Re: [PATCH v3 11/11] x86/mm: Try to preserve old TLB entries using PCID

[Andy Lutomirski]

On Thu, Jun 22, 2017 at 9:09 AM, Nadav Amit <nadav.amit@xxxxxxxxx> wrote:
> Andy Lutomirski <luto@xxxxxxxxxx> wrote:
>
>>
>> --- a/arch/x86/mm/init.c
>> +++ b/arch/x86/mm/init.c
>> @@ -812,6 +812,7 @@ void __init zone_sizes_init(void)
>>
>> DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
>>       .loaded_mm = &init_mm,
>> +     .next_asid = 1,
>
> I think this is a remainder from previous version of the patches, no? It
> does not seem necessary and may be confusing (ctx_id 0 is reserved, but not
> asid 0).

Hmm.  It's no longer needed for correctness, but init_mm still lands
in slot 0, and it seems friendly to avoid immediately stomping it.
Admittedly, this won't make any practical difference since it'll only
happen once per cpu.

>
> Other than that, if you want, you can put for the entire series:
>
> Reviewed-by: Nadav Amit <nadav.amit@xxxxxxxxx>
>

Thanks!