gotosocial/vendor/github.com/containerd/cgroups/systemd.go
Daniele Sluijters acc333c40b
[feature] Inherit resource limits from cgroups (#1336)
When GTS is running in a container runtime which has configured CPU or
memory limits or under an init system that uses cgroups to impose CPU
and memory limits the values the Go runtime sees for GOMAXPROCS and
GOMEMLIMIT are still based on the host resources, not the cgroup.

At least for the throttling middlewares which use GOMAXPROCS to
configure their queue size, this can result in GTS running with values
too big compared to the resources that will actuall be available to it.

This introduces 2 dependencies which can pick up resource contraints
from the current cgroup and tune the Go runtime accordingly. This should
result in the different queues being appropriately sized and in general
more predictable performance. These dependencies are a no-op on
non-Linux systems or if running in a cgroup that doesn't set a limit on
CPU or memory.

The automatic tuning of GOMEMLIMIT can be disabled by either explicitly
setting GOMEMLIMIT yourself or by setting AUTOMEMLIMIT=off. The
automatic tuning of GOMAXPROCS can similarly be counteracted by setting
GOMAXPROCS yourself.
2023-01-17 20:59:04 +00:00

159 lines
4 KiB
Go

/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package cgroups
import (
"context"
"path/filepath"
"strings"
"sync"
systemdDbus "github.com/coreos/go-systemd/v22/dbus"
"github.com/godbus/dbus/v5"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
const (
SystemdDbus Name = "systemd"
defaultSlice = "system.slice"
)
var (
canDelegate bool
once sync.Once
)
func Systemd() ([]Subsystem, error) {
root, err := v1MountPoint()
if err != nil {
return nil, err
}
defaultSubsystems, err := defaults(root)
if err != nil {
return nil, err
}
s, err := NewSystemd(root)
if err != nil {
return nil, err
}
// make sure the systemd controller is added first
return append([]Subsystem{s}, defaultSubsystems...), nil
}
func Slice(slice, name string) Path {
if slice == "" {
slice = defaultSlice
}
return func(subsystem Name) (string, error) {
return filepath.Join(slice, name), nil
}
}
func NewSystemd(root string) (*SystemdController, error) {
return &SystemdController{
root: root,
}, nil
}
type SystemdController struct {
mu sync.Mutex
root string
}
func (s *SystemdController) Name() Name {
return SystemdDbus
}
func (s *SystemdController) Create(path string, _ *specs.LinuxResources) error {
ctx := context.TODO()
conn, err := systemdDbus.NewWithContext(ctx)
if err != nil {
return err
}
defer conn.Close()
slice, name := splitName(path)
// We need to see if systemd can handle the delegate property
// Systemd will return an error if it cannot handle delegate regardless
// of its bool setting.
checkDelegate := func() {
canDelegate = true
dlSlice := newProperty("Delegate", true)
if _, err := conn.StartTransientUnitContext(ctx, slice, "testdelegate", []systemdDbus.Property{dlSlice}, nil); err != nil {
if dbusError, ok := err.(dbus.Error); ok {
// Starting with systemd v237, Delegate is not even a property of slices anymore,
// so the D-Bus call fails with "InvalidArgs" error.
if strings.Contains(dbusError.Name, "org.freedesktop.DBus.Error.PropertyReadOnly") || strings.Contains(dbusError.Name, "org.freedesktop.DBus.Error.InvalidArgs") {
canDelegate = false
}
}
}
_, _ = conn.StopUnitContext(ctx, slice, "testDelegate", nil)
}
once.Do(checkDelegate)
properties := []systemdDbus.Property{
systemdDbus.PropDescription("cgroup " + name),
systemdDbus.PropWants(slice),
newProperty("DefaultDependencies", false),
newProperty("MemoryAccounting", true),
newProperty("CPUAccounting", true),
newProperty("BlockIOAccounting", true),
}
// If we can delegate, we add the property back in
if canDelegate {
properties = append(properties, newProperty("Delegate", true))
}
ch := make(chan string)
_, err = conn.StartTransientUnitContext(ctx, name, "replace", properties, ch)
if err != nil {
return err
}
<-ch
return nil
}
func (s *SystemdController) Delete(path string) error {
ctx := context.TODO()
conn, err := systemdDbus.NewWithContext(ctx)
if err != nil {
return err
}
defer conn.Close()
_, name := splitName(path)
ch := make(chan string)
_, err = conn.StopUnitContext(ctx, name, "replace", ch)
if err != nil {
return err
}
<-ch
return nil
}
func newProperty(name string, units interface{}) systemdDbus.Property {
return systemdDbus.Property{
Name: name,
Value: dbus.MakeVariant(units),
}
}
func splitName(path string) (slice string, unit string) {
slice, unit = filepath.Split(path)
return strings.TrimSuffix(slice, "/"), unit
}