cubefs

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// Copyright 2017 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package procfs
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import (
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	"bufio"
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	"fmt"
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	"io"
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	"os"
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	"strconv"
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	"strings"
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)
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// A BuddyInfo is the details parsed from /proc/buddyinfo.
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// The data is comprised of an array of free fragments of each size.
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// The sizes are 2^n*PAGE_SIZE, where n is the array index.
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type BuddyInfo struct {
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	Node  string
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	Zone  string
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	Sizes []float64
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}
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// BuddyInfo reads the buddyinfo statistics from the specified `proc` filesystem.
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func (fs FS) BuddyInfo() ([]BuddyInfo, error) {
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	file, err := os.Open(fs.proc.Path("buddyinfo"))
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	if err != nil {
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		return nil, err
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	}
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	defer file.Close()
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	return parseBuddyInfo(file)
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}
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func parseBuddyInfo(r io.Reader) ([]BuddyInfo, error) {
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	var (
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		buddyInfo   = []BuddyInfo{}
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		scanner     = bufio.NewScanner(r)
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		bucketCount = -1
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	)
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	for scanner.Scan() {
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		var err error
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		line := scanner.Text()
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		parts := strings.Fields(line)
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		if len(parts) < 4 {
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			return nil, fmt.Errorf("invalid number of fields when parsing buddyinfo")
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		}
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		node := strings.TrimRight(parts[1], ",")
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		zone := strings.TrimRight(parts[3], ",")
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		arraySize := len(parts[4:])
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		if bucketCount == -1 {
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			bucketCount = arraySize
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		} else {
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			if bucketCount != arraySize {
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				return nil, fmt.Errorf("mismatch in number of buddyinfo buckets, previous count %d, new count %d", bucketCount, arraySize)
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			}
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		}
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		sizes := make([]float64, arraySize)
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		for i := 0; i < arraySize; i++ {
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			sizes[i], err = strconv.ParseFloat(parts[i+4], 64)
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			if err != nil {
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				return nil, fmt.Errorf("invalid value in buddyinfo: %w", err)
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			}
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		}
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		buddyInfo = append(buddyInfo, BuddyInfo{node, zone, sizes})
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	}
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	return buddyInfo, scanner.Err()
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}
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