[PATCH] lmb: Bump CONFIG_LMB_MAX_REGIONS

[Patrick DELAUNAY]

Hi,

On 2/17/23 10:28, Michal Suchánek wrote:
> Hello,
>
> On Sun, Feb 12, 2023 at 06:45:36PM -0500, Tom Rini wrote:
>> On Wed, Feb 08, 2023 at 02:50:16PM -0500, Tom Rini wrote:
>>> On Wed, Feb 08, 2023 at 08:11:34PM +0100, Michal Suchánek wrote:
>>>> Hello,
>>>>
>>>> On Wed, Feb 08, 2023 at 01:25:50PM -0500, Tom Rini wrote:
>>>>> On Wed, Feb 08, 2023 at 07:24:25PM +0100, Francesco Dolcini wrote:
>>>>>> Hello,
>>>>>>
>>>>>> On Fri, Jan 27, 2023 at 08:54:55AM -0500, Tom Rini wrote:
>>>>>>> On Fri, Jan 27, 2023 at 02:00:12PM +0100, Michal Suchanek wrote:
>>>>>>>> It is reported that in some configurations it is not possible to boot
>>>>>>>> because u-boot runs out of lmbs.
>>>>>>>>
>>>>>>>> commit 06d514d77c ("lmb: consider EFI memory map") increases lmb usage,
>>>>>>>> hence is likely the cause of the lmb overflow.
>>>>>>>>
>>>>>>>> Fixes: 06d514d77c ("lmb: consider EFI memory map")
>>>>>>>> Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1207562
>>>>>>>> Signed-off-by: Michal Suchanek <msuchanek at suse.de>
>>>>>> Reviewed-by: Francesco Dolcini <francesco.dolcini at toradex.com>
>>>>>>
>>>>>>> I plan to pick up
>>>>>>> https://patchwork.ozlabs.org/project/uboot/patch/20230125230823.1567778-1-trini@konsulko.com/
>>>>>>> as the alternative fix for this issue and would suggest that any distro
>>>>>>> hitting the problem on v2023.01 apply the above instead of increasing
>>>>>>> the limit.
>>>>>> Tom, my understanding is that you plan to merge this or an equivalent
>>>>>> change, correct? Otherwise I would need to send some more patches to
>>>>>> update a few board defconfig that are affected by this specific issue.
>>>>> Yes, I was hoping to push the equivalent of this patch a few hours ago,
>>>>> along with the revert. Then I noticed the test in test/lib/lmb.c doesn't
>>>>> scale past 8, and I just now figured out what that should look like
>>>>> instead, I believe.
>>>> reportedly neither fixes the problem in all cases, and raising
>>>> CONFIG_LMB_RESERVED_REGIONS is required.
>>>>
>>>> Looks like the mechanism to add regions above the default number does
>>>> not work as intended.
>>>>
>>>> The test is to boot rPi 4 from USB directly with recent firmware.
>>> Well, given 0089affee275 ("configs: stm32mp15: increase the number of
>>> reserved memory region in lmb") I guess this has been run in to before,
>>> but not resolved more generically.
>> I wonder if
>> https://patchwork.ozlabs.org/project/uboot/patch/20230212150706.2967007-2-sjoerd@collabora.com/
>> is what will finish dealing with these issues, even the ones that had
>> perhaps shown up before and been addressed in the commit I mentioned
>> above?
> Looks like this together with raising the maximum number of regions
> works, that is v2023.04-rc2 should be fixed.
>
> Thanks
>
> Michal


For STM32MP15x platform with have the same issue when the number of 
reserved regions increased in Linux device tree.


I try to increase the region by default with CONFIG_LMB_MAX_REGIONS,

but my patch increase the used RAM size for some platform (with 
compilation issue).


For Tom ask me to propose a backward compatible configuration

https://lore.kernel.org/all/18550712-c32d-e08b-c38e-6c63bad09009@foss.st.com/

=> CONFIG_USE_LMB_MAX_REGIONS


Moreover, if you increased CONFIG_LMB_MAX_REGIONS

the same number of region (N) is used for reserved regions (N) and for  
memory region (N)

=> the total size used = 2 * N * size of each memory region descriptor.


But for most of case only the number reserved regions need to be 
increased to parse the device tree.


With my patch the number of regions are statically managed by  2 array 
independently

- reserved regions = CONFIG_LMB_RESERVED_REGIONS

- memory region = CONFIG_LMB_MEMORY_REGIONS

And the total number of region (size of struct in memory) =

CONFIG_LMB_RESERVED_REGIONS + CONFIG_LMB_MEMORY_REGIONS


I think a good solution to have by default, if you want managed more 
reserved memory by default in U-Boot for all platform:


=> LMB_USE_MAX_REGIONS=n  instead of 'y' today

=> LMB_MEMORY_REGIONS=8

=> LMB_RESERVED_REGIONS=16 or 32 instead of 8 today by default


And change the defconfig for the size constraint platforms

to use the previous behavior with LMB_USE_MAX_REGIONS=y.


NB: I define the default value with 8 to keep the previous limit and

        I just increase the number of region for the STM32MP platform:


configs/stm32mp15_defconfig:170:CONFIG_LMB_RESERVED_REGIONS=16
configs/stm32mp15_trusted_defconfig:170:CONFIG_LMB_RESERVED_REGIONS=16
configs/stm32mp13_defconfig:81:CONFIG_LMB_RESERVED_REGIONS=16
configs/stm32mp15_basic_defconfig:194:CONFIG_LMB_RESERVED_REGIONS=16

I use the default value for CONFIG_LMB_MEMORY_REGIONS =8


Reference = 
https://lore.kernel.org/all/20210310091632.17103-1-patrick.delaunay@foss.st.com/


Patrick