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From: neeraj.upadhyay@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, paulmck@kernel.org,
	joel@joelfernandes.org, frederic@kernel.org,
	boqun.feng@gmail.com, urezki@gmail.com, rostedt@goodmis.org,
	mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
	qiang.zhang1211@gmail.com, peterz@infradead.org,
	neeraj.upadhyay@amd.com,
	Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Subject: [PATCH v2 03/10] rcu/tasks: Move holdout checks for idle task to a separate function
Date: Wed,  9 Oct 2024 18:21:20 +0530	[thread overview]
Message-ID: <20241009125127.18902-4-neeraj.upadhyay@kernel.org> (raw)
In-Reply-To: <20241009125127.18902-1-neeraj.upadhyay@kernel.org>

From: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

Move checks for an idle task being a holdout task for RCU-tasks
to a separate function - rcu_idle_task_is_holdout(). This function
will be used in subsequent commits to add additional checks for
idle task. No functional change intended.

Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
---
 kernel/rcu/tasks.h | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 6333f4ccf024..56015ced3f37 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -976,6 +976,15 @@ static void rcu_tasks_pregp_step(struct list_head *hop)
 	synchronize_rcu();
 }
 
+static bool rcu_idle_task_is_holdout(struct task_struct *t, int cpu)
+{
+	/* Idle tasks on offline CPUs are RCU-tasks quiescent states. */
+	if (!rcu_cpu_online(cpu))
+		return false;
+
+	return true;
+}
+
 /* Check for quiescent states since the pregp's synchronize_rcu() */
 static bool rcu_tasks_is_holdout(struct task_struct *t)
 {
@@ -995,9 +1004,8 @@ static bool rcu_tasks_is_holdout(struct task_struct *t)
 
 	cpu = task_cpu(t);
 
-	/* Idle tasks on offline CPUs are RCU-tasks quiescent states. */
-	if (t == idle_task(cpu) && !rcu_cpu_online(cpu))
-		return false;
+	if (t == idle_task(cpu))
+		return rcu_idle_task_is_holdout(t, cpu);
 
 	return true;
 }
-- 
2.40.1


  parent reply	other threads:[~2024-10-09 12:51 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-09 12:51 [PATCH v2 00/10] Make RCU Tasks scan idle tasks neeraj.upadhyay
2024-10-09 12:51 ` [PATCH v2 01/10] rcu: Change rdp arg to cpu number for rcu_watching_snap_stopped_since() neeraj.upadhyay
2024-10-09 12:51 ` [PATCH v2 02/10] rcu: Make some rcu_watching_* functions global neeraj.upadhyay
2024-10-09 12:51 ` neeraj.upadhyay [this message]
2024-10-09 12:51 ` [PATCH v2 04/10] rcu/tasks: Create rcu_idle_task_is_holdout() definition for !SMP neeraj.upadhyay
2024-10-09 12:51 ` [PATCH v2 05/10] rcu/tasks: Consider idle tasks not running on CPU as non-holdouts neeraj.upadhyay
2024-10-09 12:51 ` [PATCH v2 06/10] rcu/tasks: Check RCU watching state for holdout idle tasks neeraj.upadhyay
2024-10-09 12:51 ` [PATCH v2 07/10] rcu/tasks: Check RCU watching state for holdout idle injection tasks neeraj.upadhyay
2024-10-09 14:37   ` Frederic Weisbecker
2024-10-09 12:51 ` [PATCH v2 08/10] rcu/tasks: Make RCU-tasks pay attention to idle tasks neeraj.upadhyay
2024-10-09 12:51 ` [PATCH v2 09/10] context_tracking: Invoke RCU-tasks enter/exit for NMI context neeraj.upadhyay
2024-10-09 12:51 ` [PATCH v2 10/10] rcu: Allow short-circuiting of synchronize_rcu_tasks_rude() neeraj.upadhyay

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