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Re: [RFC][PATCHv3 1/5] printk: move printk_pending out of per-cpu

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  Re: [RFC][PATCHv3 1/5] printk: move printk_pending out of per-cpu Petr Mladek <pmladek@suse.com> - 2017-05-25 14:20 +0200
    Re: [RFC][PATCHv3 1/5] printk: move printk_pending out of per-cpu Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-05-25 14:40 +0200
      Re: [RFC][PATCHv3 1/5] printk: move printk_pending out of per-cpu Petr Mladek <pmladek@suse.com> - 2017-05-25 14:50 +0200

#1650445 — Re: [RFC][PATCHv3 1/5] printk: move printk_pending out of per-cpu

On Tue 2017-05-09 17:28:55, Sergey Senozhatsky wrote:
> Do not keep `printk_pending' in per-CPU area. We set the following bits
> of printk_pending:
> a) PRINTK_PENDING_WAKEUP
> 	when we need to wakeup klogd
> b) PRINTK_PENDING_OUTPUT
> 	when there is a pending output from deferred printk and we need
> 	to call console_unlock().
> 
> So none of the bits control/represent a state of a particular CPU and,
> basically, they should be global instead.
> 
> Besides we will use `printk_pending' to control printk kthread, so this
> patch is also a preparation work.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Suggested-by: Petr Mladek <pmladek@suse.com>
> ---
>  kernel/printk/printk.c | 26 ++++++++++++--------------
>  1 file changed, 12 insertions(+), 14 deletions(-)
> 
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index a1aecf44ab07..2cb7f4753b76 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -401,6 +401,14 @@ DEFINE_RAW_SPINLOCK(logbuf_lock);
>  		printk_safe_exit_irqrestore(flags);	\
>  	} while (0)
>  
> +/*
> + * Delayed printk version, for scheduler-internal messages:
> + */
> +#define PRINTK_PENDING_WAKEUP	0x01
> +#define PRINTK_PENDING_OUTPUT	0x02
> +
> +static unsigned long printk_pending;
> +
>  #ifdef CONFIG_PRINTK

The variable is used only when CONFIG_PRINTK is defined at
the moment, so this produces a warning about an unused variable.

Otherwise, the patch looks fine to me.

Best Regards,
Petr

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#1650452

On (05/25/17 14:11), Petr Mladek wrote:
[..]
> The variable is used only when CONFIG_PRINTK is defined at
> the moment, so this produces a warning about an unused variable.
> 

interesting... `printk_pending' is used in console_unlock(), which is
always available.

	-ss

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#1650454

On Thu 2017-05-25 21:36:33, Sergey Senozhatsky wrote:
> On (05/25/17 14:11), Petr Mladek wrote:
> [..]
> > The variable is used only when CONFIG_PRINTK is defined at
> > the moment, so this produces a warning about an unused variable.
> > 
> 
> interesting... `printk_pending' is used in console_unlock(), which is
> always available.

Yeah, I see. But this usage is introduced in the 2nd patch. I started
the review sequentially ;-)

Best Regards,
Petr

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