Re: [PATCH 2/7] x86/resctrl: Add SDCIAE feature in the command line options

Moger, Babu
2024-09-18T14:38:19Z

Hi Reinette,

On 9/13/24 15:45, Reinette Chatre wrote:
> Hi Babu,
>
> On 8/16/24 9:16 AM, Babu Moger wrote:
>> Add the command line options to enable or disable the new resctrl feature
>> L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE).
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>>   Documentation/admin-guide/kernel-parameters.txt | 2 +-
>>   arch/x86/kernel/cpu/resctrl/core.c              | 2 ++
>>   2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt
>> b/Documentation/admin-guide/kernel-parameters.txt
>> index 09126bb8cc9f..63f17d23b8f4 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -5604,7 +5604,7 @@
>>       rdt=        [HW,X86,RDT]
>>               Turn on/off individual RDT features. List is:
>>               cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,
>> -            mba, smba, bmec.
>> +            mba, smba, bmec, sdciae.
>>               E.g. to turn on cmt and turn off mba use:
>>                   rdt=cmt,!mba
>>   diff --git a/arch/x86/kernel/cpu/resctrl/core.c
>> b/arch/x86/kernel/cpu/resctrl/core.c
>> index 1930fce9dfe9..c4dfc768ddf5 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -801,6 +801,7 @@ enum {
>>       RDT_FLAG_MBA,
>>       RDT_FLAG_SMBA,
>>       RDT_FLAG_BMEC,
>> +    RDT_FLAG_SDCIAE,
>>   };
>>     #define RDT_OPT(idx, n, f)    \
>> @@ -826,6 +827,7 @@ static struct rdt_options rdt_options[]  __initdata = {
>>       RDT_OPT(RDT_FLAG_MBA,        "mba",    X86_FEATURE_MBA),
>>       RDT_OPT(RDT_FLAG_SMBA,        "smba",    X86_FEATURE_SMBA),
>>       RDT_OPT(RDT_FLAG_BMEC,        "bmec",    X86_FEATURE_BMEC),
>> +    RDT_OPT(RDT_FLAG_SDCIAE,    "sdciae",    X86_FEATURE_SDCIAE),
>>   };
>>   #define NUM_RDT_OPTIONS ARRAY_SIZE(rdt_options)
>>
>
> Why is this needed when patch #5 introduces an interface to enable/disable
> this feature after mount?

We have provided option to disable the RDT features on boot. To be
consistent, I have add this feature also to the list.

Yes. Feature can be enabled or disabled after mount.
Thanks
Babu Moger