gotosocial/vendor/github.com/containerd/cgroups/freezer.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

83 lines
1.9 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 (
"io/ioutil"
"path/filepath"
"strings"
"time"
)
func NewFreezer(root string) *freezerController {
return &freezerController{
root: filepath.Join(root, string(Freezer)),
}
}
type freezerController struct {
root string
}
func (f *freezerController) Name() Name {
return Freezer
}
func (f *freezerController) Path(path string) string {
return filepath.Join(f.root, path)
}
func (f *freezerController) Freeze(path string) error {
return f.waitState(path, Frozen)
}
func (f *freezerController) Thaw(path string) error {
return f.waitState(path, Thawed)
}
func (f *freezerController) changeState(path string, state State) error {
return retryingWriteFile(
filepath.Join(f.root, path, "freezer.state"),
[]byte(strings.ToUpper(string(state))),
defaultFilePerm,
)
}
func (f *freezerController) state(path string) (State, error) {
current, err := ioutil.ReadFile(filepath.Join(f.root, path, "freezer.state"))
if err != nil {
return "", err
}
return State(strings.ToLower(strings.TrimSpace(string(current)))), nil
}
func (f *freezerController) waitState(path string, state State) error {
for {
if err := f.changeState(path, state); err != nil {
return err
}
current, err := f.state(path)
if err != nil {
return err
}
if current == state {
return nil
}
time.Sleep(1 * time.Millisecond)
}
}