cubefs

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// Copyright 2018 The CubeFS Authors.
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//
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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
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// implied. See the License for the specific language governing
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// permissions and limitations under the License.
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package util
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import (
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	"bufio"
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	"fmt"
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	"os"
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	"strconv"
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	"strings"
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)
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const (
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	MEMINFO = "/proc/meminfo"
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	PRO_MEM = "/proc/%d/status"
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)
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// GetMemInfo returns the memory information.
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func GetMemInfo() (total, used uint64, err error) {
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	fp, err := os.Open(MEMINFO)
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	if err != nil {
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		return
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	}
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	// TODO Unhandled errors
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	defer fp.Close()
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	var (
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		val    uint64
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		free   uint64
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		buffer uint64
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		cached uint64
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	)
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	scan := bufio.NewScanner(fp)
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	for scan.Scan() {
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		line := scan.Text()
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		fields := strings.Split(line, ":")
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		if len(fields) != 2 {
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			continue
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		}
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		key := fields[0]
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		value := strings.TrimSpace(fields[1])
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		value = strings.Replace(value, " kB", "", -1)
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		val, err = strconv.ParseUint(value, 10, 64)
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		if err != nil {
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			return
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		}
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		switch key {
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		case "MemTotal":
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			total = val * KB
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		case "MemFree":
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			free = val * KB
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		case "Buffers":
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			buffer = val * KB
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		case "Cached":
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			cached = val * KB
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		default:
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			// do nothing
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		}
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	}
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	used = total - free - buffer - cached
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	return
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}
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func GetProcessMemory(pid int) (used uint64, err error) {
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	proFileName := fmt.Sprintf(PRO_MEM, pid)
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	fp, err := os.Open(proFileName)
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	if err != nil {
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		return
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	}
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	defer fp.Close()
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	scan := bufio.NewScanner(fp)
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	for scan.Scan() {
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		line := scan.Text()
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		fields := strings.Split(line, ":")
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		key := fields[0]
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		if key != "VmRSS" {
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			continue
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		}
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		value := strings.TrimSpace(fields[1])
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		value = strings.Replace(value, " kB", "", -1)
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		used, err = strconv.ParseUint(value, 10, 64)
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		if err != nil {
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			return
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		}
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		used = used * KB
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		break
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	}
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	return
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}
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