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="$1"
  28
  29         grep -sq ^"$zram_dev " /proc/swaps && {
  30                 logger -s -t zram_applicable -p daemon.notice "[OK] '$zram_dev' already active"
  31                 return 1
  32         }
  33
  34         [ -e "$zram_dev" ] || {
  35                 logger -s -t zram_applicable -p daemon.crit "[ERROR] device '$zram_dev' not found"
  36                 return 1
  37         }
  38
  39         which mkswap >/dev/null || {
  40                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'mkswap' not installed"
  41                 return 1
  42         }
  43
  44         which swapon >/dev/null || {
  45                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'swapon' not installed"
  46                 return 1
  47         }
  48
  49         which swapoff >/dev/null || {
  50                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'swapoff' not installed"
  51                 return 1
  52         }
  53 }
  54
  55 zram_dev()
  56 {
  57         local core="$1"
  58
  59         echo "/dev/zram${core:-0}"
  60 }
  61
  62 zram_reset()
  63 {
  64         local dev="$1"
  65         local message="$2"
  66         local proc_entry="/sys/block/$( basename "$dev" )/reset"
  67
  68         logger -s -t zram_reset -p daemon.debug "$message via $proc_entry"
  69         echo "1" >"$proc_entry"
  70 }
  71
  72 list_cpu_idx()
  73 {
  74         # Offset by 1 if /dev/zram0 is in use by /tmp
  75         if [ "$(mount | grep /dev/zram0)" ]; then
  76                 local line i=1
  77                 # Hot-add new ZRAM device (if necessary)
  78                 if [ ! -b /dev/zram1 ]; then
  79                         cat /sys/class/zram-control/hot_add
  80                 fi
  81         else
  82                 local line i=0
  83         fi
  84
  85         while read line; do {
  86                 case "$line" in
  87                         [Pp]rocessor*)
  88                                 echo $i
  89                                 i=$(( $i + 1 ))
  90                         ;;
  91                 esac
  92         } done <"/proc/cpuinfo"
  93 }
  94
  95 start()
  96 {
  97         # http://shmilyxbq-compcache.googlecode.com/hg/README
  98         # if >1 cpu_core, reinit kmodule with e.g. num_devices=4
  99
 100         local zram_size="$( zram_size )"
 101         local zram_dev core
 102
 103         for core in $( list_cpu_idx ); do {
 104                 zram_dev="$( zram_dev "$core" )"
 105                 zram_applicable "$zram_dev" || return 1
 106
 107                 logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MegaBytes)"
 108
 109                 zram_reset "$zram_dev" "enforcing defaults"
 110                 echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename $zram_dev )/disksize"
 111                 mkswap "$zram_dev"
 112                 swapon "$zram_dev"
 113         } done
 114 }
 115
 116 stop()
 117 {
 118         local zram_dev proc_entry
 119
 120         for core in $( list_cpu_idx ); do {
 121                 zram_dev="$( zram_dev "$core" )"
 122                 proc_entry="/sys/block/$( basename "$zram_dev" )/reset"
 123
 124                 grep -sq ^"$zram_dev " /proc/swaps && {
 125                         logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
 126                         swapoff "$zram_dev"
 127                 }
 128
 129                 zram_reset "$zram_dev" "claiming memory back"
 130         } done
 131 }
 132