github.com/blixtra/rkt@v0.8.1-0.20160204105720-ab0d1add1a43/stage1/init/kvm/resources.go (about)

     1  // Copyright 2015 The rkt Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package kvm
    16  
    17  import (
    18  	"runtime"
    19  
    20  	"github.com/appc/spec/schema"
    21  	"github.com/appc/spec/schema/types"
    22  )
    23  
    24  const (
    25  	defaultMem        = 128 // MB
    26  	systemMemOverhead = 128 // MB
    27  )
    28  
    29  // findResources finds value of last isolator for particular type.
    30  func findResources(isolators types.Isolators) (mem, cpus int64) {
    31  	mem = defaultMem
    32  	for _, i := range isolators {
    33  		switch v := i.Value().(type) {
    34  		case *types.ResourceMemory:
    35  			mem = v.Limit().Value()
    36  			// Convert bytes into megabytes
    37  			mem /= 1024 * 1024
    38  		case *types.ResourceCPU:
    39  			cpus = v.Limit().Value()
    40  		}
    41  	}
    42  	return mem, cpus
    43  }
    44  
    45  // GetAppsResources returns values specified by user in pod-manifest.
    46  // Function expects a podmanifest apps.
    47  // Return aggregate quantity of mem (in MB) and cpus.
    48  func GetAppsResources(apps schema.AppList) (totalCpus, totalMem int64) {
    49  	cpusSpecified := false
    50  	for i := range apps {
    51  		ra := &apps[i]
    52  		app := ra.App
    53  		mem, cpus := findResources(app.Isolators)
    54  		cpusSpecified = cpusSpecified || cpus != 0
    55  		totalCpus += cpus
    56  		totalMem += mem
    57  	}
    58  	// If user doesn't specify cpus for at least one app, we set no limit for
    59  	// whole pod.
    60  	if !cpusSpecified {
    61  		totalCpus = int64(runtime.NumCPU())
    62  	}
    63  
    64  	// Add an overhead for the VM system
    65  	totalMem += systemMemOverhead
    66  
    67  	return totalCpus, totalMem
    68  }