[libvirt] [PATCH v2 4/4] virsh: add --persistent to cmd schedinfo

Hu Tao hutao at cn.fujitsu.com
Tue May 10 01:31:56 UTC 2011


On Mon, May 09, 2011 at 05:37:04PM +0800, Osier Yang wrote:
> 于 2011年05月09日 16:31, Hu Tao 写道:
> >This enables user to modify cpu.shares even when domain is inactive.
> >---
> >  tools/virsh.c |   14 +++++++++++++-
> >  1 files changed, 13 insertions(+), 1 deletions(-)
> >
> >diff --git a/tools/virsh.c b/tools/virsh.c
> >index 2b16714..58facc4 100644
> >--- a/tools/virsh.c
> >+++ b/tools/virsh.c
> >@@ -1590,6 +1590,7 @@ static const vshCmdOptDef opts_schedinfo[] = {
> >      {"set", VSH_OT_STRING, VSH_OFLAG_NONE, N_("parameter=value")},
> >      {"weight", VSH_OT_INT, VSH_OFLAG_NONE, N_("weight for XEN_CREDIT")},
> >      {"cap", VSH_OT_INT, VSH_OFLAG_NONE, N_("cap for XEN_CREDIT")},
> >+    {"persistent", VSH_OT_BOOL, 0, N_("persist VM on destination")},
> >      {NULL, 0, 0, NULL}
> >  };
> >
> >@@ -1697,6 +1698,7 @@ cmdSchedinfo(vshControl *ctl, const vshCmd *cmd)
> >      int update = 0;
> >      int i, ret;
> >      bool ret_val = false;
> >+    unsigned int flags = 0;
> >
> >      if (!vshConnectionUsability(ctl, ctl->conn))
> >          return false;
> >@@ -1704,6 +1706,16 @@ cmdSchedinfo(vshControl *ctl, const vshCmd *cmd)
> >      if (!(dom = vshCommandOptDomain(ctl, cmd, NULL)))
> >          return false;
> >
> >+    if (vshCommandOptBool(cmd, "persistent"))
> >+        flags |= VIR_DOMAIN_SCHEDPARAM_CONFIG;
> >+    if (virDomainIsActive(dom))
> >+        flags |= VIR_DOMAIN_SCHEDPARAM_LIVE;
> >+
> >+    if (!(flags&  (VIR_DOMAIN_SCHEDPARAM_CONFIG | VIR_DOMAIN_SCHEDPARAM_LIVE))) {
> >+        vshError(ctl, "%s", _("Domain is not running and you didn't specify --persistent parameter."));
> >+        goto cleanup;
> >+    }
> >+
> >      /* Print SchedulerType */
> >      schedulertype = virDomainGetSchedulerType(dom,&nparams);
> 
> Hi HuTao,
> 
> AFAIK, virDomainGetSchedulerParameters won't work for inactive domain,
> cgroup for domain is removed when the domain is destroyed/shutdown'ed,
> (perhaps we will support persistent XML for domain cgroup, but currently
> it doesn't), means it will fail earlier, before could executing
> virDomainSetSchedulerParametersFlags.

Yes, virDomainGetSchedulerParameters tries to read cpu.shares value
from domain's cgroup entry which doesn't exist when domain is off.
But, IMHO, the configuration (cpu.shares) should not depend on whether
domain is on or not. When domain is off, we can read/write the value
from/to its XML(domain.cputune.shares is already for this). What's
your opinion?

> 
> Actually I made similar patches about one month before:
> 
> https://www.redhat.com/archives/libvir-list/2011-April/msg00806.html

Thanks, I will take a look at it.

> 
> the difference with your patches is it only allows changing on running
> domain, options are "--live" and "--persistent", perhaps your principle
> is better though. :)
> 




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