gotosocial/vendor/github.com/docker/go-units/ulimit.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

123 lines
3.1 KiB
Go

package units
import (
"fmt"
"strconv"
"strings"
)
// Ulimit is a human friendly version of Rlimit.
type Ulimit struct {
Name string
Hard int64
Soft int64
}
// Rlimit specifies the resource limits, such as max open files.
type Rlimit struct {
Type int `json:"type,omitempty"`
Hard uint64 `json:"hard,omitempty"`
Soft uint64 `json:"soft,omitempty"`
}
const (
// magic numbers for making the syscall
// some of these are defined in the syscall package, but not all.
// Also since Windows client doesn't get access to the syscall package, need to
// define these here
rlimitAs = 9
rlimitCore = 4
rlimitCPU = 0
rlimitData = 2
rlimitFsize = 1
rlimitLocks = 10
rlimitMemlock = 8
rlimitMsgqueue = 12
rlimitNice = 13
rlimitNofile = 7
rlimitNproc = 6
rlimitRss = 5
rlimitRtprio = 14
rlimitRttime = 15
rlimitSigpending = 11
rlimitStack = 3
)
var ulimitNameMapping = map[string]int{
//"as": rlimitAs, // Disabled since this doesn't seem usable with the way Docker inits a container.
"core": rlimitCore,
"cpu": rlimitCPU,
"data": rlimitData,
"fsize": rlimitFsize,
"locks": rlimitLocks,
"memlock": rlimitMemlock,
"msgqueue": rlimitMsgqueue,
"nice": rlimitNice,
"nofile": rlimitNofile,
"nproc": rlimitNproc,
"rss": rlimitRss,
"rtprio": rlimitRtprio,
"rttime": rlimitRttime,
"sigpending": rlimitSigpending,
"stack": rlimitStack,
}
// ParseUlimit parses and returns a Ulimit from the specified string.
func ParseUlimit(val string) (*Ulimit, error) {
parts := strings.SplitN(val, "=", 2)
if len(parts) != 2 {
return nil, fmt.Errorf("invalid ulimit argument: %s", val)
}
if _, exists := ulimitNameMapping[parts[0]]; !exists {
return nil, fmt.Errorf("invalid ulimit type: %s", parts[0])
}
var (
soft int64
hard = &soft // default to soft in case no hard was set
temp int64
err error
)
switch limitVals := strings.Split(parts[1], ":"); len(limitVals) {
case 2:
temp, err = strconv.ParseInt(limitVals[1], 10, 64)
if err != nil {
return nil, err
}
hard = &temp
fallthrough
case 1:
soft, err = strconv.ParseInt(limitVals[0], 10, 64)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("too many limit value arguments - %s, can only have up to two, `soft[:hard]`", parts[1])
}
if *hard != -1 {
if soft == -1 {
return nil, fmt.Errorf("ulimit soft limit must be less than or equal to hard limit: soft: -1 (unlimited), hard: %d", *hard)
}
if soft > *hard {
return nil, fmt.Errorf("ulimit soft limit must be less than or equal to hard limit: %d > %d", soft, *hard)
}
}
return &Ulimit{Name: parts[0], Soft: soft, Hard: *hard}, nil
}
// GetRlimit returns the RLimit corresponding to Ulimit.
func (u *Ulimit) GetRlimit() (*Rlimit, error) {
t, exists := ulimitNameMapping[u.Name]
if !exists {
return nil, fmt.Errorf("invalid ulimit name %s", u.Name)
}
return &Rlimit{Type: t, Soft: uint64(u.Soft), Hard: uint64(u.Hard)}, nil
}
func (u *Ulimit) String() string {
return fmt.Sprintf("%s=%d:%d", u.Name, u.Soft, u.Hard)
}