Hello, On Wed, Nov 08, 2017 at 02:29:35PM +0900, Sergey Senozhatsky wrote: > > The following is a completely untested patch to show how we can put > > the console in full sync mode, just the general idea. I'm a bit > > skeptical we really wanna do this given that we already (with or > > without the patch) stay sync for most of these events due to the way > > we go async, but, yeah, if we wanna do that, we can do that. > > we've been going in a slightly different direction in printk-kthread. > > we keep printk sync by default [as opposed to previous "immediately > offload" approach]. people asked for it, some people demanded it. we > offload to printk-kthread only when we detect that this particular > task on this particular CPU has been doing printing (without rescheduling) > for 1/2 of watchdog threshold value. IOW, if we see that we are heading > towards the lockup limit then we offload. otherwise - we let it loop in > console_unlock().
FWIW, I'm still a bit skeptical whether that's the right direction. People asking for it doesn't indicate that the flipside isn't worse. Hmm... I think my impression is mostly from the fact that throughout the years I can only count few times where loss of printk messages was an actual issue. The system getting slowed down / locking up from printk message deluge was *far* more prevalent. Thanks. -- tejun
