go1.16 (#14783)

vendor/github.com/prometheus/procfs/slab.go

@@ -0,0 +1,151 @@
+// Copyright 2020 The Prometheus 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 procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+var (
+	slabSpace  = regexp.MustCompile(`\s+`)
+	slabVer    = regexp.MustCompile(`slabinfo -`)
+	slabHeader = regexp.MustCompile(`# name`)
+)
+
+// Slab represents a slab pool in the kernel.
+type Slab struct {
+	Name         string
+	ObjActive    int64
+	ObjNum       int64
+	ObjSize      int64
+	ObjPerSlab   int64
+	PagesPerSlab int64
+	// tunables
+	Limit        int64
+	Batch        int64
+	SharedFactor int64
+	SlabActive   int64
+	SlabNum      int64
+	SharedAvail  int64
+}
+
+// SlabInfo represents info for all slabs.
+type SlabInfo struct {
+	Slabs []*Slab
+}
+
+func shouldParseSlab(line string) bool {
+	if slabVer.MatchString(line) {
+		return false
+	}
+	if slabHeader.MatchString(line) {
+		return false
+	}
+	return true
+}
+
+// parseV21SlabEntry is used to parse a line from /proc/slabinfo version 2.1.
+func parseV21SlabEntry(line string) (*Slab, error) {
+	// First cleanup whitespace.
+	l := slabSpace.ReplaceAllString(line, " ")
+	s := strings.Split(l, " ")
+	if len(s) != 16 {
+		return nil, fmt.Errorf("unable to parse: %q", line)
+	}
+	var err error
+	i := &Slab{Name: s[0]}
+	i.ObjActive, err = strconv.ParseInt(s[1], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.ObjNum, err = strconv.ParseInt(s[2], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.ObjSize, err = strconv.ParseInt(s[3], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.ObjPerSlab, err = strconv.ParseInt(s[4], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.PagesPerSlab, err = strconv.ParseInt(s[5], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.Limit, err = strconv.ParseInt(s[8], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.Batch, err = strconv.ParseInt(s[9], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.SharedFactor, err = strconv.ParseInt(s[10], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.SlabActive, err = strconv.ParseInt(s[13], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.SlabNum, err = strconv.ParseInt(s[14], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	i.SharedAvail, err = strconv.ParseInt(s[15], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	return i, nil
+}
+
+// parseSlabInfo21 is used to parse a slabinfo 2.1 file.
+func parseSlabInfo21(r *bytes.Reader) (SlabInfo, error) {
+	scanner := bufio.NewScanner(r)
+	s := SlabInfo{Slabs: []*Slab{}}
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !shouldParseSlab(line) {
+			continue
+		}
+		slab, err := parseV21SlabEntry(line)
+		if err != nil {
+			return s, err
+		}
+		s.Slabs = append(s.Slabs, slab)
+	}
+	return s, nil
+}
+
+// SlabInfo reads data from /proc/slabinfo
+func (fs FS) SlabInfo() (SlabInfo, error) {
+	// TODO: Consider passing options to allow for parsing different
+	// slabinfo versions. However, slabinfo 2.1 has been stable since
+	// kernel 2.6.10 and later.
+	data, err := util.ReadFileNoStat(fs.proc.Path("slabinfo"))
+	if err != nil {
+		return SlabInfo{}, err
+	}
+
+	return parseSlabInfo21(bytes.NewReader(data))
+}