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 Z-RAM swap dev's"
   6 extra_command "status" "Print out information & statistics about Z-RAM 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_applicable()
  29 {
  30         local zram_dev="$1"
  31
  32         [ -e "$zram_dev" ] || {
  33                 logger -s -t zram_applicable -p daemon.crit "[ERROR] device '$zram_dev' not found"
  34                 return 1
  35         }
  36
  37         [ -x /sbin/mkswap ] || {
  38                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'BusyBox mkswap' not installed"
  39                 return 1
  40         }
  41
  42         [ -x /sbin/swapon ] || {
  43                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'BusyBox swapon' not installed"
  44                 return 1
  45         }
  46
  47         [ -x /sbin/swapoff ] || {
  48                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'BusyBox swapoff' not installed"
  49                 return 1
  50         }
  51 }
  52
  53 zram_dev()
  54 {
  55         local idx="$1"
  56         echo "/dev/zram${idx:-0}"
  57 }
  58
  59 zram_reset()
  60 {
  61         local dev="$1"
  62         local message="$2"
  63         local proc_entry="/sys/block/$( basename "$dev" )/reset"
  64
  65         logger -s -t zram_reset -p daemon.debug "$message via $proc_entry"
  66         echo "1" >"$proc_entry"
  67 }
  68
  69 zram_getdev()
  70 {
  71         #get unallocated zram dev
  72         local zdev=$( zram_dev )
  73
  74         if [ "$(mount | grep $zdev)" ]; then
  75                 local idx=$(cat /sys/class/zram-control/hot_add)
  76                 zdev="$( zram_dev $idx )"
  77         fi
  78
  79         echo $zdev
  80 }
  81
  82 zram_comp_algo()
  83 {
  84         local dev="$1"
  85         local zram_comp_algo="$( uci -q get system.@system[0].zram_comp_algo )"
  86
  87         if [ -z "$zram_comp_algo" ]; then
  88                 # lzo-rle fails on small RAM devices, default to lzo, which is always available
  89                 zram_comp_algo="lzo"
  90         fi
  91
  92         if [ $(grep -c "$zram_comp_algo" /sys/block/$( basename $dev )/comp_algorithm) -ne 0 ]; then
  93                 logger -s -t zram_comp_algo -p daemon.debug "Set compression algorithm '$zram_comp_algo' for zram '$dev'"
  94                 echo $zram_comp_algo > "/sys/block/$( basename $dev )/comp_algorithm"
  95         else
  96                 logger -s -t zram_comp_algo -p daemon.debug "Compression algorithm '$zram_comp_algo' is not supported for '$dev'"
  97         fi
  98 }
  99
 100 #print various stats info about zram swap device
 101 zram_stats()
 102 {
 103         local zdev="/sys/block/$( basename "$1" )"
 104
 105         printf "\nGathering stats info for zram device \"$( basename "$1" )\"\n\n"
 106
 107         printf "Z-RAM\n-----\n"
 108         printf "%-25s - %s\n" "Block device" $zdev
 109         awk '{ printf "%-25s - %d MiB\n", "Device size", $1/1024/1024 }' <$zdev/disksize
 110         printf "%-25s - %s\n" "Compression algo" "$(cat $zdev/comp_algorithm)"
 111
 112         awk 'BEGIN { fmt = "%-25s - %.2f %s\n"
 113                 fmt2 = "%-25s - %d\n"
 114                 print "\nDATA\n----" }
 115                 { printf fmt, "Original data size", $1/1024/1024, "MiB"
 116                 printf fmt, "Compressed data size", $2/1024/1024, "MiB"
 117                 printf fmt, "Compress ratio", $1/$2, ""
 118                 print "\nMEMORY\n------"
 119                 printf fmt, "Memory used, total", $3/1024/1024, "MiB"
 120                 printf fmt, "Allocator overhead", ($3-$2)/1024/1024, "MiB"
 121                 printf fmt, "Allocator efficiency", $2/$3*100, "%"
 122                 printf fmt, "Maximum memory ever used", $5/1024/1024, "MiB"
 123                 printf fmt, "Memory limit", $4/1024/1024, "MiB"
 124                 print "\nPAGES\n-----"
 125                 printf fmt2, "Same pages count", $6
 126                 printf fmt2, "Pages compacted", $7 }' <$zdev/mm_stat
 127
 128         awk '{ printf "%-25s - %d\n", "Free pages discarded", $4 }' <$zdev/io_stat
 129 }
 130
 131 zram_compact()
 132 {
 133         # compact zram device (reduce memory allocation overhead)
 134         local zdev="/sys/block/$( basename "$1" )"
 135
 136         local old_mem_used=$(awk '{print $3}' <$zdev/mm_stat)
 137         local old_overhead=$(awk '{print $3-$2}' <$zdev/mm_stat)
 138
 139         echo 1 > $zdev/compact
 140
 141         # If not running interactively, than just return
 142         [ -z "$PS1" ] && return 0
 143
 144         echo ""
 145         echo "Compacting zram device $zdev"
 146         awk -v old_mem="$old_mem_used" -v ovr="$old_overhead" 'BEGIN { fmt = "%-25s - %.1f %s\n" }
 147                 { printf fmt, "Memory usage reduced by ", (old_mem-$3)/1024/1024, "MiB"
 148                 printf fmt, "Overhead reduced by", (ovr-($3-$2))/ovr*100, "%" }' <$zdev/mm_stat
 149 }
 150
 151 start()
 152 {
 153         if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
 154                 logger -s -t zram_start -p daemon.notice "[OK] zram swap is already mounted"
 155                 return 1
 156         fi
 157
 158         local zram_size="$( zram_getsize )"
 159         local zram_dev="$( zram_getdev )"
 160         zram_applicable "$zram_dev" || return 1
 161         local zram_priority="$( uci -q get system.@system[0].zram_priority )"
 162         zram_priority=${zram_priority:+-p $zram_priority}
 163
 164         logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MegaBytes)"
 165
 166         zram_reset "$zram_dev" "enforcing defaults"
 167         zram_comp_algo "$zram_dev"
 168         echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename "$zram_dev" )/disksize"
 169         /sbin/mkswap "$zram_dev"
 170         /sbin/swapon -d $zram_priority "$zram_dev"
 171 }
 172
 173 stop()
 174 {
 175         local zram_dev
 176
 177         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 178                 logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
 179                 /sbin/swapoff "$zram_dev" && zram_reset "$zram_dev" "claiming memory back"
 180                 local dev_index="$( echo $zram_dev | grep -o "[0-9]*$" )"
 181                 if [ $dev_index -ne 0 ]; then
 182                         logger -s -t zram_stop -p daemon.debug "removing zram $zram_dev"
 183                         echo $dev_index > /sys/class/zram-control/hot_remove
 184                 fi
 185         } done
 186 }
 187
 188 # show memory stats for all zram swaps
 189 status()
 190 {
 191         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 192                 zram_stats "$zram_dev"
 193         } done
 194 }
 195
 196 # trigger compaction for all zram swaps
 197 compact()
 198 {
 199         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 200                 zram_compact "$zram_dev"
 201         } done
 202 }