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 $dev )/max_comp_streams
 106         fi
 107 }
 108
 109 zram_stats()
 110 {
 111         #print various stats info about zram swap device
 112         local zdev="/sys/block/$( basename "$1" )"
 113
 114         printf "\nGathering stats info for zram device \"$( basename "$1" )\"\n\n"
 115
 116         printf "Z-RAM\n-----\n"
 117         printf "%-25s - %s\n" "Block device" $zdev
 118         awk '{ printf "%-25s - %d MiB\n", "Device size", $1/1024/1024 }' <$zdev/disksize
 119         printf "%-25s - %s\n" "Compression algo" "$(cat $zdev/comp_algorithm)"
 120         printf "%-25s - %s\n" "Compression streams" "$( cat $zdev/max_comp_streams)"
 121
 122         awk 'BEGIN { fmt = "%-25s - %.2f %s\n"
 123                 fmt2 = "%-25s - %d\n"
 124                 print "\nDATA\n----" }
 125                 { printf fmt, "Original data size", $1/1024/1024, "MiB"
 126                 printf fmt, "Compressed data size", $2/1024/1024, "MiB"
 127                 printf fmt, "Compress ratio", $1/$2, ""
 128                 print "\nMEMORY\n------"
 129                 printf fmt, "Memory used, total", $3/1024/1024, "MiB"
 130                 printf fmt, "Allocator overhead", ($3-$2)/1024/1024, "MiB"
 131                 printf fmt, "Allocator efficiency", $2/$3*100, "%"
 132                 printf fmt, "Maximum memory ever used", $5/1024/1024, "MiB"
 133                 printf fmt, "Memory limit", $4/1024/1024, "MiB"
 134                 print "\nPAGES\n-----"
 135                 printf fmt2, "Same pages count", $6
 136                 printf fmt2, "Pages compacted", $7 }' <$zdev/mm_stat
 137
 138         awk '{ printf "%-25s - %d\n", "Free pages discarded", $4 }' <$zdev/io_stat
 139 }
 140
 141 zram_compact()
 142 {
 143         # compact zram device (reduce memory allocation overhead)
 144         local zdev="/sys/block/$( basename "$1" )"
 145
 146         old_mem_used=`awk '{print $3}' <$zdev/mm_stat`
 147         old_overhead=`awk '{print $3-$2}' <$zdev/mm_stat`
 148
 149         echo ""
 150         echo "Compacting zram device..."
 151         echo 1 > $zdev/compact
 152         awk -v old_mem="$old_mem_used" -v ovr="$old_overhead" 'BEGIN { fmt = "%-25s - %.1f %s\n" }
 153                 { printf fmt, "Memory usage reduced by ", (old_mem-$3)/1024/1024, "MiB"
 154                 printf fmt, "Overhead reduced by", (ovr-($3-$2))/ovr*100, "%" }' <$zdev/mm_stat
 155 }
 156
 157 start()
 158 {
 159         local zram_size="$( zram_size )"
 160         local zram_dev
 161
 162         if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
 163                 logger -s -t zram_start -p daemon.notice "[OK] zram swap is already mounted"
 164                 # If not running interactively, than just quit
 165                 [ -z "$PS1" ] && return 1
 166
 167                 # show memory stats and compact all zram swaps
 168                 for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 169                         zram_compact "$zram_dev"
 170                         zram_stats "$zram_dev"
 171                 } done
 172                 return
 173         fi
 174
 175         zram_dev="$( zram_getdev )"
 176         zram_applicable "$zram_dev" || return 1
 177
 178         logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MegaBytes)"
 179
 180         zram_reset "$zram_dev" "enforcing defaults"
 181         zram_comp_algo "$zram_dev"
 182         zram_comp_streams "$zram_dev"
 183         echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename "$zram_dev" )/disksize"
 184         mkswap "$zram_dev"
 185         swapon "$zram_dev"
 186 }
 187
 188 stop()
 189 {
 190         local zram_dev
 191
 192         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 193                 logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
 194                 swapoff "$zram_dev" && zram_reset "$zram_dev" "claiming memory back"
 195                 local dev_index="$( echo $zram_dev | grep -o "[0-9]*$" )"
 196                 if [ $dev_index -ne 0 ]; then
 197                         logger -s -t zram_stop -p daemon.debug "removing zram $zram_dev"
 198                         echo $dev_index > /sys/class/zram-control/hot_remove
 199                 fi
 200         } done
 201 }
 202