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

   1 #!/bin/sh /etc/rc.common
   2
   3 START=15
   4
   5 extra_command "compact" "Trigger compaction for all zram swap devices"
   6 extra_command "status" "Print out information & statistics about zram swap devices"
   7
   8 ram_getsize()
   9 {
  10         local line
  11
  12         while read line; do case "$line" in MemTotal:*) set $line; echo "$2"; break ;; esac; done </proc/meminfo
  13 }
  14
  15 zram_getsize()  # in megabytes
  16 {
  17         local zram_size="$( uci -q get system.@system[0].zram_size_mb )"
  18         local ram_size="$( ram_getsize )"
  19
  20         if [ -z "$zram_size" ]; then
  21                 # e.g. 6mb for 16mb-routers or 61mb for 128mb-routers
  22                 echo $(( ram_size / 2048 ))
  23         else
  24                 echo "$zram_size"
  25         fi
  26 }
  27
  28 zram_dev()
  29 {
  30         local idx="$1"
  31         echo "/dev/zram${idx:-0}"
  32 }
  33
  34 zram_reset()
  35 {
  36         local dev="$1"
  37         local message="$2"
  38         local proc_entry="/sys/block/$( basename "$dev" )/reset"
  39
  40         logger -s -t zram_reset -p daemon.debug "$message via $proc_entry"
  41         echo "1" >"$proc_entry"
  42 }
  43
  44 zram_getdev()
  45 {
  46         #get unallocated zram dev
  47         local zdev=$( zram_dev )
  48
  49         if [ "$(mount | grep $zdev)" ]; then
  50                 local idx=$(cat /sys/class/zram-control/hot_add)
  51                 zdev="$( zram_dev $idx )"
  52         fi
  53
  54         echo $zdev
  55 }
  56
  57 zram_comp_algo()
  58 {
  59         local dev="$1"
  60         local zram_comp_algo="$( uci -q get system.@system[0].zram_comp_algo )"
  61
  62         if [ -z "$zram_comp_algo" ]; then
  63                 # default to lzo, which is always available
  64                 zram_comp_algo="lzo"
  65         fi
  66
  67         if [ $(grep -c "$zram_comp_algo" /sys/block/$( basename $dev )/comp_algorithm) -ne 0 ]; then
  68                 logger -s -t zram_comp_algo -p daemon.debug "set compression algorithm '$zram_comp_algo' for zram '$dev'"
  69                 echo $zram_comp_algo > "/sys/block/$( basename $dev )/comp_algorithm"
  70         else
  71                 logger -s -t zram_comp_algo -p daemon.debug "compression algorithm '$zram_comp_algo' is not supported for '$dev'"
  72         fi
  73 }
  74
  75 #print various stats info about zram swap device
  76 zram_stats()
  77 {
  78         local zdev="/sys/block/$( basename "$1" )"
  79
  80         printf "\nGathering stats info for zram device \"$( basename "$1" )\"\n\n"
  81
  82         printf "ZRAM\n----\n"
  83         printf "%-25s - %s\n" "Block device" $zdev
  84         awk '{ printf "%-25s - %d MiB\n", "Device size", $1/1024/1024 }' <$zdev/disksize
  85         printf "%-25s - %s\n" "Compression algo" "$(cat $zdev/comp_algorithm)"
  86
  87         awk 'BEGIN { fmt = "%-25s - %.2f %s\n"
  88                 fmt2 = "%-25s - %d\n"
  89                 print "\nDATA\n----" }
  90                 { printf fmt, "Original data size", $1/1024/1024, "MiB"
  91                 printf fmt, "Compressed data size", $2/1024/1024, "MiB"
  92                 printf fmt, "Compress ratio", $1/$2, ""
  93                 print "\nMEMORY\n------"
  94                 printf fmt, "Memory used, total", $3/1024/1024, "MiB"
  95                 printf fmt, "Allocator overhead", ($3-$2)/1024/1024, "MiB"
  96                 printf fmt, "Allocator efficiency", $2/$3*100, "%"
  97                 printf fmt, "Maximum memory ever used", $5/1024/1024, "MiB"
  98                 printf fmt, "Memory limit", $4/1024/1024, "MiB"
  99                 print "\nPAGES\n-----"
 100                 printf fmt2, "Same pages count", $6
 101                 printf fmt2, "Pages compacted", $7 }' <$zdev/mm_stat
 102
 103         awk '{ printf "%-25s - %d\n", "Free pages discarded", $4 }' <$zdev/io_stat
 104 }
 105
 106 zram_compact()
 107 {
 108         # compact zram device (reduce memory allocation overhead)
 109         local zdev="/sys/block/$( basename "$1" )"
 110
 111         local old_mem_used=$(awk '{print $3}' <$zdev/mm_stat)
 112         local old_overhead=$(awk '{print $3-$2}' <$zdev/mm_stat)
 113
 114         echo 1 > $zdev/compact
 115
 116         # If not running interactively, than just return
 117         [ -z "$PS1" ] && return 0
 118
 119         echo ""
 120         echo "Compacting zram device $zdev"
 121         awk -v old_mem="$old_mem_used" -v ovr="$old_overhead" 'BEGIN { fmt = "%-25s - %.1f %s\n" }
 122                 { printf fmt, "Memory usage reduced by ", (old_mem-$3)/1024/1024, "MiB"
 123                 printf fmt, "Overhead reduced by", (ovr-($3-$2))/ovr*100, "%" }' <$zdev/mm_stat
 124 }
 125
 126 start()
 127 {
 128         [ -e /proc/swaps ] || {
 129                 logger -s -t zram_start -p daemon.crit "kernel doesn't support swap"
 130                 return 1
 131         }
 132
 133         if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
 134                 logger -s -t zram_start -p daemon.notice "zram swap is already mounted"
 135                 return 1
 136         fi
 137
 138         local zram_dev="$( zram_getdev )"
 139
 140         [ -e "$zram_dev" ] || {
 141                 logger -s -t zram_start -p daemon.crit "[ERROR] device '$zram_dev' not found"
 142                 return 1
 143         }
 144
 145         local zram_size="$( zram_getsize )"
 146         local zram_priority="$( uci -q get system.@system[0].zram_priority )"
 147
 148         if [ -z "$zram_priority" ]; then
 149                 zram_priority="100"
 150         fi
 151
 152         logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MiB)"
 153
 154         zram_reset "$zram_dev" "enforcing defaults"
 155         zram_comp_algo "$zram_dev"
 156         echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename "$zram_dev" )/disksize"
 157         busybox mkswap "$zram_dev"
 158         busybox swapon -d -p $zram_priority "$zram_dev"
 159 }
 160
 161 stop()
 162 {
 163         local zram_dev
 164
 165         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 166                 logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
 167                 busybox swapoff "$zram_dev" && zram_reset "$zram_dev" "claiming memory back"
 168                 local dev_index="$( echo $zram_dev | grep -o "[0-9]*$" )"
 169                 if [ $dev_index -ne 0 ]; then
 170                         logger -s -t zram_stop -p daemon.debug "removing zram $zram_dev"
 171                         echo $dev_index > /sys/class/zram-control/hot_remove
 172                 fi
 173         } done
 174 }
 175
 176 # show memory stats for all zram swaps
 177 status()
 178 {
 179         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 180                 zram_stats "$zram_dev"
 181         } done
 182 }
 183
 184 # trigger compaction for all zram swaps
 185 compact()
 186 {
 187         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 188                 zram_compact "$zram_dev"
 189         } done
 190 }