Re: [libvirt] [PATCH 2/5] Support CPU placement in LXC driver

On Thu, Nov 24, 2011 at 11:38:13AM +0000, Daniel P. Berrange wrote: > From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; > > While LXC does not have the concept of VCPUS, so we cann't do s/nn/n/ > per-VCPU pCPU placement, we can support the VM level CPU > placement. Todo this simply set the CPU affinity of the LXC > controller at startup. All child processes will inherit this > affinity. > > * src/lxc/lxc_controller.c: Set process affinity > --- > src/lxc/lxc_controller.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 63 insertions(+), 0 deletions(-) > > diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c > index 4718fa8..1db25fb 100644 > --- a/src/lxc/lxc_controller.c > +++ b/src/lxc/lxc_controller.c > @@ -66,6 +66,8 @@ > #include "virfile.h" > #include "virpidfile.h" > #include "command.h" > +#include "processinfo.h" > +#include "nodeinfo.h" > > #define VIR_FROM_THIS VIR_FROM_LXC > > @@ -322,6 +324,64 @@ static int lxcSetContainerNUMAPolicy(virDomainDefPtr def) > } > #endif > > + > +/* > + * To be run while still single threaded > + */ > +static int lxcSetContainerCpuAffinity(virDomainDefPtr def) > +{ > + int i, hostcpus, maxcpu = CPU_SETSIZE; > + virNodeInfo nodeinfo; > + unsigned char *cpumap; > + int cpumaplen; > + > + VIR_DEBUG("Setting CPU affinity"); > + > + if (nodeGetInfo(NULL, &nodeinfo) < 0) > + return -1; > + > + /* setaffinity fails if you set bits for CPUs which > + * aren't present, so we have to limit ourselves */ > + hostcpus = VIR_NODEINFO_MAXCPUS(nodeinfo); > + if (maxcpu > hostcpus) > + maxcpu = hostcpus; > + > + cpumaplen = VIR_CPU_MAPLEN(maxcpu); > + if (VIR_ALLOC_N(cpumap, cpumaplen) < 0) { > + virReportOOMError(); > + return -1; > + } > + > + if (def->cpumask) { > + /* XXX why don't we keep 'cpumask' in the libvirt cpumap > + * format to start with ?!?! */ > + for (i = 0 ; i < maxcpu && i < def->cpumasklen ; i++) > + if (def->cpumask[i]) > + VIR_USE_CPU(cpumap, i); > + } else { > + /* You may think this is redundant, but we can't assume libvirtd > + * itself is running on all pCPUs, so we need to explicitly set > + * the spawned QEMU instance to all pCPUs if no map is given in Hum you mean LXC container instead of QEmu, right ? > + * its config file */ > + for (i = 0 ; i < maxcpu ; i++) > + VIR_USE_CPU(cpumap, i); > + } > + > + /* We are pressuming we are running between fork/exec of QEMU idem