From 22cf8bc6cb0d48c6d31da8eccbd4201ab9b0c4c6 Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@fb.com>
Date: Thu, 31 Aug 2017 16:15:23 -0700
Subject: [PATCH] kernel/kthread.c: kthread_worker: don't hog the cpu

If the worker thread continues getting work, it will hog the cpu and rcu
stall complains.  Make it a good citizen.  This is triggered in a loop
block device test.

Link: http://lkml.kernel.org/r/5de0a179b3184e1a2183fc503448b0269f24d75b.1503697127.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/kthread.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 26db528c1d88..1c19edf82427 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -637,6 +637,7 @@ int kthread_worker_fn(void *worker_ptr)
 		schedule();
 
 	try_to_freeze();
+	cond_resched();
 	goto repeat;
 }
 EXPORT_SYMBOL_GPL(kthread_worker_fn);