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SubjectRe: [RFC PATCH V2 11/22] x86/intel_rdt: Associate pseudo-locked regions with its domain
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Hi Thomas,

On 2/19/2018 1:19 PM, Thomas Gleixner wrote:
> On Tue, 13 Feb 2018, Reinette Chatre wrote:
>
>> After a pseudo-locked region is locked it needs to be associated with
>> the RDT domain representing the pseudo-locked cache so that its life
>> cycle can be managed correctly.
>>
>> Only a single pseudo-locked region can exist on any cache instance so we
>> maintain a single pointer to a pseudo-locked region from each RDT
>> domain.
>
> Why is only a single pseudo locked region possible?

The setup of a pseudo-locked region requires the usage of wbinvd. If a
second pseudo-locked region is thus attempted it will evict the
pseudo-locked data of the first.

>
>> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
>> ---
>> arch/x86/kernel/cpu/intel_rdt.h | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
>> index 060a0976ac00..f0e020686e99 100644
>> --- a/arch/x86/kernel/cpu/intel_rdt.h
>> +++ b/arch/x86/kernel/cpu/intel_rdt.h
>> @@ -187,6 +187,8 @@ struct mbm_state {
>> u64 prev_msr;
>> };
>>
>> +struct pseudo_lock_region;
>> +
>> /**
>> * struct rdt_domain - group of cpus sharing an RDT resource
>> * @list: all instances of this resource
>> @@ -205,6 +207,7 @@ struct mbm_state {
>> * @ctrl_val: array of cache or mem ctrl values (indexed by CLOSID)
>> * @new_ctrl: new ctrl value to be loaded
>> * @have_new_ctrl: did user provide new_ctrl for this domain
>> + * @plr: pseudo-locked region associated with this domain
>> */
>> struct rdt_domain {
>> struct list_head list;
>> @@ -220,6 +223,7 @@ struct rdt_domain {
>> u32 *ctrl_val;
>> u32 new_ctrl;
>> bool have_new_ctrl;
>> + struct pseudo_lock_region *plr;
>
> Please keep the tabular fashion of the struct declaration intact.

Will fix.

Reinette

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