Re: [RFC PATCH] io-wq: kill cpu hog worker

[Hillf Danton <hdanton@sina.com>]

On Mon, 23 Dec 2019 08:15:00 -0700 Jens Axboe wrote:
> 
> On 12/22/19 7:41 PM, Hillf Danton wrote:
> > 
> > Reschedule the current IO worker if it is becoming a cpu hog.
> 
> Might make more sense to put this a bit earlier, to avoid the
> awkward lock juggle. In theory it shouldn't make a difference
> if we do it _before_ doing new work, or _after_ doing work. We
> should only be rescheduling if it's running for quite a while.
> 
> How about putting it after the flushing of signals instead?


All right, thanks.

Hillf
--->8---
From: Hillf Danton <hdanton@sina.com>
Subject: [RFC PATCH] io-wq: kill cpu hog worker

Reschedule the current IO worker to cut the risk that it is becoming
a cpu hog.

Signed-off-by: Hillf Danton <hdanton@sina.com>
---

--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -432,6 +432,8 @@ next:
 		if (signal_pending(current))
 			flush_signals(current);
 
+		cond_resched();
+
 		spin_lock_irq(&worker->lock);
 		worker->cur_work = work;
 		spin_unlock_irq(&worker->lock);
--