On Thu 11 May 2017 04:41:57 PM CEST, Paolo Bonzini wrote:
> Starting all waiting coroutines from bdrv_drain_all is unnecessary;
> throttle_group_co_io_limits_intercept calls schedule_next_request as
> soon as the coroutine restarts, which in turn will restart the next
> request if possible.
>
> If we only start the first request and let the coroutines dance from
> there the code is simpler and there is more reuse between
> throttle_group_config, throttle_group_restart_blk and timer_cb. The
> next patch will benefit from this.
>
> We also stop accessing from throttle_group_restart_blk the
> blkp->throttled_reqs CoQueues even when there was no
> attached throttling group. This worked but is not pretty.
>
> The only thing that can interrupt the dance is the QEMU_CLOCK_VIRTUAL
> timer when switching from one block device to the next, because the
> timer is set to "now + 1" but QEMU_CLOCK_VIRTUAL might not be running.
> Set that timer to point in the present ("now") rather than the future
> and things work.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Alberto Garcia <be...@igalia.com>
Berto
