1#!/bin/bash
2
3# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
4# Use of this source code is governed by a BSD-style license that can be
5# found in the LICENSE file.
6
7# This script creates a CPU set and binds the MySQL process to the
8# set. It restarts MySQL if specified in the option. This script needs
9# to be run with "sudo".
10
11set -e # Exit if any function returns a non-zero value.
12set -o nounset # Exit if any variable is used unset.
13
14MYSQL_PATH='/etc/init.d/mysql.server'
15MYSQL_PID_PATH='/var/lib/mysql/atlantis1.mtv.corp.google.com.pid'
16MYSQL_PROC_NAME='mysqld'
17
18# The directory where we mount the cpuset virutal file system to.
19MOUNT_DIR='/dev/cpuset'
20# The base cpuset directory for mysql.
21MYSQL_CPUSET='mysql'
22# CPUs in MySQL cpuset. E.g. 0-2,7,12-14.
23MYSQL_DEFAULT_CPUS=10-15
24
25
26# Display usage.
27function usage() {
28  echo -e "Usage: $0 [-c <CPUs>] [-p <PID>] [-r] [-d]\n"
29  echo -e "Create and bind the MySQL process to a specified CPU set.\n"
30  echo -e "Options:"
31  echo -e "  -c <CPUs>  Specify a list of CPUs to be used. E.g. 0-2,7,12-14"
32  echo -e "             (Default: $MYSQL_DEFAULT_CPUS)."
33  echo -e "  -d         Delete the CPU set. This option kills the current"
34  echo -e "             MySQL process and delete the CPU set. It does not"
35  echo -e "             restart MySQL nor create a new CPU set. (Default:"
36  echo -e "             disabled)."
37  echo -e "  -p <PID>   Bind <PID> to the cpuset (Default: the script searches"
38  echo -e "             for the MySQL PID automatically)."
39  echo -e "  -r         Restart MySQL (Default: disabled)."
40  echo -e "  -h         Display this usage information."
41  echo -e "\n"
42}
43
44function print_info() {
45  msg=$1
46  echo "INFO:  "$msg
47}
48
49function print_error() {
50  msg=$1
51  echo "ERROR: "$msg
52}
53
54# Run and print out the command if the silent flag is not set (the default).
55# Usage: run_cmd <cmd> [slient]
56function run_cmd() {
57  cmd=""
58  slient=0
59
60  if [ $# -gt 0 ]; then
61    cmd=$1
62  else
63    print_error "Empty command!"
64    return 1
65  fi
66
67  if [ $# -gt 1 ]; then
68    silent=$2
69  fi
70
71  if [ $slient -eq 0 ]; then
72    print_info "Running \"${1}\""
73  fi
74
75  # Print an error message if the command failed.
76  eval "$1" || { print_error "Failed to execute \"${cmd}\""; return 1; }
77}
78
79# Get the PID of the MySQL.
80function get_mysql_pid() {
81  local pid=""
82
83  if [ $# -gt 0 ] && [ ! -z "$1" ]; then
84    # Use user-provided PID.
85    pid=$1
86  elif [ ! -z ${MYSQL_PID_PATH} -a -f ${MYSQL_PID_PATH} ]; then
87    # Get PID from MySQL PID file if it is set.
88    print_info "Getting MySQL PID from ${MYSQL_PID_PATH}..."
89    pid=$(cat $MYSQL_PID_PATH) || \
90      { print_error "No MySQL process found."; return 1; }
91  else
92    # Get PID of process named mysqld.
93    print_info "Searching for MySQL PID..."
94    # Ignore the return code to print out an error message.
95    pid=$(pidof $MYSQL_PROC_NAME) || \
96      { print_error "No MySQL process found."; return 1; }
97  fi
98
99  # Test if the PID is an integer
100  if [[ $pid != [0-9]* ]]; then
101    print_error "No MySQL process found."
102    return 1
103  fi
104
105  # Check if the PID is a running process.
106  if [ ! -d "/proc/${pid}" ]; then
107    print_error "No running MySQL process is found."
108    return 1
109  fi
110
111  _RET="$pid"
112  print_info "MySQL PID is ${pid}."
113}
114
115# Mount the cpuset virtual file system.
116function mount_cpuset() {
117  if (mount | grep "on ${MOUNT_DIR} type" > /dev/null)
118  then
119    print_info "${MOUNT_DIR} already mounted."
120  else
121    print_info "Mounting cpuset to $MOUNT_DIR."
122    run_cmd "mkdir -p ${MOUNT_DIR}"
123    run_cmd "mount -t cpuset none ${MOUNT_DIR}"
124  fi
125}
126
127
128function clean_all() {
129  local delete_msg="No"
130  print_info "Will Delete existing CPU set..."
131  echo -ne "WARNING: This operation will kill all running "
132  echo "processes in the CPU set."
133  echo -ne "Are you sure you want to proceed "
134  echo -ne "(type \"yes\" or \"Yes\" to proceed)? "
135  read delete_msg
136
137  mount_cpuset
138
139  local proc_list=""
140  local proc=""
141
142  if [ "$delete_msg" = "yes" -o "$delete_msg" = "Yes" ]; then
143    if [ -d "${MOUNT_DIR}/${MYSQL_CPUSET}" ]; then
144      proc_list=$(cat ${MOUNT_DIR}/${MYSQL_CPUSET}/cgroup.procs)
145      for proc in $proc_list; do
146        run_cmd "kill -9 ${proc}"
147      done
148      # Remove the CPU set directory.
149      run_cmd "rmdir ${MOUNT_DIR}/${MYSQL_CPUSET}"
150      # Unmount the cpuset virtual file system.
151      run_cmd "umount ${MOUNT_DIR}"
152    else
153      print_info "The CPU set does not exist."
154      return 1
155    fi
156    print_info "Done!"
157  else
158    # User does not wish to continue.
159    print_info "Aborting program."
160  fi
161}
162
163
164function main() {
165
166  local MYSQL_CPUS=$MYSQL_DEFAULT_CPUS
167  local RESTART_MYSQL_FLAG=0
168  local DELETE_CPUSET_FLAG=0
169  local MYSQL_PID=""
170
171  # Parse command-line arguments.
172  while getopts ":c:dhp:r" opt; do
173    case $opt in
174      c)
175        MYSQL_CPUS=$OPTARG
176        ;;
177      d)
178        DELETE_CPUSET_FLAG=1
179        ;;
180      h)
181        usage
182        return 0
183        ;;
184      p)
185        MYSQL_PID=$OPTARG
186        ;;
187      r)
188        RESTART_MYSQL_FLAG=1
189        ;;
190      \?)
191        echo "Invalid option: -$OPTARG" >&2
192        usage
193        return 1
194        ;;
195      :)
196        echo "Option -$OPTARG requires an argument." >&2
197        usage
198        return 1
199        ;;
200    esac
201  done
202
203
204  # Clean up and exit if the flag is set.
205  if [ $DELETE_CPUSET_FLAG -eq 1 ]; then
206    clean_all
207    return 0
208  fi
209
210  # Restart MySQL.
211  if [ $RESTART_MYSQL_FLAG -eq 1 ]; then
212    print_info "Restarting MySQL..."
213    $MYSQL_PATH restart
214  fi
215
216
217  # Get PID of MySQL.
218  get_mysql_pid "$MYSQL_PID"
219  MYSQL_PID=$_RET
220
221  mount_cpuset
222
223  # Make directory for MySql.
224  print_info "Making a cpuset for MySQL..."
225  run_cmd "mkdir -p ${MOUNT_DIR}/${MYSQL_CPUSET}"
226
227  # Change working directory.
228  run_cmd "cd ${MOUNT_DIR}/${MYSQL_CPUSET}"
229
230  # Update the CPUs to use in the CPU set. Note that we use /bin/echo
231  # explicitly (instead of "echo") because it displays write errors.
232  print_info "Updating CPUs in the cpuset..."
233  run_cmd "bash -c \"/bin/echo ${MYSQL_CPUS} > cpus\""
234
235  # Attach/Rebind MySQL process to the cpuset. Note that this command
236  # can only attach one PID at a time. This needs to be run every time
237  # after the CPU set is modified.
238  print_info "Bind MySQL process to the cpuset..."
239  run_cmd "bash -c \"/bin/echo ${MYSQL_PID} > tasks\""
240
241  print_info "Done!"
242}
243
244main "$@"
245