Re: [v2 1/1] x86/cpufeatures: Implement Predictive Store Forwarding control.

From: Randy Dunlap
Date: Thu Apr 22 2021 - 16:47:34 EST


On 4/22/21 12:32 PM, Saripalli, RK wrote:
>
>
> On 4/22/2021 12:49 PM, Randy Dunlap wrote:
>> On 4/22/21 10:10 AM, Ramakrishna Saripalli wrote:
>>> From: Ramakrishna Saripalli <rk.saripalli@xxxxxxx>
>>>
>>> ====================
>>> Signed-off-by: Ramakrishna Saripalli<rk.saripalli@xxxxxxx>
>>> ---
>>> .../admin-guide/kernel-parameters.txt | 5 +++++
>>> arch/x86/include/asm/cpufeatures.h | 1 +
>>> arch/x86/include/asm/msr-index.h | 2 ++
>>> arch/x86/kernel/cpu/amd.c | 19 +++++++++++++++++++
>>> 4 files changed, 27 insertions(+)
>>
>> as from v1:
>
> Randy, could you clarify your comments please?. Is there something here I need to change/clarify/fix?
>

Only that I had made these same comments (below)
in v1 of the patch.

https://lore.kernel.org/lkml/4c688fc7-67df-3187-54b2-bf20e510fb39@xxxxxxxxxxxxx/

>>
>>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>>> index 04545725f187..58f6bd02385b 100644
>>> --- a/Documentation/admin-guide/kernel-parameters.txt
>>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>>> @@ -3940,6 +3940,11 @@
>>> Format: {"off"}
>>> Disable Hardware Transactional Memory
>>>
>>> + predict_store_fwd [X86] This option controls PSF mitigation
>>
>> predict_store_fwd= ...
>>
>
> OK
>
>>> + off - Turns on PSF mitigation.
>>> + on - Turns off PSF mitigation.
>>> + default : on.
>>
>> default: on.
>>
>
> OK
>
>>> +
>>> preempt= [KNL]
>>> Select preemption mode if you have CONFIG_PREEMPT_DYNAMIC
>>> none - Limited to cond_resched() calls

--
~Randy