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Subject: Re: Re: [RFC PATCH v4 0/6] arm64: tlb: add support for TTL feature
To:     Peter Zijlstra <peterz@infradead.org>
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References: <20200324134534.1570-1-yezhenyu2@huawei.com>
 <20200324150155.GH20713@hirez.programming.kicks-ass.net>
From:   Zhenyu Ye <yezhenyu2@huawei.com>
Message-ID: <fb06ba92-a3ce-6925-e914-167a85837f27@huawei.com>
Date:   Wed, 25 Mar 2020 12:49:45 +0800
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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.


Thanks,
Zhenyu