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To:     Petr Mladek <pmladek@suse.com>,
        Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH printk 3/5] printk: use buffer pool for sprint buffers
In-Reply-To: <20200930085131.GY29288@alley>
References: <20200922153816.5883-1-john.ogness@linutronix.de> <20200922153816.5883-4-john.ogness@linutronix.de> <20200923151129.GC6442@alley> <aef3626f-56a0-9040-fc0e-224ada032d02@prevas.dk> <2c95c16b-03e7-eadd-d3af-bedc6b0b471e@prevas.dk> <20200925082822.GL29288@alley> <4e36f308-a435-f9c1-2d4f-362e797c764e@prevas.dk> <20200930085131.GY29288@alley>
Date:   Wed, 30 Sep 2020 11:03:13 +0206
Message-ID: <87o8ln1w2e.fsf@jogness.linutronix.de>
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On 2020-09-30, Petr Mladek <pmladek@suse.com> wrote:
>> Doubling the cost of every single printk by unconditionally doing
>> vsnprintf() twice is a bad idea.
>
> I would prefer to solve this when there are real life problems.
> printk() should not get called in performance sensitive paths in
> the first place.
>
> We could always make the code more complicated when it can be
> justified. Extra buffers is yet another layer (code and memory)
> in the processing. And the current arguments sounds theoretical.

I am preparing a v2 that avoids the memory pool.

John Ogness