Re: [PATCH v2] printk: make sure to print log on console.

From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Maninder Singh <maninder1.s@samsung.com>,
	sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
	linux-kernel@vger.kernel.org, a.sahrawat@samsung.com,
	pankaj.m@samsung.com, v.narang@samsung.com
Subject: Re: [PATCH v2] printk: make sure to print log on console.
Date: Tue, 19 Jun 2018 18:49:53 +0900	[thread overview]
Message-ID: <20180619094953.GB2631@jagdpanzerIV> (raw)
In-Reply-To: <20180619093244.ehj34uhpnpv6447f@pathway.suse.cz>

On (06/19/18 11:32), Petr Mladek wrote:
> > -               if (suppress_message_printing(msg->level)) {
> > +               if (!ignore_loglevel && (msg->flags & LOG_NOCONS)) {
> > 
> > 
> > `ignore_loglevel' is a module param and can change any time via
> > 	/sys/module/printk/parameters/ignore_loglevel
> > we need to respect its value.
> 
> I would prefer to keep the patch as is. I see it the following way.
> 
> Also console_loglevel can be changed anytime by /proc/sys/kernel/printk.
> The patch basically moves the decision about the message visibility from
> console_unlock() to vprintk_emit(). The logic is easier when all
> aspects are handled in a single location and only once.

But when I set /sys/module/printk/parameters/ignore_loglevel I naturally
expect it to take an immediate action. Without waiting for the consoles
to catch up and to discard N messages [if the consoles were behind the
logbuf head].

	-ss