Re: [PATCH v2 2/2] init/Kconfig: Increase default log buffer size from 128 KB to 512 KB

[Paul Menzel]

Dear Petr,


Am 11.08.20 um 12:53 schrieb Petr Mladek:
> On Tue 2020-08-11 11:29:24, Paul Menzel wrote:
> > Commit f17a32e97e (let LOG_BUF_SHIFT default to 17) from 2008 was the
> > last time, the the default log buffer size bump was increased.
> >
> > Machines have evolved, and on current hardware, enough memory is
> > present, and some devices have over 200 PCI devices, like a two socket
> > Skylake-E server, resulting a lot of lines.
> >
> > Therefore, increase the default from 128 KB to 512 KB. Anyone, with
> > limited memory, can still lower it.
> >
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -681,9 +681,9 @@ config IKHEADERS
> >   	  kheaders.ko is built which can be loaded on-demand to get access to headers.
> >   
> >   config LOG_BUF_SHIFT
> > -	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
> > +	int "Kernel log buffer size (17 => 128KB, 19 => 512KB)"
> >   	range 12 25
> > -	default 17
> > +	default 19
> >   	depends on PRINTK
> >   	help
> >   	  Select the minimal kernel log buffer size as a power of 2.
>
> Honestly, I do not have experience with changing the defaults. People
> hacking small devices might complain. Well, this can be solved
> by increasing the default only when BASE_FULL is set.
>
> I am personally fine with increasing the default when BASE_FULL
> is set. The amount of messages is growing over time because of
> increasing complexity of both the hardware and software.
> Fortunately also the amount of available memory is growing.
>
> Well, this should get discussed in wider audience. Adding some
> people into CC.
>
> JFYI, it started with report of lost messages, see
> https://lore.kernel.org/lkml/264bfbae-122d-9c41-59ea-6413f91bd866@xxxxxxxxxxxxx/

As there was no objection, is it possible to apply the two patches, and 
maybe even get them into Linux 5.10?


Kind regards,

Paul