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

   1 #!/bin/sh /etc/rc.common
   2
   3 START=15
   4
   5 EXTRA_COMMANDS="compact status"
   6 EXTRA_HELP="        compact trigger compaction for all Z-RAM swap dev's
   7         status  print out status information & statistics about Z-RAM swap devices"
   8
   9 ram_getsize()
  10 {
  11         local line
  12
  13         while read line; do case "$line" in MemTotal:*) set $line; echo "$2"; break ;; esac; done </proc/meminfo
  14 }
  15
  16 zram_getsize()  # in megabytes
  17 {
  18         local zram_size="$( uci -q get system.@system[0].zram_size_mb )"
  19         local ram_size="$( ram_getsize )"
  20
  21         if [ -z "$zram_size" ]; then
  22                 # e.g. 6mb for 16mb-routers or 61mb for 128mb-routers
  23                 echo $(( ram_size / 2048 ))
  24         else
  25                 echo "$zram_size"
  26         fi
  27 }
  28
  29 zram_applicable()
  30 {
  31         local zram_dev="$1"
  32
  33         [ -e "$zram_dev" ] || {
  34                 logger -s -t zram_applicable -p daemon.crit "[ERROR] device '$zram_dev' not found"
  35                 return 1
  36         }
  37
  38         [ -x /sbin/mkswap ] || {
  39                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'BusyBox mkswap' not installed"
  40                 return 1
  41         }
  42
  43         [ -x /sbin/swapon ] || {
  44                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'BusyBox swapon' not installed"
  45                 return 1
  46         }
  47
  48         [ -x /sbin/swapoff ] || {
  49                 logger -s -t zram_applicable -p daemon.err "[ERROR] 'BusyBox swapoff' not installed"
  50                 return 1
  51         }
  52 }
  53
  54 zram_dev()
  55 {
  56         local idx="$1"
  57         echo "/dev/zram${idx:-0}"
  58 }
  59
  60 zram_reset()
  61 {
  62         local dev="$1"
  63         local message="$2"
  64         local proc_entry="/sys/block/$( basename "$dev" )/reset"
  65
  66         logger -s -t zram_reset -p daemon.debug "$message via $proc_entry"
  67         echo "1" >"$proc_entry"
  68 }
  69
  70 zram_getdev()
  71 {
  72         #get unallocated zram dev
  73         local zdev=$( zram_dev )
  74
  75         if [ "$(mount | grep $zdev)" ]; then
  76                 local idx=$(cat /sys/class/zram-control/hot_add)
  77                 zdev="$( zram_dev $idx )"
  78         fi
  79
  80         echo $zdev
  81 }
  82
  83 zram_comp_algo()
  84 {
  85         local dev="$1"
  86         local zram_comp_algo="$( uci -q get system.@system[0].zram_comp_algo )"
  87
  88         if [ -z "$zram_comp_algo" ]; then
  89                 # lzo-rle fails on small RAM devices, default to lzo, which is always available
  90                 zram_comp_algo="lzo"
  91         fi
  92
  93         if [ $(grep -c "$zram_comp_algo" /sys/block/$( basename $dev )/comp_algorithm) -ne 0 ]; then
  94                 logger -s -t zram_comp_algo -p daemon.debug "Set compression algorithm '$zram_comp_algo' for zram '$dev'"
  95                 echo $zram_comp_algo > "/sys/block/$( basename $dev )/comp_algorithm"
  96         else
  97                 logger -s -t zram_comp_algo -p daemon.debug "Compression algorithm '$zram_comp_algo' is not supported for '$dev'"
  98         fi
  99 }
 100
 101 zram_comp_streams()
 102 {
 103         local dev="$1"
 104         local logical_cpus=$( grep -ci "^processor" /proc/cpuinfo )
 105         [ $logical_cpus -gt 1 ] || return 1
 106         local zram_comp_streams="$( uci -q get system.@system[0].zram_comp_streams )"
 107         [ -n "$zram_comp_streams" ] && [ "$zram_comp_streams" -le "$logical_cpus" ] || zram_comp_streams=$logical_cpus
 108         if [ -e /sys/block/$( basename $dev )/max_comp_streams ]; then
 109                 logger -s -t zram_comp_streams -p daemon.debug "Set max compression streams to '$zram_comp_streams' for zram '$dev'"
 110                 echo $zram_comp_streams > /sys/block/$( basename $dev )/max_comp_streams
 111         fi
 112 }
 113
 114 #print various stats info about zram swap device
 115 zram_stats()
 116 {
 117         local zdev="/sys/block/$( basename "$1" )"
 118
 119         printf "\nGathering stats info for zram device \"$( basename "$1" )\"\n\n"
 120
 121         printf "Z-RAM\n-----\n"
 122         printf "%-25s - %s\n" "Block device" $zdev
 123         awk '{ printf "%-25s - %d MiB\n", "Device size", $1/1024/1024 }' <$zdev/disksize
 124         printf "%-25s - %s\n" "Compression algo" "$(cat $zdev/comp_algorithm)"
 125         printf "%-25s - %s\n" "Compression streams" "$( cat $zdev/max_comp_streams)"
 126
 127         awk 'BEGIN { fmt = "%-25s - %.2f %s\n"
 128                 fmt2 = "%-25s - %d\n"
 129                 print "\nDATA\n----" }
 130                 { printf fmt, "Original data size", $1/1024/1024, "MiB"
 131                 printf fmt, "Compressed data size", $2/1024/1024, "MiB"
 132                 printf fmt, "Compress ratio", $1/$2, ""
 133                 print "\nMEMORY\n------"
 134                 printf fmt, "Memory used, total", $3/1024/1024, "MiB"
 135                 printf fmt, "Allocator overhead", ($3-$2)/1024/1024, "MiB"
 136                 printf fmt, "Allocator efficiency", $2/$3*100, "%"
 137                 printf fmt, "Maximum memory ever used", $5/1024/1024, "MiB"
 138                 printf fmt, "Memory limit", $4/1024/1024, "MiB"
 139                 print "\nPAGES\n-----"
 140                 printf fmt2, "Same pages count", $6
 141                 printf fmt2, "Pages compacted", $7 }' <$zdev/mm_stat
 142
 143         awk '{ printf "%-25s - %d\n", "Free pages discarded", $4 }' <$zdev/io_stat
 144 }
 145
 146 zram_compact()
 147 {
 148         # compact zram device (reduce memory allocation overhead)
 149         local zdev="/sys/block/$( basename "$1" )"
 150
 151         local old_mem_used=$(awk '{print $3}' <$zdev/mm_stat)
 152         local old_overhead=$(awk '{print $3-$2}' <$zdev/mm_stat)
 153
 154         echo 1 > $zdev/compact
 155
 156         # If not running interactively, than just return
 157         [ -z "$PS1" ] && return 0
 158
 159         echo ""
 160         echo "Compacting zram device $zdev"
 161         awk -v old_mem="$old_mem_used" -v ovr="$old_overhead" 'BEGIN { fmt = "%-25s - %.1f %s\n" }
 162                 { printf fmt, "Memory usage reduced by ", (old_mem-$3)/1024/1024, "MiB"
 163                 printf fmt, "Overhead reduced by", (ovr-($3-$2))/ovr*100, "%" }' <$zdev/mm_stat
 164 }
 165
 166 start()
 167 {
 168         if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
 169                 logger -s -t zram_start -p daemon.notice "[OK] zram swap is already mounted"
 170                 return 1
 171         fi
 172
 173         local zram_size="$( zram_getsize )"
 174         local zram_dev="$( zram_getdev )"
 175         zram_applicable "$zram_dev" || return 1
 176         local zram_priority="$( uci -q get system.@system[0].zram_priority )"
 177         zram_priority=${zram_priority:+-p $zram_priority}
 178
 179         logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MegaBytes)"
 180
 181         zram_reset "$zram_dev" "enforcing defaults"
 182         zram_comp_algo "$zram_dev"
 183         zram_comp_streams "$zram_dev"
 184         echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename "$zram_dev" )/disksize"
 185         /sbin/mkswap "$zram_dev"
 186         /sbin/swapon -d $zram_priority "$zram_dev"
 187 }
 188
 189 stop()
 190 {
 191         local zram_dev
 192
 193         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 194                 logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
 195                 /sbin/swapoff "$zram_dev" && zram_reset "$zram_dev" "claiming memory back"
 196                 local dev_index="$( echo $zram_dev | grep -o "[0-9]*$" )"
 197                 if [ $dev_index -ne 0 ]; then
 198                         logger -s -t zram_stop -p daemon.debug "removing zram $zram_dev"
 199                         echo $dev_index > /sys/class/zram-control/hot_remove
 200                 fi
 201         } done
 202 }
 203
 204 # show memory stats for all zram swaps
 205 status()
 206 {
 207         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 208                 zram_stats "$zram_dev"
 209         } done
 210 }
 211
 212 # trigger compaction for all zram swaps
 213 compact()
 214 {
 215         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 216                 zram_compact "$zram_dev"
 217         } done
 218 }