Re: [libvirt] [PATCH 5/6] qemu: Reduce memlock limit after detaching hostdev

On 11/24/2015 08:56 AM, Andrea Bolognani wrote: > We increase the limit before plugging in a PCI hostdev or a memory > module because some memory might need to be locked due to eg. VFIO. > > Of course we should do the opposite after unplugging a device: this > was already the case for memory modules, but not for hostdevs. > --- >  src/qemu/qemu_hotplug.c | 6 ++++++ >  1 file changed, 6 insertions(+) > > diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c > index a5c134a..04baeff 100644 > --- a/src/qemu/qemu_hotplug.c > +++ b/src/qemu/qemu_hotplug.c > @@ -3070,6 +3070,12 @@ qemuDomainRemoveHostDevice(virQEMUDriverPtr driver, >          networkReleaseActualDevice(vm->def, net); >          virDomainNetDefFree(net); >      } > + > +    /* QEMU might no longer need to lock as much memory, eg. we just detached > +     * a VFIO device, so adjust the limit here */ > +    if (qemuDomainAdjustMaxMemLock(vm) < 0) > +        VIR_WARN("Failed to adjust locked memory limit"); > + >      ret = 0; >   >   cleanup: > Since the add was in qemuDomainAttachHostPCIDevice, why is the remove not in qemuDomainDetachHostPCIDevice?  Doing it here would mean it's call for any host device removal - whether or not it was ever added.