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>

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 26db528c1d881bf371ea5b53b7ade0815c990bf1..1c19edf824272db47a48730478af5f3b582bbf67 100644 (file)
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -637,6 +637,7 @@ repeat:
                schedule();
 
        try_to_freeze();
+       cond_resched();
        goto repeat;
 }
 EXPORT_SYMBOL_GPL(kthread_worker_fn);