Re: [printk] fbc14616f4: BUG:kernel_reboot-without-warning_in_test_stage

From: Pavel Machek <pavel@ucw.cz>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>, Jan Kara <jack@suse.cz>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Ye Xiaolong <xiaolong.ye@intel.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>, Len Brown <len.brown@intel.com>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [printk]  fbc14616f4: BUG:kernel_reboot-without-warning_in_test_stage
Date: Wed, 12 Apr 2017 20:43:20 +0200	[thread overview]
Message-ID: <20170412184320.GC18640@amd> (raw)
In-Reply-To: <20170411161953.GA447@tigerII.localdomain>

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On Wed 2017-04-12 01:19:53, Sergey Senozhatsky wrote:
> On (04/11/17 10:46), Sergey Senozhatsky wrote:
> > On (04/10/17 20:48), Pavel Machek wrote:
> > [..]
> > > > but, once again, I see your point.
> > > 
> > > Good. Does that mean that the next version of patches will work ok in
> > > that case?
> > 
> > yes.
> 
> ok... so I'm looking at something like below right now.
> not really tested yet.
> 
> I put some comments into the code.
> 
> it does offloading after X printed lines by the same process.
> if we reschedule, then the counter resets. which is probably OK,
> we don't really want any process, except for printk_kthread, to
> stay in console_unlock() forever. "number of lines printed" is
> probably easier to understand (easily converted to the number of
> pageup/pagedown you need to press, terminal buffer history size,
> etc.) than seconds we spent on printing (which doesn't even
> correspond to messages' timestamps in general case).

Design looks good to me... certainly better than previous version :-).

> when the limit of "number of lines printed" is 0, then no
> offloading takes place.

And with "number of lines printed" set to 999999, it will get us
previous behaviour, right? 

Thanks,
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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