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

[Kunkun Jiang]

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?

Thanks,
Kunkun Jiang