On Wed, Oct 02, 2013 at 11:13:29PM -0300, Marcelo Tosatti wrote: > On Tue, Sep 17, 2013 at 11:16:22AM +0800, Wanlong Gao wrote: > > 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. > 2) > > Have you tested the patchset with hugetlbfs (-mem-path) backing ? >
