All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Jan Kara <jack@suse.cz>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	akpm@linux-foundation.org, jack@suse.com, pmladek@suse.com,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async
Date: Tue, 8 Mar 2016 19:21:52 +0900	[thread overview]
Message-ID: <20160308102152.GB457@swordfish> (raw)
In-Reply-To: <20160307154936.GB7065@htj.duckdns.org>

Hello Tejun,

On (03/07/16 10:49), Tejun Heo wrote:
> On Tue, Mar 08, 2016 at 12:10:47AM +0900, Sergey Senozhatsky wrote:
> > A new version. Switched to [printk] kthread.
> 
> There are some benefits to using a percpu workqueue with CPU_INTENSIVE
> set or an unbound workqueue.  It'd need WQ_RESCUER so it'd still
> create a dedicated thread which is used under heavy memory pressure
> but workqueue will usaully give you local (cpu or node) worker.  One
> reason to use kthread directly tho is minimizing the amount of
> dependency which is pretty important for printk.  If we decide to use
> kthread instead of workqueue, let's please do it for the right reason.

thanks.

I'd personally prefer to go with the "less dependency" option -- a dedicated
kthread, I think. mostly for the sake of simplicity. I agree with the point
that console_unlock() has unpredictable execution time, and in general case
we would have a busy kworker (or sleeping in console_lock() or doing
cond_resched()) and an idle extra WQ_RESCUER kthread, with activation rules
that don't depend on printk. printk with dedicated printk-kthread seems
easier to control. how does it sound?

	-ss

  reply	other threads:[~2016-03-08 10:20 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-05 10:55 [RFC][PATCH v2 0/2] printk: Make printk() completely async Sergey Senozhatsky
2016-03-05 10:55 ` [RFC][PATCH v2 1/2] " Sergey Senozhatsky
2016-03-06  6:32   ` Sergey Senozhatsky
2016-03-06  7:18     ` Tetsuo Handa
2016-03-06  9:35       ` Sergey Senozhatsky
2016-03-06 11:06         ` Tetsuo Handa
2016-03-06 13:27           ` Sergey Senozhatsky
2016-03-06 14:54             ` Tetsuo Handa
2016-03-07  8:22             ` Jan Kara
2016-03-07 10:12               ` Sergey Senozhatsky
2016-03-07 10:52                 ` Jan Kara
2016-03-07 12:16                   ` Jan Kara
2016-03-07 12:37                     ` Tetsuo Handa
2016-03-07 15:10                     ` Sergey Senozhatsky
2016-03-07 15:49                       ` Tejun Heo
2016-03-08 10:21                         ` Sergey Senozhatsky [this message]
2016-03-11 17:22                           ` Tejun Heo
2016-03-12  5:01                             ` Sergey Senozhatsky
2016-03-09  6:09                     ` Sergey Senozhatsky
2016-03-10  9:27                       ` Jan Kara
2016-03-10 15:48                         ` Sergey Senozhatsky
2016-03-10  9:53                       ` Petr Mladek
2016-03-10 16:26                         ` Sergey Senozhatsky
2016-03-07 14:40                   ` Sergey Senozhatsky
2016-03-07 11:10                 ` Tetsuo Handa
2016-03-07 14:36                   ` Sergey Senozhatsky
2016-03-07 15:42               ` Tejun Heo
2016-03-05 10:55 ` [RFC][PATCH v2 2/2] printk: Skip messages on oops Sergey Senozhatsky

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160308102152.GB457@swordfish \
    --to=sergey.senozhatsky.work@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=jack@suse.com \
    --cc=jack@suse.cz \
    --cc=linux-kernel@vger.kernel.org \
    --cc=penguin-kernel@I-love.SAKURA.ne.jp \
    --cc=pmladek@suse.com \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=tj@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.