1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
// Copyright (c) 2022 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//go:build linux
// +build linux
package automaxprocs
import (
"bufio"
"errors"
"fmt"
"io"
"os"
"path"
"strconv"
"strings"
)
const (
// _cgroupv2CPUMax is the file name for the CGroup-V2 CPU max and period
// parameter.
_cgroupv2CPUMax = "cpu.max"
// _cgroupFSType is the Linux CGroup-V2 file system type used in
// `/proc/$PID/mountinfo`.
_cgroupv2FSType = "cgroup2"
_cgroupv2MountPoint = "/sys/fs/cgroup"
_cgroupV2CPUMaxDefaultPeriod = 100000
_cgroupV2CPUMaxQuotaMax = "max"
)
const (
_cgroupv2CPUMaxQuotaIndex = iota
_cgroupv2CPUMaxPeriodIndex
)
// ErrNotV2 indicates that the system is not using cgroups2.
var ErrNotV2 = errors.New("not using cgroups2")
// CGroups2 provides access to cgroups data for systems using cgroups2.
type CGroups2 struct {
mountPoint string
groupPath string
cpuMaxFile string
}
// NewCGroups2ForCurrentProcess builds a CGroups2 for the current process.
//
// This returns ErrNotV2 if the system is not using cgroups2.
func NewCGroups2ForCurrentProcess() (*CGroups2, error) {
return newCGroups2From(_procPathMountInfo, _procPathCGroup)
}
func newCGroups2From(mountInfoPath, procPathCGroup string) (*CGroups2, error) {
isV2, err := isCGroupV2(mountInfoPath)
if err != nil {
return nil, err
}
if !isV2 {
return nil, ErrNotV2
}
subsystems, err := parseCGroupSubsystems(procPathCGroup)
if err != nil {
return nil, err
}
// Find v2 subsystem by looking for the `0` id
var v2subsys *CGroupSubsys
for _, subsys := range subsystems {
if subsys.ID == 0 {
v2subsys = subsys
break
}
}
if v2subsys == nil {
return nil, ErrNotV2
}
return &CGroups2{
mountPoint: _cgroupv2MountPoint,
groupPath: v2subsys.Name,
cpuMaxFile: _cgroupv2CPUMax,
}, nil
}
func isCGroupV2(procPathMountInfo string) (bool, error) {
var (
isV2 bool
newMountPoint = func(mp *MountPoint) error {
isV2 = isV2 || (mp.FSType == _cgroupv2FSType && mp.MountPoint == _cgroupv2MountPoint)
return nil
}
)
if err := parseMountInfo(procPathMountInfo, newMountPoint); err != nil {
return false, err
}
return isV2, nil
}
// CPUQuota returns the CPU quota applied with the CPU cgroup2 controller.
// It is a result of reading cpu quota and period from cpu.max file.
// It will return `cpu.max / cpu.period`. If cpu.max is set to max, it returns
// (-1, false, nil)
func (cg *CGroups2) CPUQuota() (float64, bool, error) {
cpuMaxParams, err := os.Open(path.Join(cg.mountPoint, cg.groupPath, cg.cpuMaxFile))
if err != nil {
if os.IsNotExist(err) {
return -1, false, nil
}
return -1, false, err
}
defer cpuMaxParams.Close()
scanner := bufio.NewScanner(cpuMaxParams)
if scanner.Scan() {
fields := strings.Fields(scanner.Text())
if len(fields) == 0 || len(fields) > 2 {
return -1, false, fmt.Errorf("invalid format")
}
if fields[_cgroupv2CPUMaxQuotaIndex] == _cgroupV2CPUMaxQuotaMax {
return -1, false, nil
}
max, err := strconv.Atoi(fields[_cgroupv2CPUMaxQuotaIndex])
if err != nil {
return -1, false, err
}
var period int
if len(fields) == 1 {
period = _cgroupV2CPUMaxDefaultPeriod
} else {
period, err = strconv.Atoi(fields[_cgroupv2CPUMaxPeriodIndex])
if err != nil {
return -1, false, err
}
if period == 0 {
return -1, false, errors.New("zero value for period is not allowed")
}
}
return float64(max) / float64(period), true, nil
}
if err := scanner.Err(); err != nil {
return -1, false, err
}
return 0, false, io.ErrUnexpectedEOF
}
|
