Re: [PATCH v1 05/31] x86/resctrl: Remove rdtgroup from update_cpu_closid_rmid()

Reinette Chatre
2024-04-18T05:12:42Z

Hi Dave,

On 4/16/2024 9:16 AM, Dave Martin wrote:
> On Mon, Apr 15, 2024 at 10:47:55AM -0700, Reinette Chatre wrote:
>> On 4/12/2024 9:12 AM, Dave Martin wrote:
>>> On Mon, Apr 08, 2024 at 08:16:08PM -0700, Reinette Chatre wrote:
>>>> On 3/21/2024 9:50 AM, James Morse wrote:
...

>> Do you imply that this would maintain the order in this patch? It does
>> not look to me that it would but I may be looking wrong.
>
> I'm not sure without looking again, but since this discussion is not a
> good use of your time I'll just go ahead and implement the change at
> [*] above, while restoring referse FIR order, if that is good for you.
>
>>
>> sidenote: the "on_each_cpu_mask()" in update_closid_rmid() can be on
>> one line.
>
> I guess that might have been split to stick to the 80-char limit.
>
> Due the the small size of this function, shall I just rename defaults_p to p?
> Alternatively, there are already a few non-printk lines over 80 chars, so
> maybe we can tolerate one more here?

80 chars are not enforced so strictly that it impacts readability. You
may refer to how update_task_closid_rmid() looks for more confidence in/
motivation for placing this on one line.

>
>>
>> ..
>>
>>>>> + * struct resctrl_cpu_sync, or NULL.
>>>>> + */
>>>>
>>>> Updating the CPU's defaults is not the primary goal of this function and because
>>>> of that I do not think this should be the focus with the main goal (updating
>>>> RMID and CLOSID on CPU) ignored. Specifically, this function only updates
>>>> the defaults if *info is set but it _always_ ensures CPU is running with
>>>> appropriate CLOSID/RMID (which may or may not be from a CPU default).
>>>>
>>>> I think resctrl_arch_sync_cpu_closid_rmid() may be more appropriate
>>>> and the comment needs to elaborate what the function does.
>>>>
>>>>> +void resctrl_arch_sync_cpu_defaults(void *info);
>>>
>>> That seems reasonable, and follows the original naming and what the
>>> code does:
>>>
>>> What about:
>>>
>>> /**
>>> * resctrl_arch_sync_cpu_defaults() - Refresh the CPU's CLOSID and RMID.
>>> * Call via IPI.
>>
>> Did you intend to change function name?
>
> Er, yes, I meant to use your suggestion here, so:
> resctrl_arch_sync_cpu_closid_rmid().
>

I'm a bit confused here when comparing with your response in [1] mentioning
a change to another name.

[1] https://lore.kernel.org/lkml/Zh6kgs1%2fbji1P1Hl@e133380.arm.com/

> Also, Babu Moger's suggestion to rename struct resctrl_cpu_sync
> to resctrl_cpu_defaults seems good, since that accurately describes what
> is specified in the struct (and what is *not* specified if NULL is
> passed).

Sounds good, yes.

Reinette