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[94.245.46.61]) by smtp.gmail.com with ESMTPSA id o16sm730253lfu.228.2021.04.28.06.45.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Apr 2021 06:45:08 -0700 (PDT) From: "Uladzislau Rezki (Sony)" To: LKML , RCU , "Paul E . McKenney" Cc: Michal Hocko , Andrew Morton , Daniel Axtens , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Peter Zijlstra , Thomas Gleixner , "Theodore Y . Ts'o" , Sebastian Andrzej Siewior , Uladzislau Rezki , Oleksiy Avramchenko Subject: [PATCH v1 4/5] kvfree_rcu: Refactor kfree_rcu_monitor() function Date: Wed, 28 Apr 2021 15:44:21 +0200 Message-Id: <20210428134422.1894-4-urezki@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210428134422.1894-1-urezki@gmail.com> References: <20210428134422.1894-1-urezki@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Rearm the monitor work directly from its own function that is kfree_rcu_monitor(). So this patch puts the invocation timing control in one place. Signed-off-by: Uladzislau Rezki (Sony) --- kernel/rcu/tree.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e44d6f8c56f0..229e909ad437 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3415,37 +3415,44 @@ static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp) return !repeat; } -static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp, - unsigned long flags) +/* + * This function queues a new batch. If success or nothing to + * drain it returns 1. Otherwise 0 is returned indicating that + * a reclaim kthread has not processed a previous batch. + */ +static inline int kfree_rcu_drain(struct kfree_rcu_cpu *krcp) { + unsigned long flags; + int ret; + + raw_spin_lock_irqsave(&krcp->lock, flags); + // Attempt to start a new batch. - if (queue_kfree_rcu_work(krcp)) { + ret = queue_kfree_rcu_work(krcp); + if (ret) // 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. - schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); raw_spin_unlock_irqrestore(&krcp->lock, flags); + return ret; } /* * This function is invoked after the KFREE_DRAIN_JIFFIES timeout. - * It invokes kfree_rcu_drain_unlock() to attempt to start another batch. + * It invokes kfree_rcu_drain() to attempt to start another batch. */ static void kfree_rcu_monitor(struct work_struct *work) { - unsigned long flags; struct kfree_rcu_cpu *krcp = container_of(work, struct kfree_rcu_cpu, monitor_work.work); - raw_spin_lock_irqsave(&krcp->lock, flags); - if (krcp->monitor_todo) - kfree_rcu_drain_unlock(krcp, flags); - else - raw_spin_unlock_irqrestore(&krcp->lock, flags); + if (kfree_rcu_drain(krcp)) + return; + + // Not success. A previous batch is still in progress. + // Rearm a work to repeat an attempt of starting another batch. + schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); } static enum hrtimer_restart -- 2.20.1