Re: [PATCH v12 12/25] arm,x86,fs/resctrl: Allocate maximum needed rmid_ptrs[]

[Babu Moger <babu.moger@amd.com>]

Hi Reinette,

On 9/21/26 19:30, Reinette Chatre wrote:
> Hi Babu,
> 
> Thank you for taking a look.
> 
> On 9/21/26 10:45 AM, Babu Moger wrote:
>> On 9/16/26 18:13, Tony Luck wrote:
> 
> ...
> 
>>> @@ -45,6 +45,9 @@ static DEFINE_MUTEX(domain_list_lock);
>>>     */
>>>    DEFINE_PER_CPU(struct resctrl_pqr_state, pqr_state);
>>>    +/* Number of RMIDS values that can be written to IA32_PQR_ASSOC.RMID */
>>> +static u32 pqr_assoc_num_rmid;
>>> +
>>>    static void mba_wrmsr_intel(struct msr_param *m);
>>>    static void cat_wrmsr(struct msr_param *m);
>>>    static void mba_wrmsr_amd(struct msr_param *m);
>>> @@ -124,6 +127,28 @@ u32 resctrl_arch_system_num_rmid_idx(void)
>>>        return num_rmids == U32_MAX ? 0 : num_rmids;
>>>    }
>>>    +/**
>>> + * resctrl_arch_system_max_rmid_idx - Largest possible number of RMIDs
>>> + *
>>> + * Return: Maximum possible number of RMIDs used for boot time allocations.
>>> + */
>>> +u32 resctrl_arch_system_max_rmid_idx(void)
>>> +{
>>> +    struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
>>> +    u32 num_rmid = pqr_assoc_num_rmid;
>>
>> Why not  use "cpuid_ebx(0xf) + 1" instead of global variable?
>>
> Tony did so in v11 but I proposed it to be changed [1]. This series adds
> multiple consumers of this value so it seems more efficient to enumerate
> it once and re-use that value when needed. Locating this one-time enumeration
> with all the other monitoring information enumerated from hardware in
> get_rdt_mon_resources() also has the benefit of keeping all monitoring data
> enumeration together.

Ok. Sounds good to me.

Thanks
Babu