Re: [libvirt] [v7 00/10] Support cache tune in libvirt

On Sun, Feb 19, 2017 at 12:20:55PM -0300, Marcelo Tosatti wrote: > On Sun, Feb 19, 2017 at 12:01:57PM -0300, Marcelo Tosatti wrote: > > > > How does the management software query the amount of allocatable cache > > again? > > > > Section from another discussion: > > > > > The second case is necessary to get updated free space information. > > > > Just VM initialization time could be enough as virConnectGetCapabilities > > would just know the total and free size would be reported in an API (if > > I rememer the discussion correctly) > > > > Martin > > Yes, i think this is missing because the interface was designed > with only libvirt in mind: the "reserved" field returns the amount of > cache reserved only by VMs. > > So if there is another application on the same L3 socket > with a cache reservation, "reserved" fails to report it. > > Eli can you expose the amount of free allocatable cache space > (where non-free includes space used by other reservations) in a > 'free_space' field in the cache output of virConnectGetCapabilities? > There should be an API for that instead. Capabilities are supposed to show what the hardware is capable of, not what the actual state is. If my opinion is not enough, see here: https://www.redhat.com/archives/libvir-list/2017-January/msg00500.html