Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1352831

Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async

From Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Newsgroups linux.kernel
Subject Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async
Date 2016-03-08 11:30 +0100
Message-ID <ran3Q-80x-11@gated-at.bofh.it> (permalink)
References (5 earlier) <ra0qC-1wR-25@gated-at.bofh.it> <ra13k-1LB-13@gated-at.bofh.it> <ra2iK-2IY-11@gated-at.bofh.it> <ra56X-4wc-35@gated-at.bofh.it> <ra5JE-4Li-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

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

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-05 12:00 +0100
  Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-06 07:40 +0100
    Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-03-06 08:20 +0100
      Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-06 10:40 +0100
        Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-03-06 12:10 +0100
          Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-06 14:30 +0100
            Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-03-06 16:00 +0100
            Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Jan Kara <jack@suse.cz> - 2016-03-07 09:30 +0100
              Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-07 11:20 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Jan Kara <jack@suse.cz> - 2016-03-07 12:00 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Jan Kara <jack@suse.cz> - 2016-03-07 13:20 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-03-07 13:40 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-07 16:20 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tejun Heo <tj@kernel.org> - 2016-03-07 17:00 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-08 11:30 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tejun Heo <tj@kernel.org> - 2016-03-11 18:30 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-12 06:10 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-09 07:10 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Jan Kara <jack@suse.cz> - 2016-03-10 10:30 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-10 17:00 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Petr Mladek <pmladek@suse.com> - 2016-03-10 11:00 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-10 17:30 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-07 15:50 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-03-07 12:20 +0100
                Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-07 15:40 +0100
              Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async Tejun Heo <tj@kernel.org> - 2016-03-07 16:50 +0100

csiph-web