Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <16aacc2a1ac272da356b778217406288abb7377e.camel@perches.com>
Subject: Re: [PATCH] printk: Add loglevel for "do not print to consoles".
From:   Joe Perches <joe@perches.com>
To:     Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-kernel@vger.kernel.org, Dmitry Safonov <dima@arista.com>,
        Michal Hocko <mhocko@suse.com>,
        Yafang Shao <laoar.shao@gmail.com>
Date:   Wed, 06 May 2020 22:30:17 -0700
In-Reply-To: <36db0dfe-9d7e-0616-cbe6-4bfb99a1f470@i-love.sakura.ne.jp>
References: <20200424024239.63607-1-penguin-kernel@I-love.SAKURA.ne.jp>
         <20200425004609.GE8982@jagdpanzerIV.localdomain>
         <842ff40b-a232-6098-4333-996a3033b30a@i-love.sakura.ne.jp>
         <20200427062117.GC486@jagdpanzerIV.localdomain>
         <4dae86af-1d9a-f5a8-cff6-aa91ec038a79@i-love.sakura.ne.jp>
         <344199f1-639b-ee93-2388-57b0549641f9@i-love.sakura.ne.jp>
         <dfe10cb0359c37dff46c93dfacf909dd33b2593f.camel@perches.com>
         <0d513c80-8c8e-17b6-5b9c-73c7bca77252@i-love.sakura.ne.jp>
         <63f58a1c334d8d44ddf1788091be9b2232054b03.camel@perches.com>
         <36db0dfe-9d7e-0616-cbe6-4bfb99a1f470@i-love.sakura.ne.jp>
Content-Type: text/plain; charset="ISO-8859-1"
User-Agent: Evolution 3.36.1-2 
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, 2020-05-07 at 14:13 +0900, Tetsuo Handa wrote:
> On 2020/05/07 10:02, Joe Perches wrote:
> > > > printk_get_level / printk_skip_level and the various
> > > > uses of %pV using printk_get_level
> > > > 
> > > 
> > > Excuse me, but what do you mean?
> > > 
> > > I wish printk() accepts "loglevel" argument detached from "fmt" argument (e.g.
> > 
> > I think that's a bad idea as it would expand
> > _every_ use of printk with another argument
> > and overall code size would increase for very
> > little value.
> 
> I'm not saying that we should add loglevel argument to all printk() callers.
> I'm saying that we could add a variant of printk() which accepts loglevel
> argument (say, e.g. printkl() and vprintkl()).
> 
> I think that some of printk_get_level() users are using printk_get_level() only
> for detaching loglevel argument from fmt argument.

I believe wrote all of those.

> I don't know how the lockless logbuf will replace printk_safe_flush_buffer(). But I guess
> it is possible to avoid printk_safe_flush_buffer() and printk_skip_level() as demonstrated
> by https://lkml.kernel.org/r/5e192ca2-3b24-0b45-fc13-51feec43c216@i-love.sakura.ne.jp .
> 
> Then, printk_skip_headers() will be the only user of printk_skip_level(). I don't know how
> vkdb_printf() works, but vkdb_printf() is currently using printk_skip_level() in order to
> remove loglevel argument. We can avoid printk_skip_level() if loglevel argument is detached
>  from fmt argument.

a vprintk_emit variant would probably do.

I proposed awhile back making functions for pr_<level>
https://lore.kernel.org/lkml/1466739971-30399-1-git-send-email-joe@perches.com/

Maybe it's time for that and something appropriate
like it for your next use too.