[PATCH 4/5] log: convert pr_*() to logging

[Patrice CHOTARD <patrice.chotard@foss.st.com>]

Hi Tom

On 2/18/21 2:05 PM, Tom Rini wrote:
> On Thu, Feb 18, 2021 at 10:16:58AM +0100, Heinrich Schuchardt wrote:
>> On 18.01.21 16:30, Tom Rini wrote:
>>> On Mon, Jan 18, 2021 at 08:02:41AM -0500, Tom Rini wrote:
>>>> On Sun, Jan 17, 2021 at 08:37:15AM +0100, Heinrich Schuchardt wrote:
>>>>> On 1/17/21 1:16 AM, Tom Rini wrote:
>>>>>> On Mon, Jan 04, 2021 at 08:02:55AM +0100, Heinrich Schuchardt wrote:
>>>>>>
>>>>>>> In drivers we use a family of printing functions including pr_err() and
>>>>>>> pr_cont(). CONFIG_LOGLEVEL is used to control which of these lead to output
>>>>>>> via printf().
>>>>>>>
>>>>>>> Our logging functions allow finer grained control of output. So replace
>>>>>>> printf() by the matching logging functions. The usage of CONFIG_LOGLEVEL
>>>>>>> remains unchanged.
>>>>>>>
>>>>>>> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
>>>>>>> ---
>>>>>>>   include/linux/bitops.h |  4 ++-
>>>>>>>   include/linux/printk.h | 82 +++++++++++++++++++++++-------------------
>>>>>>>   2 files changed, 48 insertions(+), 38 deletions(-)
>>>>>>
>>>>>> This causes some fairly massive growth in various subsystems such as ubi
>>>>>> and we might want to look at what, if anything, we can do, before
>>>>>> growing some platforms by 15KiB (xilinx_zynqmp_virt) due to strings.
>>>>>
>>>>> xilinx_zynqmp_virt has CONFIG_LOG enabled. Switching from printf() to
>>>>> log() incurs size growth. Did you observe a size grows on platforms with
>>>>> CONFIG_LOG=n?
>>>>
>>>> Yes, it has logging enabled, and we're converting a large number of
>>>> things that were before compile-time discarded to no longer be so.  This
>>>> is, in general, good and what I've asked for.  But when seeing very
>>>> large growth in doing so, I think we need to maybe take a step back and
>>>> look at the UBI subsystem for example and see if we can't/shouldn't
>>>> tweak things more.
>>>>
>>>> So, I'm going to run a size test with just this patch as the change, so
>>>> we can have more concrete numbers to look at.
>>>
>>> OK, so the build is done and interesting output starts at:
>>> https://gist.github.com/trini/53e7da62c6c9d18c189e6baffd01ff00#file-2021-01-18-0800-txt-L239
>>>
>>> Most of the time we're well under 1KiB, which is great.  UBI has some
>>> huge growth, but it's a very few platforms, and I've added the
>>> custodians here so they can object, or not, to such size growth.
>>>
>>
>> Hello Tom,
>>
>> How shall we proceed?
> 
> Michal? Patrice or Patrick?  Since this patch causes noticeable growth
> on your platforms I'm waiting for your input here, to be clear.  Thanks!
> 

No objection for stm32 platforms, ok for us ;-)

Patrice