Re: [PATCH RFC v2 5/6] KVM: moving dirty bitmaps to user space

Avi Kivity
2010-04-23T10:28:58Z

On 04/22/2010 12:07 PM, Takuya Yoshikawa wrote:
>
>>
>>> + slots->memslots[i].dirty_bitmap = NULL;
>>> + slots->memslots[i].dirty_bitmap_old = NULL;
>>> kvm_free_physmem_slot(&slots->memslots[i], NULL);
>>> + }
>>>
>>>
>>> +/*
>>> + * Please use generic *_user bitops once they become available.
>>> + * Be careful setting the bit won't be done atomically.
>>> + */
>>
>> Please introduce the user bitops as part of this patchset.
>>
>
> OK, I will do in the next version. In this RFC, I would be happy if I can
> know the overall design is right or not.
>

Everything looks reasonable to me.

Do you have performance numbers? I'm interested in both measurements of
KVM_SWITCH_DIRTY_LOG under various conditions and macro benchmarks (for
example, total guest throughput improvement under Kemari).

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.