linux-kernel - Re: [PATCH v2] printk: Remove redundant CONFIG_BASE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <871q9xzeqz.fsf@jogness.linutronix.de>
Date: Wed, 31 Jan 2024 16:53:32 +0106
From: John Ogness <john.ogness@...utronix.de>
To: Luis Chamberlain <mcgrof@...nel.org>, Yoann Congal
 <yoann.congal@...le.fr>, Josh Triplett <josh@...htriplett.org>, Petr
 Mladek <pmladek@...e.com>, Steven Rostedt <rostedt@...dmis.org>, Sergey
 Senozhatsky <senozhatsky@...omium.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
 linux-serial@...r.kernel.org, linux-fsdevel@...r.kernel.org,
 linux-kbuild@...r.kernel.org, Geert Uytterhoeven <geert@...ux-m68k.org>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 "H. Peter Anvin" <hpa@...or.com>, Greg Kroah-Hartman
 <gregkh@...uxfoundation.org>, Jiri Slaby <jirislaby@...nel.org>, Willem de
 Bruijn <willemdebruijn.kernel@...il.com>, Matthew Wilcox
 <willy@...radead.org>, Peter Zijlstra <peterz@...radead.org>, Darren Hart
 <dvhart@...radead.org>, Davidlohr Bueso <dave@...olabs.net>, André Almeida
 <andrealmeid@...lia.com>, Masahiro Yamada <masahiroy@...nel.org>
Subject: Re: [PATCH v2] printk: Remove redundant CONFIG_BASE_SMALL

On 2024-01-29, Luis Chamberlain <mcgrof@...nel.org> wrote:
> You should mention the one case which this patch fixes is:
>
>> CONFIG_BASE_SMALL was used that way in init/Kconfig:
>>   config LOG_CPU_MAX_BUF_SHIFT
>>   	default 12 if !BASE_SMALL
>>   	default 0 if BASE_SMALL
>
> You should then mention this has been using 12 for a long time now
> for BASE_SMALL, and so this patch is a functional fix for those
> who used BASE_SMALL and wanted a smaller printk buffer contribtion per
> cpu. The contribution was only per CPU, and since BASE_SMALL systems
> likely don't have many CPUs the impact of this was relatively small,
> 4 KiB per CPU.  This patch fixes that back down to 0 KiB per CPU.

For printk this will mean that BASE_SMALL systems were probably
previously allocating/using the dynamic ringbuffer and now they will
just continue to use the static ringbuffer. Which is fine and saves
memory (as it should).

Reviewed-by: John Ogness <john.ogness@...utronix.de>