On 04/17/2012 03:20 AM, Stefan Hajnoczi wrote: > I think it's cleanest to support block-job-set-speed even when no job > is running. The speed will be used as the default value when a job is > started. This poses the question of what happens if the job does not > do throttling or cannot support the value for some reason - does > creation fail until block-job-set-speed is set to 0 or a valid value > again, or do we allow it but silently perform no throttling?
I'd prefer failure for any request for an out-of-range speed, and I like the idea of always letting the user set the speed, even when a job is not already running. Am I correct that only one job can run at a time, and therefore, the speed can be a property associated with the BlockDevice as a whole, rather than only a property associated with each individual job? Libvirt would then implement virDomainBlockPull(dom, disk, bandwidth, flags) as a call to block-job-set-speed(bandwidth) followed by block-stream, rather than it's current implementation of block-stream followed by block-job-set-speed. And for the RHEL 6.2 implementation where things were spelled block_job_set_speed, libvirt will know that the old spelling implies that the speed has to be set second and live with the race that it implies. -- Eric Blake ebl...@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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