On 10/04/2013 04:13 PM, Paolo Bonzini wrote: > Il 04/10/2013 02:04, Marcelo Tosatti ha scritto: >>>>>> This QMP command allows user set guest node's memory policy >>>>>> through the QMP protocol. The qmp-shell command is like: >>>>>> set-mem-policy nodeid=0 policy=membind relative=true host-nodes=0-1 >>>>>> >>>>>> Reviewed-by: Luiz Capitulino <lcapitul...@redhat.com> >>>>>> Signed-off-by: Wanlong Gao <gaowanl...@cn.fujitsu.com> >>>> >>>> Wanlong Gao, >>>> >>>> 1) >>>> >>>> Exposing mbind via QMP/HMP on a live guest is interesting because, >>>> see mbind manpage: >>>> >>>> "By default, mbind() only has an effect for new allocations; >>>> if the pages inside the range have been already touched before >>>> setting the policy, then the policy has no effect. This default >>>> behavior may be overridden by the MPOL_MF_MOVE and >>>> MPOL_MF_MOVE_ALL flags described below." >>>> >>>> This means that executing set-mem-policy on a live guest is >>>> unpredictable: it depends on which pages have been faulted in already. >>>> >>>> Should the command be restricted to offline guests? >> In fact, unless there is a missing point, it should be removed: to solve >> the device assignment case (memory pinning), mbind must be executed before >> the memory regions are registered. >> > > Right. We can add the command back later as memory-add, together with > memory hotplug.
OK, will remove the command in this patch set. Thanks, Wanlong Gao > > Paolo >
