centos/etc/init.d/zramswap

   1 #!/bin/bash
   2
   3 # chkconfig: 345 20 80
   4 # description: Linux zramswap setup
   5
   6 NUM_CPUS=$(nproc)
   7 [ "$NUM_CPUS" != 0 ] || NUM_CPUS=1
   8 NUM_DEVS=$NUM_CPUS      # kernel version <= 3.15
   9 FACTOR=50 # percentage
  10 TOTALRAM=$(grep MemTotal /proc/meminfo | awk ' { print $2 } ')
  11 DISK_SIZE=$(($TOTALRAM/$NUM_CPUS*$FACTOR/100*1024))
  12
  13 # show supported compression algorithms: `cat /sys/block/zram*/comp_algorithm`
  14 # select your compression algorithm, lzo is the default
  15 # speed: lz4 > zstd > lzo
  16 # compression: zstd > lzo > lz4
  17 COMP_ALGORITHMS=lzo
  18
  19 #Defaults for vm.overcommit_memory, vm.page-cluster, vm.swappiness
  20 OVERCOMMIT_MEMORY=0
  21 PAGE_CLUSTER=3
  22 SWAPPINESS=100
  23
  24
  25 start() {
  26   [ ! -e /sys/module/zram ] && modprobe zram num_devices=$NUM_DEVS || modprobe -r zram && modprobe zram num_devices=$NUM_DEVS
  27   for i in /sys/block/zram*; do
  28     /usr/bin/echo $COMP_ALGORITHMS > ${i}/comp_algorithm;
  29     /usr/bin/echo $DISK_SIZE > ${i}/disksize;
  30   done
  31
  32   for i in /dev/zram*; do
  33     /usr/sbin/mkswap ${i};
  34     /usr/sbin/swapon -d -p100 ${i};
  35   done
  36
  37   echo 1 > /proc/sys/vm/overcommit_memory
  38   echo 0 > /proc/sys/vm/page-cluster
  39   echo 100 > /proc/sys/vm/swappiness
  40 }
  41
  42 stop() {
  43   [ ! -e /sys/module/zram ] && exit 0
  44
  45   echo $OVERCOMMIT_MEMORY > /proc/sys/vm/overcommit_memory
  46   echo $PAGE_CLUSTER > /proc/sys/vm/page-cluster
  47   echo $SWAPPINESS > /proc/sys/vm/swappiness
  48
  49   for i in /dev/zram*; do
  50     /usr/sbin/swapoff ${i};
  51   done
  52
  53   for i in /sys/block/zram*; do
  54     /usr/bin/echo 1 > ${i}/reset;
  55   done
  56   [ -e /sys/module/zram ] && modprobe -r zram
  57 }
  58
  59 case $1 in
  60   (start|stop) "$1" ;;
  61 esac