gotosocial/vendor/github.com/cilium/ebpf/syscalls.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

491 lines
12 KiB
Go

package ebpf
import (
"errors"
"fmt"
"unsafe"
"github.com/cilium/ebpf/internal"
"github.com/cilium/ebpf/internal/btf"
"github.com/cilium/ebpf/internal/unix"
)
// Generic errors returned by BPF syscalls.
var ErrNotExist = errors.New("requested object does not exist")
// bpfObjName is a null-terminated string made up of
// 'A-Za-z0-9_' characters.
type bpfObjName [unix.BPF_OBJ_NAME_LEN]byte
// newBPFObjName truncates the result if it is too long.
func newBPFObjName(name string) bpfObjName {
var result bpfObjName
copy(result[:unix.BPF_OBJ_NAME_LEN-1], name)
return result
}
// invalidBPFObjNameChar returns true if char may not appear in
// a BPF object name.
func invalidBPFObjNameChar(char rune) bool {
dotAllowed := objNameAllowsDot() == nil
switch {
case char >= 'A' && char <= 'Z':
return false
case char >= 'a' && char <= 'z':
return false
case char >= '0' && char <= '9':
return false
case dotAllowed && char == '.':
return false
case char == '_':
return false
default:
return true
}
}
type bpfMapCreateAttr struct {
mapType MapType
keySize uint32
valueSize uint32
maxEntries uint32
flags uint32
innerMapFd uint32 // since 4.12 56f668dfe00d
numaNode uint32 // since 4.14 96eabe7a40aa
mapName bpfObjName // since 4.15 ad5b177bd73f
mapIfIndex uint32
btfFd uint32
btfKeyTypeID btf.TypeID
btfValueTypeID btf.TypeID
}
type bpfMapOpAttr struct {
mapFd uint32
padding uint32
key internal.Pointer
value internal.Pointer
flags uint64
}
type bpfBatchMapOpAttr struct {
inBatch internal.Pointer
outBatch internal.Pointer
keys internal.Pointer
values internal.Pointer
count uint32
mapFd uint32
elemFlags uint64
flags uint64
}
type bpfMapInfo struct {
map_type uint32 // since 4.12 1e2709769086
id uint32
key_size uint32
value_size uint32
max_entries uint32
map_flags uint32
name bpfObjName // since 4.15 ad5b177bd73f
ifindex uint32 // since 4.16 52775b33bb50
btf_vmlinux_value_type_id uint32 // since 5.6 85d33df357b6
netns_dev uint64 // since 4.16 52775b33bb50
netns_ino uint64
btf_id uint32 // since 4.18 78958fca7ead
btf_key_type_id uint32 // since 4.18 9b2cf328b2ec
btf_value_type_id uint32
}
type bpfProgLoadAttr struct {
progType ProgramType
insCount uint32
instructions internal.Pointer
license internal.Pointer
logLevel uint32
logSize uint32
logBuf internal.Pointer
kernelVersion uint32 // since 4.1 2541517c32be
progFlags uint32 // since 4.11 e07b98d9bffe
progName bpfObjName // since 4.15 067cae47771c
progIfIndex uint32 // since 4.15 1f6f4cb7ba21
expectedAttachType AttachType // since 4.17 5e43f899b03a
progBTFFd uint32
funcInfoRecSize uint32
funcInfo internal.Pointer
funcInfoCnt uint32
lineInfoRecSize uint32
lineInfo internal.Pointer
lineInfoCnt uint32
attachBTFID btf.TypeID
attachProgFd uint32
}
type bpfProgInfo struct {
prog_type uint32
id uint32
tag [unix.BPF_TAG_SIZE]byte
jited_prog_len uint32
xlated_prog_len uint32
jited_prog_insns internal.Pointer
xlated_prog_insns internal.Pointer
load_time uint64 // since 4.15 cb4d2b3f03d8
created_by_uid uint32
nr_map_ids uint32
map_ids internal.Pointer
name bpfObjName // since 4.15 067cae47771c
ifindex uint32
gpl_compatible uint32
netns_dev uint64
netns_ino uint64
nr_jited_ksyms uint32
nr_jited_func_lens uint32
jited_ksyms internal.Pointer
jited_func_lens internal.Pointer
btf_id uint32
func_info_rec_size uint32
func_info internal.Pointer
nr_func_info uint32
nr_line_info uint32
line_info internal.Pointer
jited_line_info internal.Pointer
nr_jited_line_info uint32
line_info_rec_size uint32
jited_line_info_rec_size uint32
nr_prog_tags uint32
prog_tags internal.Pointer
run_time_ns uint64
run_cnt uint64
}
type bpfProgTestRunAttr struct {
fd uint32
retval uint32
dataSizeIn uint32
dataSizeOut uint32
dataIn internal.Pointer
dataOut internal.Pointer
repeat uint32
duration uint32
}
type bpfGetFDByIDAttr struct {
id uint32
next uint32
}
type bpfMapFreezeAttr struct {
mapFd uint32
}
type bpfObjGetNextIDAttr struct {
startID uint32
nextID uint32
openFlags uint32
}
func bpfProgLoad(attr *bpfProgLoadAttr) (*internal.FD, error) {
for {
fd, err := internal.BPF(internal.BPF_PROG_LOAD, unsafe.Pointer(attr), unsafe.Sizeof(*attr))
// As of ~4.20 the verifier can be interrupted by a signal,
// and returns EAGAIN in that case.
if err == unix.EAGAIN {
continue
}
if err != nil {
return nil, err
}
return internal.NewFD(uint32(fd)), nil
}
}
func bpfProgTestRun(attr *bpfProgTestRunAttr) error {
_, err := internal.BPF(internal.BPF_PROG_TEST_RUN, unsafe.Pointer(attr), unsafe.Sizeof(*attr))
return err
}
func bpfMapCreate(attr *bpfMapCreateAttr) (*internal.FD, error) {
fd, err := internal.BPF(internal.BPF_MAP_CREATE, unsafe.Pointer(attr), unsafe.Sizeof(*attr))
if err != nil {
return nil, err
}
return internal.NewFD(uint32(fd)), nil
}
var haveNestedMaps = internal.FeatureTest("nested maps", "4.12", func() error {
_, err := bpfMapCreate(&bpfMapCreateAttr{
mapType: ArrayOfMaps,
keySize: 4,
valueSize: 4,
maxEntries: 1,
// Invalid file descriptor.
innerMapFd: ^uint32(0),
})
if errors.Is(err, unix.EINVAL) {
return internal.ErrNotSupported
}
if errors.Is(err, unix.EBADF) {
return nil
}
return err
})
var haveMapMutabilityModifiers = internal.FeatureTest("read- and write-only maps", "5.2", func() error {
// This checks BPF_F_RDONLY_PROG and BPF_F_WRONLY_PROG. Since
// BPF_MAP_FREEZE appeared in 5.2 as well we don't do a separate check.
m, err := bpfMapCreate(&bpfMapCreateAttr{
mapType: Array,
keySize: 4,
valueSize: 4,
maxEntries: 1,
flags: unix.BPF_F_RDONLY_PROG,
})
if err != nil {
return internal.ErrNotSupported
}
_ = m.Close()
return nil
})
func bpfMapLookupElem(m *internal.FD, key, valueOut internal.Pointer) error {
fd, err := m.Value()
if err != nil {
return err
}
attr := bpfMapOpAttr{
mapFd: fd,
key: key,
value: valueOut,
}
_, err = internal.BPF(internal.BPF_MAP_LOOKUP_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return wrapMapError(err)
}
func bpfMapLookupAndDelete(m *internal.FD, key, valueOut internal.Pointer) error {
fd, err := m.Value()
if err != nil {
return err
}
attr := bpfMapOpAttr{
mapFd: fd,
key: key,
value: valueOut,
}
_, err = internal.BPF(internal.BPF_MAP_LOOKUP_AND_DELETE_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return wrapMapError(err)
}
func bpfMapUpdateElem(m *internal.FD, key, valueOut internal.Pointer, flags uint64) error {
fd, err := m.Value()
if err != nil {
return err
}
attr := bpfMapOpAttr{
mapFd: fd,
key: key,
value: valueOut,
flags: flags,
}
_, err = internal.BPF(internal.BPF_MAP_UPDATE_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return wrapMapError(err)
}
func bpfMapDeleteElem(m *internal.FD, key internal.Pointer) error {
fd, err := m.Value()
if err != nil {
return err
}
attr := bpfMapOpAttr{
mapFd: fd,
key: key,
}
_, err = internal.BPF(internal.BPF_MAP_DELETE_ELEM, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return wrapMapError(err)
}
func bpfMapGetNextKey(m *internal.FD, key, nextKeyOut internal.Pointer) error {
fd, err := m.Value()
if err != nil {
return err
}
attr := bpfMapOpAttr{
mapFd: fd,
key: key,
value: nextKeyOut,
}
_, err = internal.BPF(internal.BPF_MAP_GET_NEXT_KEY, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return wrapMapError(err)
}
func objGetNextID(cmd internal.BPFCmd, start uint32) (uint32, error) {
attr := bpfObjGetNextIDAttr{
startID: start,
}
_, err := internal.BPF(cmd, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return attr.nextID, wrapObjError(err)
}
func bpfMapBatch(cmd internal.BPFCmd, m *internal.FD, inBatch, outBatch, keys, values internal.Pointer, count uint32, opts *BatchOptions) (uint32, error) {
fd, err := m.Value()
if err != nil {
return 0, err
}
attr := bpfBatchMapOpAttr{
inBatch: inBatch,
outBatch: outBatch,
keys: keys,
values: values,
count: count,
mapFd: fd,
}
if opts != nil {
attr.elemFlags = opts.ElemFlags
attr.flags = opts.Flags
}
_, err = internal.BPF(cmd, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
// always return count even on an error, as things like update might partially be fulfilled.
return attr.count, wrapMapError(err)
}
func wrapObjError(err error) error {
if err == nil {
return nil
}
if errors.Is(err, unix.ENOENT) {
return fmt.Errorf("%w", ErrNotExist)
}
return errors.New(err.Error())
}
func wrapMapError(err error) error {
if err == nil {
return nil
}
if errors.Is(err, unix.ENOENT) {
return ErrKeyNotExist
}
if errors.Is(err, unix.EEXIST) {
return ErrKeyExist
}
if errors.Is(err, unix.ENOTSUPP) {
return ErrNotSupported
}
return errors.New(err.Error())
}
func bpfMapFreeze(m *internal.FD) error {
fd, err := m.Value()
if err != nil {
return err
}
attr := bpfMapFreezeAttr{
mapFd: fd,
}
_, err = internal.BPF(internal.BPF_MAP_FREEZE, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return err
}
func bpfGetProgInfoByFD(fd *internal.FD) (*bpfProgInfo, error) {
var info bpfProgInfo
if err := internal.BPFObjGetInfoByFD(fd, unsafe.Pointer(&info), unsafe.Sizeof(info)); err != nil {
return nil, fmt.Errorf("can't get program info: %w", err)
}
return &info, nil
}
func bpfGetMapInfoByFD(fd *internal.FD) (*bpfMapInfo, error) {
var info bpfMapInfo
err := internal.BPFObjGetInfoByFD(fd, unsafe.Pointer(&info), unsafe.Sizeof(info))
if err != nil {
return nil, fmt.Errorf("can't get map info: %w", err)
}
return &info, nil
}
var haveObjName = internal.FeatureTest("object names", "4.15", func() error {
attr := bpfMapCreateAttr{
mapType: Array,
keySize: 4,
valueSize: 4,
maxEntries: 1,
mapName: newBPFObjName("feature_test"),
}
fd, err := bpfMapCreate(&attr)
if err != nil {
return internal.ErrNotSupported
}
_ = fd.Close()
return nil
})
var objNameAllowsDot = internal.FeatureTest("dot in object names", "5.2", func() error {
if err := haveObjName(); err != nil {
return err
}
attr := bpfMapCreateAttr{
mapType: Array,
keySize: 4,
valueSize: 4,
maxEntries: 1,
mapName: newBPFObjName(".test"),
}
fd, err := bpfMapCreate(&attr)
if err != nil {
return internal.ErrNotSupported
}
_ = fd.Close()
return nil
})
var haveBatchAPI = internal.FeatureTest("map batch api", "5.6", func() error {
var maxEntries uint32 = 2
attr := bpfMapCreateAttr{
mapType: Hash,
keySize: 4,
valueSize: 4,
maxEntries: maxEntries,
}
fd, err := bpfMapCreate(&attr)
if err != nil {
return internal.ErrNotSupported
}
defer fd.Close()
keys := []uint32{1, 2}
values := []uint32{3, 4}
kp, _ := marshalPtr(keys, 8)
vp, _ := marshalPtr(values, 8)
nilPtr := internal.NewPointer(nil)
_, err = bpfMapBatch(internal.BPF_MAP_UPDATE_BATCH, fd, nilPtr, nilPtr, kp, vp, maxEntries, nil)
if err != nil {
return internal.ErrNotSupported
}
return nil
})
func bpfObjGetFDByID(cmd internal.BPFCmd, id uint32) (*internal.FD, error) {
attr := bpfGetFDByIDAttr{
id: id,
}
ptr, err := internal.BPF(cmd, unsafe.Pointer(&attr), unsafe.Sizeof(attr))
return internal.NewFD(uint32(ptr)), wrapObjError(err)
}