Treat zero cpu shares as a valid value

Currently, <cputune><shares>0</shares></cputune> is treated
as if it were not specified.

Treat is as a valid value if it was explicitly specified
and write it to the cgroups.

src/conf/domain_conf.c

@@ -11543,11 +11543,13 @@ virDomainDefParseXML(xmlDocPtr xml,
     }
 
     /* Extract cpu tunables. */
-    if (virXPathULong("string(./cputune/shares[1])", ctxt,
-                      &def->cputune.shares) < -1) {
+    if ((n = virXPathULong("string(./cputune/shares[1])", ctxt,
+                           &def->cputune.shares)) < -1) {
         virReportError(VIR_ERR_XML_ERROR, "%s",
                        _("can't parse cputune shares value"));
         goto error;
+    } else if (n == 0) {
+        def->cputune.sharesSpecified = true;
     }
 
     if (virXPathULongLong("string(./cputune/period[1])", ctxt,
@@ -17276,7 +17278,7 @@ virDomainDefFormatInternal(virDomainDefPtr def,
         virBufferAsprintf(buf, " current='%u'", def->vcpus);
     virBufferAsprintf(buf, ">%u</vcpu>\n", def->maxvcpus);
 
-    if (def->cputune.shares ||
+    if (def->cputune.sharesSpecified ||
         (def->cputune.nvcpupin && !virDomainIsAllVcpupinInherited(def)) ||
         def->cputune.period || def->cputune.quota ||
         def->cputune.emulatorpin ||
@@ -17284,7 +17286,7 @@ virDomainDefFormatInternal(virDomainDefPtr def,
         virBufferAddLit(buf, "<cputune>\n");
 
     virBufferAdjustIndent(buf, 2);
-    if (def->cputune.shares)
+    if (def->cputune.sharesSpecified)
         virBufferAsprintf(buf, "<shares>%lu</shares>\n",
                           def->cputune.shares);
     if (def->cputune.period)
@@ -17339,7 +17341,7 @@ virDomainDefFormatInternal(virDomainDefPtr def,
         VIR_FREE(cpumask);
     }
     virBufferAdjustIndent(buf, -2);
-    if (def->cputune.shares ||
+    if (def->cputune.sharesSpecified ||
         (def->cputune.nvcpupin && !virDomainIsAllVcpupinInherited(def)) ||
         def->cputune.period || def->cputune.quota ||
         def->cputune.emulatorpin ||

src/conf/domain_conf.h

@@ -2011,6 +2011,7 @@ struct _virDomainDef {
 
     struct {
         unsigned long shares;
+        bool sharesSpecified;
         unsigned long long period;
         long long quota;
         unsigned long long emulator_period;

src/lxc/lxc_cgroup.c

@@ -38,7 +38,7 @@ static int virLXCCgroupSetupCpuTune(virDomainDefPtr def,
                                     virCgroupPtr cgroup)
 {
     int ret = -1;
-    if (def->cputune.shares != 0 &&
+    if (def->cputune.sharesSpecified &&
         virCgroupSetCpuShares(cgroup, def->cputune.shares) < 0)
         goto cleanup;
 

src/lxc/lxc_driver.c

@@ -1902,10 +1902,12 @@ lxcDomainSetSchedulerParametersFlags(virDomainPtr dom,
                     goto cleanup;
 
                 vm->def->cputune.shares = params[i].value.ul;
+                vm->def->cputune.sharesSpecified = true;
             }
 
             if (flags & VIR_DOMAIN_AFFECT_CONFIG) {
                 vmdef->cputune.shares = params[i].value.ul;
+                vmdef->cputune.sharesSpecified = true;
             }
         } else if (STREQ(param->field, VIR_DOMAIN_SCHEDULER_VCPU_PERIOD)) {
             if (flags & VIR_DOMAIN_AFFECT_LIVE) {

src/lxc/lxc_native.c

@@ -678,9 +678,11 @@ lxcSetCpuTune(virDomainDefPtr def, virConfPtr properties)
     virConfValuePtr value;
 
     if ((value = virConfGetValue(properties, "lxc.cgroup.cpu.shares")) &&
-            value->str && virStrToLong_ul(value->str, NULL, 10,
-                                          &def->cputune.shares) < 0)
-        goto error;
+            value->str) {
+        if (virStrToLong_ul(value->str, NULL, 10, &def->cputune.shares) < 0)
+            goto error;
+        def->cputune.sharesSpecified = true;
+    }
 
     if ((value = virConfGetValue(properties,
                                  "lxc.cgroup.cpu.cfs_quota_us")) &&

src/parallels/parallels_driver.c

@@ -2051,6 +2051,7 @@ parallelsApplyChanges(virConnectPtr conn, virDomainObjPtr dom, virDomainDefPtr n
     }
 
     if (old->cputune.shares != new->cputune.shares ||
+        old->cputune.sharesSpecified != new->cputune.sharesSpecified ||
         old->cputune.period != new->cputune.period ||
         old->cputune.quota != new->cputune.quota ||
         old->cputune.nvcpupin != new->cputune.nvcpupin) {

src/qemu/qemu_cgroup.c

@@ -646,7 +646,7 @@ qemuSetupCpuCgroup(virDomainObjPtr vm)
     qemuDomainObjPrivatePtr priv = vm->privateData;
 
     if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPU)) {
-       if (vm->def->cputune.shares) {
+       if (vm->def->cputune.sharesSpecified) {
            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                           _("CPU tuning is not available on this host"));
            return -1;
@@ -655,7 +655,7 @@ qemuSetupCpuCgroup(virDomainObjPtr vm)
        }
     }
 
-    if (vm->def->cputune.shares &&
+    if (vm->def->cputune.sharesSpecified &&
         virCgroupSetCpuShares(priv->cgroup, vm->def->cputune.shares) < 0)
         return -1;
 

src/qemu/qemu_command.c

@@ -7784,7 +7784,7 @@ qemuBuildCommandLine(virConnectPtr conn,
             goto error;
         }
 
-        if (def->cputune.shares || def->cputune.period ||
+        if (def->cputune.sharesSpecified || def->cputune.period ||
             def->cputune.quota || def->cputune.emulator_period ||
             def->cputune.emulator_quota) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",

src/qemu/qemu_driver.c

@@ -9088,10 +9088,14 @@ qemuDomainSetSchedulerParametersFlags(virDomainPtr dom,
                 if (virCgroupSetCpuShares(priv->cgroup, value_ul) < 0)
                     goto cleanup;
                 vm->def->cputune.shares = value_ul;
+                vm->def->cputune.sharesSpecified = true;
             }
 
-            if (flags & VIR_DOMAIN_AFFECT_CONFIG)
+            if (flags & VIR_DOMAIN_AFFECT_CONFIG) {
                 vmdef->cputune.shares = value_ul;
+                vmdef->cputune.sharesSpecified = true;
+            }
+
 
         } else if (STREQ(param->field, VIR_DOMAIN_SCHEDULER_VCPU_PERIOD)) {
             SCHED_RANGE_CHECK(value_ul, VIR_DOMAIN_SCHEDULER_VCPU_PERIOD,

src/vmx/vmx.c

@@ -1511,6 +1511,7 @@ virVMXParseConfig(virVMXContext *ctx,
                              "found '%s'"), sched_cpu_shares);
             goto cleanup;
         }
+        def->cputune.sharesSpecified = true;
     }
 
     /* def:lifecycle */
@@ -3196,7 +3197,7 @@ virVMXFormatConfig(virVMXContext *ctx, virDomainXMLOptionPtr xmlopt, virDomainDe
     }
 
     /* def:cputune.shares -> vmx:sched.cpu.shares */
-    if (def->cputune.shares > 0) {
+    if (def->cputune.sharesSpecified) {
         /* See http://www.vmware.com/support/developer/vc-sdk/visdk41pubs/ApiReference/vim.SharesInfo.Level.html */
         if (def->cputune.shares == def->vcpus * 500) {
             virBufferAddLit(&buffer, "sched.cpu.shares = \"low\"\n");

tests/qemuxml2argvdata/qemuxml2argv-cputune-zero-shares.args

+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \
+/usr/bin/qemu \
+-name QEMUGuest1 -S -M pc -m 214 -smp 2 -nographic \
+-monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -usb \
+-hda /dev/HostVG/QEMUGuest1 -net none -serial none -parallel none

tests/qemuxml2argvdata/qemuxml2argv-cputune-zero-shares.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>2</vcpu>
+  <cputune>
+    <shares>0</shares>
+    <period>1000000</period>
+    <quota>-1</quota>
+    <vcpupin vcpu='0' cpuset='0'/>
+    <vcpupin vcpu='1' cpuset='1'/>
+    <emulatorpin cpuset='1'/>
+  </cputune>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1163,6 +1163,7 @@ mymain(void)
     DO_TEST("blkiotune", QEMU_CAPS_NAME);
     DO_TEST("blkiotune-device", QEMU_CAPS_NAME);
     DO_TEST("cputune", QEMU_CAPS_NAME);
+    DO_TEST("cputune-zero-shares", QEMU_CAPS_NAME);
     DO_TEST("numatune-memory", NONE);
     DO_TEST("numatune-auto-nodeset-invalid", NONE);
     DO_TEST("numad", NONE);

tests/qemuxml2xmltest.c

@@ -260,6 +260,7 @@ mymain(void)
     DO_TEST("blkiotune");
     DO_TEST("blkiotune-device");
     DO_TEST("cputune");
+    DO_TEST("cputune-zero-shares");
 
     DO_TEST("smp");
     DO_TEST("lease");