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Groups > linux.kernel > #1289990
| From | Andrew Morton <akpm@linux-foundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable |
| Date | 2015-12-12 00:00 +0100 |
| Message-ID | <qEEPp-2db-29@gated-at.bofh.it> (permalink) |
| References | <qDMYG-u3-13@gated-at.bofh.it> <qDMYG-u3-11@gated-at.bofh.it> <qEtTY-3va-19@gated-at.bofh.it> <qEvj4-4o4-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, 11 Dec 2015 13:41:59 +0100 Petr Mladek <pmladek@suse.com> wrote:
> On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote:
> > On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek <pmladek@suse.com> wrote:
> > > --- a/init/Kconfig
> > > +++ b/init/Kconfig
> > > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT
> > > 13 => 8 KB for each CPU
> > > 12 => 4 KB for each CPU
> > >
> > > +config NMI_LOG_BUF_SHIFT
> > > + int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)"
> > > + range 10 21
> > > + default 13
> > > + depends on PRINTK && HAVE_NMI
> >
> > Symbol NMI_LOG_BUF_SHIFT does not exist if its dependencies are not met.
>
> __h, the NMI buffer is enabled on arm via NEED_PRINTK_NMI.
>
> The buffer is compiled when CONFIG_PRINTK_NMI is defined. I am going
> to fix it the following way:
>
>
> diff --git a/init/Kconfig b/init/Kconfig
> index efcff25a112d..61cfd96a3c96 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -870,7 +870,7 @@ config NMI_LOG_BUF_SHIFT
> int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)"
> range 10 21
> default 13
> - depends on PRINTK && HAVE_NMI
> + depends on PRINTK_NMI
> help
> Select the size of a per-CPU buffer where NMI messages are temporary
> stored. They are copied to the main log buffer in a safe context
I'm wondering why we're building kernel/printk/nmi.o if HAVE_NMI is not
set.
obj-$(CONFIG_PRINTK_NMI) += nmi.o
and
config PRINTK_NMI
def_bool y
depends on PRINTK
depends on HAVE_NMI || NEED_PRINTK_NMI
This is a bit messy. NEED_PRINTK_NMI is an added-on hack for one
particular arm variant. From the changelog:
"One exception is arm where the deferred printing is used for
printing backtraces even without NMI. For this purpose, we define
NEED_PRINTK_NMI Kconfig flag. The alternative printk_func is
explicitly set when IPI_CPU_BACKTRACE is handled."
- why does arm needs deferred printing for backtraces?
- why is this specific to CONFIG_CPU_V7M?
- can this Kconfig logic be cleaned up a bit?
--
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[PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Petr Mladek <pmladek@suse.com> - 2015-12-09 14:30 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Geert Uytterhoeven <geert@linux-m68k.org> - 2015-12-11 12:20 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Arnd Bergmann <arnd@arndb.de> - 2015-12-11 13:50 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Petr Mladek <pmladek@suse.com> - 2015-12-11 13:50 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Geert Uytterhoeven <geert@linux-m68k.org> - 2015-12-11 14:00 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Andrew Morton <akpm@linux-foundation.org> - 2015-12-12 00:00 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Jiri Kosina <jikos@kernel.org> - 2015-12-12 00:30 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Daniel Thompson <daniel.thompson@linaro.org> - 2015-12-18 11:20 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Peter Zijlstra <peterz@infradead.org> - 2015-12-18 12:30 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Peter Zijlstra <peterz@infradead.org> - 2015-12-18 13:20 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Andrew Morton <akpm@linux-foundation.org> - 2015-12-19 00:10 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Petr Mladek <pmladek@suse.com> - 2015-12-18 16:00 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Daniel Thompson <daniel.thompson@linaro.org> - 2015-12-18 18:10 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-12-12 00:30 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Andrew Morton <akpm@linux-foundation.org> - 2015-12-12 00:40 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Petr Mladek <pmladek@suse.com> - 2015-12-15 15:30 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Andrew Morton <akpm@linux-foundation.org> - 2015-12-17 23:40 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Petr Mladek <pmladek@suse.com> - 2015-12-18 17:20 +0100
Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable Daniel Thompson <daniel.thompson@linaro.org> - 2015-12-14 11:30 +0100
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