Re: [libvirt] [PATCH] qemu: Pin the emulator when only cpuset is specified

On 2012年10月17日 23:38, Martin Kletzander wrote: > According to our recent changes (clarifications), we should be pinning > qemu's emulator processes using the<vcpu> 'cpuset' attribute in case > there is no<emulatorpin> specified. This however doesn't work > entirely as expected and this patch should resolve all the remaining > issues. > --- > src/qemu/qemu_cgroup.c | 25 ++++++++++++++++--------- > src/qemu/qemu_cgroup.h | 4 ++-- > src/qemu/qemu_driver.c | 3 ++- > src/qemu/qemu_process.c | 16 ++++++++-------- > 4 files changed, 28 insertions(+), 20 deletions(-) >

> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c > index a94e9c4..e08ec67 100644 > --- a/src/qemu/qemu_process.c > +++ b/src/qemu/qemu_process.c > @@ -2024,11 +2024,12 @@ cleanup: > return ret; > } > > -/* Set CPU affinities for emulator threads if emulatorpin xml > provided. */ > +/* Set CPU affinities for emulator threads. */ > static int > qemuProcessSetEmulatorAffinites(virConnectPtr conn, > virDomainObjPtr vm) > { > + virBitmapPtr cpumask; > virDomainDefPtr def = vm->def; > virNodeInfo nodeinfo; > int ret = -1; > @@ -2036,15 +2037,14 @@ qemuProcessSetEmulatorAffinites(virConnectPtr > conn, > if (virNodeGetInfo(conn,&nodeinfo) != 0) > return -1; > > - if (!def->cputune.emulatorpin) > - return 0; > - > - if (virProcessInfoSetAffinity(vm->pid, > - > def->cputune.emulatorpin->cpumask)< 0) { > + if (def->cputune.emulatorpin) > + cpumask = def->cputune.emulatorpin->cpumask; > + else if (def->cpumask) > + cpumask = def->cpumask; > + else > goto cleanup; > - } > > - ret = 0; > + ret = virProcessInfoSetAffinity(vm->pid, cpumask); > cleanup: > return ret; > } This patch actually duplicates the affinity setting on domain process with sched_setaffinity. Assume "cpuset" of <vcpu> is specified, and no "<emulatorpin>". qemuProcessInitCpuAffinity is excuted between the fork and exec, with this patch, qemuProcessSetEmulatorAffinites will set the affinity again using sched_setaffinity. Cgroup setting is fine though, as there is no previous setting with cgroup. I'm wondering why the domain process is not pinned to pCPUs specified "cpuset" of "<vcpu>" by qemuProcessInitCpuAffinity, when <emulatorpin> is not specified. Regards, Osier