On 05/15/2014 03:39 AM, Dongsheng Yang wrote:
As shown in 'man virsh' about schedinfo:
Note: The cpu_shares parameter has a valid value range of 0-262144;
This note documents historical kernel limits; if the kernel has changed, this may be out of date.
Because when we set the value of cpu_shares, when flag is --live, write the value into cgroup/cpu.shares. Then it will convert the value into the range of [2, 262144]. When flag is --config, we set the value into vmdef immidiately and 0 means no settting for
s/immidiately/immediately/ s/settting/setting/
cpu_shares. When we start vm again, libvirt use default value(1024)
s/use/uses/
for it.
This patch clamp the cpu_shares value when flag is --config, then
s/clamp/clamps/
we will get then "correct" settting in output of virsh schedinfo
s/settting/setting/
and value in cgroup after next booting of vm.
+++ b/src/qemu/qemu_driver.c @@ -112,6 +112,8 @@ VIR_LOG_INIT("qemu.qemu_driver"); #define QEMU_SCHED_MAX_PERIOD 1000000LL #define QEMU_SCHED_MIN_QUOTA 1000LL #define QEMU_SCHED_MAX_QUOTA 18446744073709551LL +#define QEMU_SCHED_MIN_SHARES 2LL +#define QEMU_SCHED_MAX_SHARES 262144LL
I'm a bit reluctant to add these numbers - if the kernel ever changes its range again (which HAS happened for some cgroup tunables), then we are needlessly preventing use of the newer range. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org