Re: [PATCH v11 2/8] x86/resctrl: Prepare for per-CTRL_MON group mba_MBps control

Reinette Chatre
2024-12-09T23:40:17Z

Hi Tony,

On 12/9/24 2:35 PM, Luck, Tony wrote:
>>> mba_mbps_default_event isn't architecture specific. The mba_MBps
>>> feedback code could be implemented on any architecture that supports
>>> both measurement and control of memory bandwidth.
>>
>> Yes, and it should be moved to that header then, right?
>>
>> But not earlier.
>
> If you feel strongly about it then go ahead and cut the line from <linux/rectrl.h>
> and paste it into <asm/resctrl.h>

I am not sure about this ... I expect the code needing this initially will
form part of the filesystem code so it may be more intuitive to have it
be located in arch/x86/kernel/cpu/resctrl/internal.h as Boris suggested.
As part of the arch/fs split it may then move to fs/resctrl/internal.h

mba_mbps_default_event may even stay internal to the fs/resctrl code with an
arch helper created later to initialize it. This is because I think
the initialization of mba_mbps_default_event may move out of
get_rdt_mon_resources() into resctrl_mon_resource_init() that is being
created as part of the MPAM work [1]. An example of current fs initialization
done in arch code that is moved to it can be found in [2].

Reinette

[1] https://lore.kernel.org/all/20241004180347.19985-17-james.morse@arm.com/
[2] https://lore.kernel.org/all/20241004180347.19985-20-james.morse@arm.com/