Re: [PATCH v2] KVM: x86: count actual tlb flushes

[Liang Chen <liangchen.linux@gmail.com>]

On 09/18/2014 10:00 AM, Radim Krčmář wrote:
> 2014-09-17 14:35-0400, Liang Chen:
>> - we count KVM_REQ_TLB_FLUSH requests, not actual flushes
>> (KVM can have multiple requests for one flush)
>> - flushes from kvm_flush_remote_tlbs aren't counted
>> - it's easy to make a direct request by mistake
>>
>> Solve these by postponing the counting to kvm_check_request(),
>> and refactor the code to use kvm_make_request again.
>>
>> Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
>> ---
>> Changes since v2:
>>
>> * Instead of calling kvm_mmu_flush_tlb everywhere to make sure the
>> stat is always incremented, postponing the counting to
>> kvm_check_request.
>>
>> (The idea comes from Radim. Much of the work is indeed done by him
>> and is included in this patch, otherwise I couldn't start working
>> on the followup work as I promised early. As I'm new to kvm
>> development, please let me know if I am doing wrong here.)
> I found (shame on me) Documentation/development-process/ when looking
> how to help and it looks really good.
> (If you read it, the rest of my mail will be obsolete :)
>
> You usually want to Cc linux-kernel@vger.kernel.org.
> (I've heard that someone actually reads it directly and it is a good
>  archive otherwise.  It allows people to `git blame` your code and find
>  the discussion in their preferred mail reader.)
>
> The hard part about posting a patch is splitting it ...
> You want to separate logical changes to make the code maintainable:
> For this patch, I would create at least two-part series (cover letter!)
>
>  - change the meaning of tlb_flush
>  - refactor code
>
> And see if it would make sense to split the refactoring further or if it
> breaks when only a first part of the whole series is applied.
>
> It's not a problem if your code depends on unmerged patches, you can
> include someone else's code in the series as long as it isn't modified.
> (Which probably is better than just mentioning that your code depends on
>  some other patches from the list, but I'm not applying it ... Paolo?)

Thank you very much for the help! Creating a patch series and including
your patch intact as the first one sound to be the best ;)

Thanks,
Liang