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From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Petr Mladek <pmladek@suse.com>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	jack@suse.com, tj@kernel.org, kyle@kernel.org,
	davej@codemonkey.org.uk, calvinowens@fb.com,
	akpm@linux-foundation.org, linux-mm@kvack.org, mhocko@kernel.org
Subject: Re: How to avoid printk() delay caused by cond_resched() ?
Date: Thu, 3 Mar 2016 14:41:24 +0900	[thread overview]
Message-ID: <20160303054124.GA411@swordfish> (raw)
In-Reply-To: <20160302160437.GA2307@quack.suse.cz>

On (03/02/16 17:04), Jan Kara wrote:
> On Wed 02-03-16 23:34:15, Sergey Senozhatsky wrote:
> > > I am looking forward to have the console printing offloaded
> > > into the workqueues. Then printk() will become consistently
> > > "fast" operation and will cause less surprises like this.
> > 
> > I'm all for it. I need this rework badly. If Jan is too busy at
> > the moment, which I surely can understand, then I'll be happy to
> > help ("pick up the patches". please, don't get me wrong).
> 
> So I'm rather busy with other stuff currently so if you can pick up my
> patches and finish them, it would be good. I think I have addressed all the
> comments you had to the previous version, except for handling the case
> where all the workers are too busy - maybe using a dedicated workqueue with
> a rescueue worker instead of system_wq would solve this issue.
> 
> I've sent the current version of patches I have to you including the patch
> 3/3 which I use for debugging and testing whether the async printing really
> helps avoiding softlockups.

great, thank you! will take a look.

and yes, I was thinking about using printk's own workqueue with a
rescue thread bit set (Petr Mladek also proposed this).

	-ss

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  reply	other threads:[~2016-03-03  5:40 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-02 12:01 How to avoid printk() delay caused by cond_resched() ? Tetsuo Handa
2016-03-02 13:38 ` Petr Mladek
2016-03-02 14:11   ` Tetsuo Handa
2016-03-02 15:21     ` Petr Mladek
2016-03-02 14:34   ` Sergey Senozhatsky
2016-03-02 14:56     ` Petr Mladek
2016-03-02 16:04     ` Jan Kara
2016-03-03  5:41       ` Sergey Senozhatsky [this message]
2016-03-02 14:04 ` Sergey Senozhatsky
2016-03-02 15:02   ` Tetsuo Handa
2016-03-02 15:29     ` Sergey Senozhatsky

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