Re: [PATCH 2/5] x86,fs/resctrl: Remove "arch_needs_linear"

[Reinette Chatre]

Hi Chenyu,

On 9/3/26 8:14 PM, Chen Yu wrote:
> Hi Reinette,
> 
> On Thu, Sep 03, 2026 at 09:57:04AM -0700, Reinette Chatre wrote:
> 
> [ ... ]
> 
>>  static __init bool __get_mem_config_intel(struct rdt_resource *r)
>>  {
>>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>> @@ -213,16 +192,13 @@ static __init bool __get_mem_config_intel(struct rdt_resource *r)
>>  	hw_res->num_closid = edx.split.cos_max + 1;
>>  	max_delay = eax.split.max_delay + 1;
>>  	r->membw.max_bw = MAX_MBA_BW;
>> -	r->membw.arch_needs_linear = true;
>> -	if (ecx & MBA_IS_LINEAR) {
>> -		r->membw.delay_linear = true;
>> -		r->membw.min_bw = MAX_MBA_BW - max_delay;
>> -		r->membw.bw_gran = MAX_MBA_BW - max_delay;
>> -	} else {
>> -		if (!rdt_get_mb_table(r))
>> -			return false;
>> -		r->membw.arch_needs_linear = false;
>> -	}
>> +
>> +	if (!(ecx & MBA_IS_LINEAR))
> 
> Maybe also print the following from rdt_get_mb_table()?
> 	pr_info("MBA b/w map not implemented for cpu:%d, model:%d",
> 		boot_cpu_data.x86, boot_cpu_data.x86_model);
> 
> In the previous patch, a "Non Linear delay-bw map" warning is triggered
> during the actual write operation. Similarly, displaying such a message
> during bootup in this patch might also be helpful.
ok ... but who will the message be helpful to? This is a check of
hardware state, not x86 resctrl driver state as in the previous patch.

Reinette