config: don't exceed the number of physical cores

Julio Montes · Julio Montes · commit f6da5370462b · 2018-02-23T13:24:45.000-06:00
the maximum number of vCPUs per VM shouldn't not exceed the number of physical cores, otherwise we could face issues with KVM and other architectures fixes #1028 Signed-off-by: Julio Montes <julio.montes@intel.com>
diff --git a/config.go b/config.go
@@ -185,15 +185,14 @@ func (h hypervisor) machineType() string {
 }
 
 func (h hypervisor) defaultVCPUs() uint32 {
-	if h.DefaultVCPUs < 0 {
-		return uint32(goruntime.NumCPU())
+	numCPUs := goruntime.NumCPU()
+
+	if h.DefaultVCPUs < 0 || h.DefaultVCPUs > int32(numCPUs) {
+		return uint32(numCPUs)
 	}
 	if h.DefaultVCPUs == 0 { // or unspecified
 		return defaultVCPUCount
 	}
-	if h.DefaultVCPUs > 255 { // qemu supports max 255
-		return 255
-	}
 
 	return uint32(h.DefaultVCPUs)
 }
diff --git a/config/configuration.toml.in b/config/configuration.toml.in
@@ -33,10 +33,10 @@ firmware = "@FIRMWAREPATH@"
 machine_accelerators="@MACHINEACCELERATORS@"
 
 # Default number of vCPUs per POD/VM:
-# unspecified or 0 --> will be set to @DEFVCPUS@
-# < 0              --> will be set to the actual number of physical cores
-# > 0 <= 255       --> will be set to the specified number
-# > 255            --> will be set to 255
+# unspecified or 0                --> will be set to @DEFVCPUS@
+# < 0                             --> will be set to the actual number of physical cores
+# > 0 <= number of physical cores --> will be set to the specified number
+# > number of physical cores      --> will be set to the actual number of physical cores
 default_vcpus = -1
 
 
diff --git a/config_test.go b/config_test.go
@@ -668,9 +668,9 @@ func TestHypervisorDefaults(t *testing.T) {
 	h.DefaultVCPUs = 2
 	assert.Equal(h.defaultVCPUs(), uint32(2), "default vCPU number is wrong")
 
-	// qemu supports max 255
-	h.DefaultVCPUs = 8086
-	assert.Equal(h.defaultVCPUs(), uint32(255), "default vCPU number is wrong")
+	numCPUs := goruntime.NumCPU()
+	h.DefaultVCPUs = int32(numCPUs) + 1
+	assert.Equal(h.defaultVCPUs(), uint32(numCPUs), "default vCPU number is wrong")
 
 	h.DefaultMemSz = 1024
 	assert.Equal(h.defaultMemSz(), uint32(1024), "default memory size is wrong")
@@ -1017,7 +1017,7 @@ func TestUpdateRuntimeConfiguration(t *testing.T) {
 func TestUpdateRuntimeConfigurationVMConfig(t *testing.T) {
 	assert := assert.New(t)
 
-	vcpus := uint(8)
+	vcpus := uint(2)
 	mem := uint(2048)
 
 	config := oci.RuntimeConfig{}

Original file line number	Diff line number	Diff line change
`@@ -185,15 +185,14 @@ func (h hypervisor) machineType() string {`
`185`	`185`	`}`
`186`	`186`
`187`	`187`	`func (h hypervisor) defaultVCPUs() uint32 {`
`188`		`- if h.DefaultVCPUs < 0 {`
`189`		`- return uint32(goruntime.NumCPU())`
	`188`	`+ numCPUs := goruntime.NumCPU()`
	`189`	`+`
	`190`	`+ if h.DefaultVCPUs < 0 \|\| h.DefaultVCPUs > int32(numCPUs) {`
	`191`	`+ return uint32(numCPUs)`
`190`	`192`	`}`
`191`	`193`	`if h.DefaultVCPUs == 0 { // or unspecified`
`192`	`194`	`return defaultVCPUCount`
`193`	`195`	`}`
`194`		`- if h.DefaultVCPUs > 255 { // qemu supports max 255`
`195`		`- return 255`
`196`		`- }`
`197`	`196`
`198`	`197`	`return uint32(h.DefaultVCPUs)`
`199`	`198`	`}`