Re: [Qemu-devel] [PATCH v7 16/27] cputlb: add tlb_flush_by_mmuidx async routines

[Alex Bennée]

Richard Henderson <address@hidden> writes:

> On 01/24/2017 12:31 PM, Alex Bennée wrote:
>>> Why don't we just pass in this bitmap in the first place?  It's much better
>>> than having to use varargs in tlb_flush_by_mmuidx...
>>
>> We could. By not messing with the API it leaves the door open to having
>> other non-MTTCG architectures that have lots of MMU indexes versus a
>> hard limit based on page-size. That said I think the number of indexes
>> also affects the size of the TLB so I guess the current design is
>> limited for arbitrarily large sets if indexes?
>
> We hard-limit at 12 indices, though even that is arguably too high.
> I hope we never see more than PPC's current 8.

Hmm there is quite a lot of churn in the ARM code to move from an index
to a bitmap. It should be mostly mechanical but we'll see.

--
Alex Bennée