[External] Re: [PATCH 2/2] sched: mark PRINTK_DEFERRED_CONTEXT_MASK in __schedule()

[Sergey Senozhatsky]

On (20/09/28 12:25), Peter Zijlstra wrote:
[..]
> > printk
> >   vprintk_emit
> >     console_unlock
> >       vt_console_print
> >         hide_cursor
> >           bit_cursor
> >             soft_cursor
> >               queue_work_on
> >                 __queue_work
> >                   try_to_wake_up
> >                     _raw_spin_lock
> >                       native_queued_spin_lock_slowpath
> > 
> > Looks like it's introduced by this commit:
> > 
> > eaa434defaca1781fb2932c685289b610aeb8b4b
> > 
> > "drm/fb-helper: Add fb_deferred_io support"
> 
> Oh gawd, yeah, all the !serial consoles are utter batshit.
> 
> Please look at John's last printk rewrite, IIRC it farms all that off to
> a kernel thread instead of doing it from the printk() caller's context.

Not yet. Scheduler is still part of the printk() - either in the
form of !serial consoles or console_sem, or both.

	-ss