* Peter Xu (pet...@redhat.com) wrote:
> On Wed, Jun 13, 2018 at 11:26:41AM +0100, Dr. David Alan Gilbert (git) wrote:
>
> [...]
>
> > @@ -2932,10 +2943,24 @@ static void *migration_thread(void *opaque)
> >
> > migration_update_counters(s, current_time);
> >
> > + urgent = false;
> > if (qemu_file_rate_limit(s->to_dst_file)) {
> > - /* usleep expects microseconds */
> > - g_usleep((s->iteration_start_time + BUFFER_DELAY -
> > - current_time) * 1000);
> > + /* Wait for a delay to do rate limiting OR
> > + * something urgent to post the semaphore.
> > + */
> > + int ms = s->iteration_start_time + BUFFER_DELAY - current_time;
> > + trace_migration_thread_ratelimit_pre(ms);
> > + if (qemu_sem_timedwait(&s->rate_limit_sem, ms) == 0) {
> > + /* We were worken by one or more urgent things but
> > + * the timedwait will have consumed one of them.
> > + * The service routine for the urgent wake will dec
> > + * the semaphore itself for each item it consumes,
> > + * so add this one we just eat back.
> > + */
> > + qemu_sem_post(&s->rate_limit_sem);
>
> Is it possible that we just avoid eating that in the next patch? Then
> we only provide a helper to "trigger an urgent request" but we only
> consume the point here?
I think it's harder;
This code is generic in migration.c where as the next patch is all
specific in ram.c; so we'd have to push a flag all the way down.
Also, the code later is very simple - every request it adds/removes
it posts/waits the semaphore - it's nice to keep that simple.
Dave
> --
> Peter Xu
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
