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 zram_comp_streams()
  97 {
  98         local dev="$1"
  99         local logical_cpus=$( grep -ci "^processor" /proc/cpuinfo )
 100         [ $logical_cpus -gt 1 ] || return 1
 101         local zram_comp_streams="$( uci -q get system.@system[0].zram_comp_streams )"
 102         [ -n "$zram_comp_streams" ] && [ "$zram_comp_streams" -le "$logical_cpus" ] || zram_comp_streams=$logical_cpus
 103         if [ -e /sys/block/$( basename $dev )/max_comp_streams ]; then
 104                 logger -s -t zram_comp_streams -p daemon.debug "Set max compression streams to '$zram_comp_streams' for zram '$dev'"
 105                 echo $zram_comp_streams > /sys/block/$( basename $dev )/max_comp_streams
 106         fi
 107 }
 108
 109 start()
 110 {
 111         local zram_size="$( zram_size )"
 112         local zram_dev
 113
 114         if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
 115                 logger -s -t zram_start -p daemon.notice "[OK] zram swap is already mounted"
 116                 return 1
 117         fi
 118
 119         zram_dev="$( zram_getdev )"
 120         zram_applicable "$zram_dev" || return 1
 121
 122         logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MegaBytes)"
 123
 124         zram_reset "$zram_dev" "enforcing defaults"
 125         zram_comp_algo "$zram_dev"
 126         zram_comp_streams "$zram_dev"
 127         echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename "$zram_dev" )/disksize"
 128         mkswap "$zram_dev"
 129         swapon "$zram_dev"
 130 }
 131
 132 stop()
 133 {
 134         local zram_dev
 135
 136         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 137                 logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
 138                 swapoff "$zram_dev" && zram_reset "$zram_dev" "claiming memory back"
 139                 local dev_index="$( echo $zram_dev | grep -o "[0-9]*$" )"
 140                 if [ $dev_index -ne 0 ]; then
 141                         logger -s -t zram_stop -p daemon.debug "removing zram $zram_dev"
 142                         echo $dev_index > /sys/class/zram-control/hot_remove
 143                 fi
 144         } done
 145 }
 146