gotosocial/vendor/github.com/KimMachineGun/automemlimit/memlimit/cgroups.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

63 lines
1.3 KiB
Go

//go:build linux
// +build linux
package memlimit
import (
"github.com/containerd/cgroups"
v2 "github.com/containerd/cgroups/v2"
)
const (
cgroupMountPoint = "/sys/fs/cgroup"
)
// FromCgroup returns the memory limit based on the cgroups version on this system.
func FromCgroup() (uint64, error) {
switch cgroups.Mode() {
case cgroups.Legacy:
return FromCgroupV1()
case cgroups.Hybrid, cgroups.Unified:
return FromCgroupV2()
}
return 0, ErrNoCgroup
}
// FromCgroupV1 returns the memory limit from the cgroup v1.
func FromCgroupV1() (uint64, error) {
cg, err := cgroups.Load(cgroups.SingleSubsystem(cgroups.V1, cgroups.Memory), cgroups.RootPath)
if err != nil {
return 0, err
}
metrics, err := cg.Stat(cgroups.IgnoreNotExist)
if err != nil {
return 0, err
} else if metrics.Memory == nil {
return 0, ErrNoLimit
}
return metrics.Memory.HierarchicalMemoryLimit, nil
}
// FromCgroupV2 returns the memory limit from the cgroup v2.
func FromCgroupV2() (uint64, error) {
path, err := v2.NestedGroupPath("")
if err != nil {
return 0, err
}
m, err := v2.LoadManager(cgroupMountPoint, path)
if err != nil {
return 0, err
}
stats, err := m.Stat()
if err != nil {
return 0, err
} else if stats.Memory == nil {
return 0, ErrNoLimit
}
return stats.Memory.UsageLimit, nil
}