Sony)" <urezki@...il.com>
To:     LKML <linux-kernel@...r.kernel.org>, RCU <rcu@...r.kernel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>
Cc:     Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Daniel Axtens <dja@...ens.net>,
        Frederic Weisbecker <frederic@...nel.org>,
        Neeraj Upadhyay <neeraju@...eaurora.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Theodore Y . Ts'o" <tytso@....edu>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Uladzislau Rezki <urezki@...il.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>
Subject: [PATCH 6/6] kvfree_rcu: use kfree_rcu_monitor() instead of open-coded variant

To queue a new batch we have a kfree_rcu_monitor() function that
checks KRC_MONITOR_TODO bit and invokes kfree_rcu_drain_unlock()
to start a new batch after a GP. Get rid of open-coded case by
switching it to the separate function.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
 kernel/rcu/tree.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 012030cbe55e..14e9220198eb 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3680,7 +3680,6 @@ static unsigned long
 kfree_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 {
 	int cpu, freed = 0;
-	unsigned long flags;
 
 	for_each_possible_cpu(cpu) {
 		int count;
@@ -3688,12 +3687,7 @@ kfree_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 
 		count = krcp->count;
 		count += drain_page_cache(krcp);
-
-		raw_spin_lock_irqsave(&krcp->lock, flags);
-		if (test_bit(KRC_MONITOR_TODO, &krcp->flags))
-			kfree_rcu_drain_unlock(krcp, flags);
-		else
-			raw_spin_unlock_irqrestore(&krcp->lock, flags);
+		kfree_rcu_monitor(&krcp->monitor_work.work);
 
 		sc->nr_to_scan -= count;
 		freed += count;
-- 
2.20.1