linux-kernel - Re: [RFC][PATCH v6 0/2] printk: Make printk() completely async

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Message-ID: <20160423194019.GB15755@amd>
Date:	Sat, 23 Apr 2016 21:40:19 +0200
From:	Pavel Machek <pavel@....cz>
To:	Jan Kara <jack@...e.cz>
Cc:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jan Kara <jack@...e.com>, Petr Mladek <pmladek@...e.com>,
	Tejun Heo <tj@...nel.org>,
	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
	linux-kernel@...r.kernel.org,
	Byungchul Park <byungchul.park@....com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Subject: Re: [RFC][PATCH v6 0/2] printk: Make printk() completely async

On Tue 2016-03-22 07:49:48, Jan Kara wrote:
> Hi,
> 
> On Tue 22-03-16 02:25:28, Sergey Senozhatsky wrote:
> >  The patch set is based on slightly updated Jan Kara's patches.
> > 
> > This patch set makes printk() completely asynchronous: new messages
> > are getting upended to the kernel printk buffer, but instead of 'direct'
> > printing the actual print job is performed by a dedicated kthread.
> > This has the advantage that printing always happens from a schedulable
> > context and thus we don't lockup any particular CPU or even interrupts.
> > 
> > The patch set is against next-20160321
> > 
> > the series in total has 3 patches:
> > - printk: Make printk() completely async
> > - printk: Make wake_up_klogd_work_func() async
> > - printk: make console_unlock() async
> > 
> > per discussion, "printk: make console_unlock() async" will be posted
> > later on.
> 
> Patches look good to me. I don't think you need to mention the
> console_unlock() async patch when it is not part of the series.  BTW, you
> seemed to have dropped my patch to skip if there are too many buffered
> messages when oops is in progress. Any reason for that?

So... from basically linux 0.0, cli() printk("") could be used for
debugging. ... and that's now gone. Right?

Can you explain why that is good idea?
									Pavel
-- 
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