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Re: [RFC][PATCH v9 1/2] printk: Make printk() completely async

From Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Newsgroups linux.kernel
Subject Re: [RFC][PATCH v9 1/2] printk: Make printk() completely async
Date 2016-04-01 18:50 +0200
Message-ID <rjaqJ-7af-1@gated-at.bofh.it> (permalink)
References <rj85A-5zZ-3@gated-at.bofh.it> <rj85A-5zZ-1@gated-at.bofh.it> <rj8RY-6cF-27@gated-at.bofh.it>
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On (04/01/16 17:00), Petr Mladek wrote:
> You need to move this assigment right above the console_lock()/console_unlock()
> calls. Otherwise, there is a race:
> 
> CPU0:				CPU1
> 
> printk_kthread_func()
> 
>   console_unlock()
> 
> 				printk()
> 
> 				printk_kthread_need_flush_console = true;
> 				wake_up_process(printk_kthread);
> 
>   printk_kthread_need_flush_console = false;
> 
>   set_current_state(TASK_INTERRUPTIBLE);
>   if (!printk_kthread_need_flush_console)
>     schedule();

thanks. yeah, this can add latency to some messages.

	-ss

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Thread

[RFC][PATCH v9 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-04-01 16:20 +0200
  Re: [RFC][PATCH v9 1/2] printk: Make printk() completely async Petr Mladek <pmladek@suse.com> - 2016-04-01 17:10 +0200
    Re: [RFC][PATCH v9 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-04-01 18:50 +0200
  Re: [RFC][PATCH v9 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-04-01 18:40 +0200

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