linux-kernel - [PATCH] kthread: Use TASK_IDLE state for newly created kernel threads

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Message-Id: <1589975710-9283-1-git-send-email-pkondeti@codeaurora.org>
Date:   Wed, 20 May 2020 17:25:09 +0530
From:   Pavankumar Kondeti <pkondeti@...eaurora.org>
To:     linux-kernel@...r.kernel.org
Cc:     Vinayak Menon <vinmenon@...eaurora.org>,
        Pavankumar Kondeti <pkondeti@...eaurora.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Ben Dooks <ben.dooks@...ethink.co.uk>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Liang Chen <cl@...k-chips.com>
Subject: [PATCH] kthread: Use TASK_IDLE state for newly created kernel threads

When kernel threads are created for later use, they will be in
TASK_UNINTERRUPTIBLE state until they are woken up. This results
in increased loadavg and false hung task reports. To fix this,
use TASK_IDLE state instead of TASK_UNINTERRUPTIBLE when
a kernel thread schedules out for the first time.

Signed-off-by: Pavankumar Kondeti <pkondeti@...eaurora.org>
---
 kernel/kthread.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index bfbfa48..b74ed8e 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -250,7 +250,7 @@ static int kthread(void *_create)
 	current->vfork_done = &self->exited;
 
 	/* OK, tell user we're spawned, wait for stop or wakeup */
-	__set_current_state(TASK_UNINTERRUPTIBLE);
+	__set_current_state(TASK_IDLE);
 	create->result = current;
 	/*
 	 * Thread is going to call schedule(), do not preempt it,
@@ -428,7 +428,7 @@ static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state)
 
 void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask)
 {
-	__kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE);
+	__kthread_bind_mask(p, mask, TASK_IDLE);
 }
 
 /**
@@ -442,7 +442,7 @@ void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask)
  */
 void kthread_bind(struct task_struct *p, unsigned int cpu)
 {
-	__kthread_bind(p, cpu, TASK_UNINTERRUPTIBLE);
+	__kthread_bind(p, cpu, TASK_IDLE);
 }
 EXPORT_SYMBOL(kthread_bind);
 
-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.