Re: [RFC PATCH v4 0/6] arm64: tlb: add support for TTL feature

[Zhenyu Ye]

On 2020/3/25 21:32, Peter Zijlstra wrote:
> On Wed, Mar 25, 2020 at 12:49:45PM +0800, Zhenyu Ye wrote:
>> Hi Peter,
>>
>> On 2020/3/24 23:01, Peter Zijlstra wrote:
>>> On Tue, Mar 24, 2020 at 09:45:28PM +0800, Zhenyu Ye wrote:
>>>> In order to reduce the cost of TLB invalidation, the ARMv8.4 TTL
>>>> feature allows TLBs to be issued with a level allowing for quicker
>>>> invalidation.  This series provide support for this feature. 
>>>>
>>>> Patch 1 and Patch 2 was provided by Marc on his NV series[1] patches,
>>>> which detect the TTL feature and add __tlbi_level interface.
>>>
>>> I realy hate how it makes vma->vm_flags more important for tlbi.
>>>
>>
>> Thanks for your review.
>>
>> The tlbi interfaces only have two parameters: vma and addr. If we
>> try to not use vma->vm_flags, we may should have to add a parameter
>> to some of these interfaces(such as flush_tlb_range), which are
>> common to all architectures.
>>
>> I'm not sure if this is feasible, because this feature is only
>> supported by ARM64 currently.
> 
> Power (p9-radix) also has level dependent invalidation instructions, so
> at the very least you can hook them up as well.
> 
> .
>

Thanks, I will push my next version soon.

Zhenyu
.