package/system/zram-swap/files/zram.init

   1 #!/bin/sh /etc/rc.common
   2
   3 START=15
   4
   5 ram_size()
   6 {
   7         local line
   8
   9         while read line; do case "$line" in MemTotal:*) set $line; echo "$2"; break ;; esac; done </proc/meminfo
  10 }
  11
  12 zram_size()     # in megabytes
  13 {
  14         local zram_size="$( uci -q get system.@system[0].zram_size_mb )"
  15         local ram_size="$( ram_size )"
  16
  17         if [ -z "$zram_size" ]; then
  18                 # e.g. 6mb for 16mb-routers or 61mb for 128mb-routers
  19                 echo $(( ram_size / 2048 ))
  20         else
  21                 echo "$zram_size"
  22         fi
  23 }
  24
  25 zram_applicable()
  26 {
  27         local zram_dev="$1"
  28
  29         [ -e "$zram_dev" ] || {
  30                 logger -s -t zram_applicable -p daemon.crit "[ERROR] device '$zram_dev' not found"
  31                 return 1
  32         }
  33
  34         which mkswap >/dev/null || {
  35                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'mkswap' not installed"
  36                 return 1
  37         }
  38
  39         which swapon >/dev/null || {
  40                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'swapon' not installed"
  41                 return 1
  42         }
  43
  44         which swapoff >/dev/null || {
  45                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'swapoff' not installed"
  46                 return 1
  47         }
  48 }
  49
  50 zram_dev()
  51 {
  52         local idx="$1"
  53         echo "/dev/zram${idx:-0}"
  54 }
  55
  56 zram_reset()
  57 {
  58         local dev="$1"
  59         local message="$2"
  60         local proc_entry="/sys/block/$( basename "$dev" )/reset"
  61
  62         logger -s -t zram_reset -p daemon.debug "$message via $proc_entry"
  63         echo "1" >"$proc_entry"
  64 }
  65
  66 zram_getdev()
  67 {
  68         #get unallocated zram dev
  69         local zdev=$( zram_dev )
  70
  71         if [ "$(mount | grep $zdev)" ]; then
  72                 local idx=`cat /sys/class/zram-control/hot_add`
  73                 zdev="$( zram_dev $idx )"
  74         fi
  75
  76         echo $zdev
  77 }
  78
  79 zram_comp_algo()
  80 {
  81         local dev="$1"
  82         local zram_comp_algo="$( uci -q get system.@system[0].zram_comp_algo )"
  83
  84         if [ -z "$zram_comp_algo" ] || [ ! -e /sys/block/$( basename $dev )/comp_algorithm ]; then
  85                 return 0
  86         fi
  87
  88         if [ `grep -c "$zram_comp_algo" /sys/block/$( basename $dev )/comp_algorithm` -ne 0 ]; then
  89                 logger -s -t zram_comp_algo -p daemon.debug "Set compression algorithm '$zram_comp_algo' for zram '$dev'"
  90                 echo $zram_comp_algo > "/sys/block/$( basename $dev )/comp_algorithm"
  91         else
  92                 logger -s -t zram_comp_algo -p daemon.debug "Compression algorithm '$zram_comp_algo' is not supported for '$dev'"
  93         fi
  94 }
  95
  96 start()
  97 {
  98         local zram_size="$( zram_size )"
  99         local zram_dev
 100
 101         if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
 102                 logger -s -t zram_start -p daemon.notice "[OK] zram swap is already mounted"
 103                 return 1
 104         fi
 105
 106         zram_dev="$( zram_getdev )"
 107         zram_applicable "$zram_dev" || return 1
 108
 109         logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MegaBytes)"
 110
 111         zram_reset "$zram_dev" "enforcing defaults"
 112         zram_comp_algo "$zram_dev"
 113         echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename "$zram_dev" )/disksize"
 114         mkswap "$zram_dev"
 115         swapon "$zram_dev"
 116 }
 117
 118 stop()
 119 {
 120         local zram_dev
 121
 122         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 123                 logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
 124                 swapoff "$zram_dev" && zram_reset "$zram_dev" "claiming memory back"
 125                 local dev_index="$( echo $zram_dev | grep -o "[0-9]*$" )"
 126                 if [ $dev_index -ne 0 ]; then
 127                         logger -s -t zram_stop -p daemon.debug "removing zram $zram_dev"
 128                         echo $dev_index > /sys/class/zram-control/hot_remove
 129                 fi
 130         } done
 131 }
 132