Re: [PATCH v2 1/2] init/Kconfig: Fix CPU number in LOG_CPU_MAX_BUF_SHIFT description

2020-11-02 Thread Petr Mladek 
On Fri 2020-10-30 17:00:18, Paul Menzel wrote:
> Dear Petr,
> 
> 
> Am 11.08.20 um 11:29 schrieb Paul Menzel:
> > Currently, LOG_BUF_SHIFT defaults to 17, which is 2 ^ 17 bytes = 128 KB,
> > and LOG_CPU_MAX_BUF_SHIFT defaults to 12, which is 2 ^ 12 bytes = 4 KB.
> > 
> > Half of 128 KB is 64 KB, so more than 16 CPUs are required for the value
> > to be used, as then the sum of contributions is greater than 64 KB for
> > the first time. My guess is, that the description was written with the
> > configuration values used in the SUSE in mind.
> > 
> > Fixes: 23b2899f7f ("printk: allow increasing the ring buffer depending on 
> > the number of CPUs")
> > Cc: Luis R. Rodriguez 
> > Cc: linux-kernel@vger.kernel.org
> > Reviewed-by: Petr Mladek 
> > Signed-off-by: Paul Menzel 
> > ---
> > v2: Add Reviewed-by tag
> > 
> >   init/Kconfig | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/init/Kconfig b/init/Kconfig
> > index d6a0b31b13dc..9dc607e3806f 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -718,7 +718,7 @@ config LOG_CPU_MAX_BUF_SHIFT
> >   with more CPUs. Therefore this value is used only when the sum of
> >   contributions is greater than the half of the default kernel ring
> >   buffer as defined by LOG_BUF_SHIFT. The default values are set
> > - so that more than 64 CPUs are needed to trigger the allocation.
> > + so that more than 16 CPUs are needed to trigger the allocation.
> >   Also this option is ignored when "log_buf_len" kernel parameter is
> >   used as it forces an exact (power of two) size of the ring buffer.
> 
> Could you please apply this trivial patch from the two patches already, so I
> do not have to resend it?

The patch is committed in printk/linux.git, branch for-5.10-trivial.

I am not going to create pull request just for this trivial fix.
I will push it for-5.10 only together with eventual more urgent fix.
It is very likely that it will have to wait for 5.11.

Best Regards,
Petr

Re: [PATCH v2 1/2] init/Kconfig: Fix CPU number in LOG_CPU_MAX_BUF_SHIFT description

2020-10-30 Thread Paul Menzel 

Dear Petr,


Am 11.08.20 um 11:29 schrieb Paul Menzel:

Currently, LOG_BUF_SHIFT defaults to 17, which is 2 ^ 17 bytes = 128 KB,
and LOG_CPU_MAX_BUF_SHIFT defaults to 12, which is 2 ^ 12 bytes = 4 KB.

Half of 128 KB is 64 KB, so more than 16 CPUs are required for the value
to be used, as then the sum of contributions is greater than 64 KB for
the first time. My guess is, that the description was written with the
configuration values used in the SUSE in mind.

Fixes: 23b2899f7f ("printk: allow increasing the ring buffer depending on the number 
of CPUs")
Cc: Luis R. Rodriguez 
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Petr Mladek 
Signed-off-by: Paul Menzel 
---
v2: Add Reviewed-by tag

  init/Kconfig | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index d6a0b31b13dc..9dc607e3806f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -718,7 +718,7 @@ config LOG_CPU_MAX_BUF_SHIFT
  with more CPUs. Therefore this value is used only when the sum of
  contributions is greater than the half of the default kernel ring
  buffer as defined by LOG_BUF_SHIFT. The default values are set
- so that more than 64 CPUs are needed to trigger the allocation.
+ so that more than 16 CPUs are needed to trigger the allocation.
  
  	  Also this option is ignored when "log_buf_len" kernel parameter is

  used as it forces an exact (power of two) size of the ring buffer.


Could you please apply this trivial patch from the two patches already, 
so I do not have to resend it?



Kind regards,

Paul

[PATCH v2 1/2] init/Kconfig: Fix CPU number in LOG_CPU_MAX_BUF_SHIFT description

2020-08-11 Thread Paul Menzel 
Currently, LOG_BUF_SHIFT defaults to 17, which is 2 ^ 17 bytes = 128 KB,
and LOG_CPU_MAX_BUF_SHIFT defaults to 12, which is 2 ^ 12 bytes = 4 KB.

Half of 128 KB is 64 KB, so more than 16 CPUs are required for the value
to be used, as then the sum of contributions is greater than 64 KB for
the first time. My guess is, that the description was written with the
configuration values used in the SUSE in mind.

Fixes: 23b2899f7f ("printk: allow increasing the ring buffer depending on the 
number of CPUs")
Cc: Luis R. Rodriguez 
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Petr Mladek 
Signed-off-by: Paul Menzel 
---
v2: Add Reviewed-by tag

 init/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index d6a0b31b13dc..9dc607e3806f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -718,7 +718,7 @@ config LOG_CPU_MAX_BUF_SHIFT
  with more CPUs. Therefore this value is used only when the sum of
  contributions is greater than the half of the default kernel ring
  buffer as defined by LOG_BUF_SHIFT. The default values are set
- so that more than 64 CPUs are needed to trigger the allocation.
+ so that more than 16 CPUs are needed to trigger the allocation.
 
  Also this option is ignored when "log_buf_len" kernel parameter is
  used as it forces an exact (power of two) size of the ring buffer.
-- 
2.28.0