Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup

Tejun Heo
2018-01-10T19:06:01Z

Hello,

On Wed, Jan 10, 2018 at 07:41:44PM +0100, Peter Zijlstra wrote:
> Typically we (scheduler) have removed printk()s (on boot) when BIGSMP
> folks say it creates boot pain. Much of it is now behind the sched_debug
> parameter, others are compressed.
>
> I've also seen other people reduce printk()s.
>
> In general reducing printk() is a good thing, its a low bandwidth
> channel for critical stuff like OOPSen and the like.

Yeah, sure, no disagreement there. It's just that this is a provision
for when that breaks down. In the described scenario, it's also not
caused by any particular one printing too many messages. OOM is just
printing OOM info and packet tx is just printing standard alloc failed
message (and some other following errors). It's the feedback loop
which kills the machine.

Thanks.

--
tejun