Re: [PATCH v4 1/2] migration/ram: Reduce unnecessary rate limiting

[David Edmondson <dme@dme.org>]

On Wednesday, 2021-03-17 at 09:37:11 +08, Kunkun Jiang wrote:

> Hi  Peter,
>
> On 2021/3/17 5:39, Peter Xu wrote:
>> On Tue, Mar 16, 2021 at 08:57:15PM +0800, Kunkun Jiang wrote:
>>> When the host page is a huge page and something is sent in the
>>> current iteration, migration_rate_limit() should be executed.
>>> If not, it can be omitted.
>>>
>>> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
>>> Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
>>> Reviewed-by: David Edmondson <david.edmondson@oracle.com>
>>> ---
>>>   migration/ram.c | 9 +++++++--
>>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/migration/ram.c b/migration/ram.c
>>> index 72143da0ac..3eb5b0d7a7 100644
>>> --- a/migration/ram.c
>>> +++ b/migration/ram.c
>>> @@ -2015,8 +2015,13 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
>>>   
>>>           pages += tmppages;
>>>           pss->page++;
>>> -        /* Allow rate limiting to happen in the middle of huge pages */
>>> -        migration_rate_limit();
>>> +        /*
>>> +         * Allow rate limiting to happen in the middle of huge pages if
>>> +         * something is sent in the current iteration.
>>> +         */
>>> +        if (pagesize_bits > 1 && tmppages > 0) {
>>> +            migration_rate_limit();
>>> +        }
>> Sorry I'm still not a fan of this - I'd even prefer calling that once more just
>> to make sure it won't be forgotten to be called..  Not to say it's merely a noop.
>>
>> I'll leave this to Dave..  Maybe I'm too harsh! :)
>>
> You are very serious and meticulous. I like your character very much.😉
> This patch was used to reviewed by David. So, I want to know what
> his opinion is.
>
> @David
> Hi David, what is your opinion on this patch?

I suspect that this referred to David Gilbert rather than me :-)

> Thanks,
> Kunkun Jiang

dme.
-- 
Time is waiting to explain, why refuse?