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 zram_comp_streams()
 101 {
 102         local dev="$1"
 103         local logical_cpus=$( grep -ci "^processor" /proc/cpuinfo )
 104         [ $logical_cpus -gt 1 ] || return 1
 105         local zram_comp_streams="$( uci -q get system.@system[0].zram_comp_streams )"
 106         [ -n "$zram_comp_streams" ] && [ "$zram_comp_streams" -le "$logical_cpus" ] || zram_comp_streams=$logical_cpus
 107         if [ -e /sys/block/$( basename $dev )/max_comp_streams ]; then
 108                 logger -s -t zram_comp_streams -p daemon.debug "Set max compression streams to '$zram_comp_streams' for zram '$dev'"
 109                 echo $zram_comp_streams > /sys/block/$( basename $dev )/max_comp_streams
 110         fi
 111 }
 112
 113 #print various stats info about zram swap device
 114 zram_stats()
 115 {
 116         local zdev="/sys/block/$( basename "$1" )"
 117
 118         printf "\nGathering stats info for zram device \"$( basename "$1" )\"\n\n"
 119
 120         printf "Z-RAM\n-----\n"
 121         printf "%-25s - %s\n" "Block device" $zdev
 122         awk '{ printf "%-25s - %d MiB\n", "Device size", $1/1024/1024 }' <$zdev/disksize
 123         printf "%-25s - %s\n" "Compression algo" "$(cat $zdev/comp_algorithm)"
 124         printf "%-25s - %s\n" "Compression streams" "$( cat $zdev/max_comp_streams)"
 125
 126         awk 'BEGIN { fmt = "%-25s - %.2f %s\n"
 127                 fmt2 = "%-25s - %d\n"
 128                 print "\nDATA\n----" }
 129                 { printf fmt, "Original data size", $1/1024/1024, "MiB"
 130                 printf fmt, "Compressed data size", $2/1024/1024, "MiB"
 131                 printf fmt, "Compress ratio", $1/$2, ""
 132                 print "\nMEMORY\n------"
 133                 printf fmt, "Memory used, total", $3/1024/1024, "MiB"
 134                 printf fmt, "Allocator overhead", ($3-$2)/1024/1024, "MiB"
 135                 printf fmt, "Allocator efficiency", $2/$3*100, "%"
 136                 printf fmt, "Maximum memory ever used", $5/1024/1024, "MiB"
 137                 printf fmt, "Memory limit", $4/1024/1024, "MiB"
 138                 print "\nPAGES\n-----"
 139                 printf fmt2, "Same pages count", $6
 140                 printf fmt2, "Pages compacted", $7 }' <$zdev/mm_stat
 141
 142         awk '{ printf "%-25s - %d\n", "Free pages discarded", $4 }' <$zdev/io_stat
 143 }
 144
 145 zram_compact()
 146 {
 147         # compact zram device (reduce memory allocation overhead)
 148         local zdev="/sys/block/$( basename "$1" )"
 149
 150         local old_mem_used=$(awk '{print $3}' <$zdev/mm_stat)
 151         local old_overhead=$(awk '{print $3-$2}' <$zdev/mm_stat)
 152
 153         echo 1 > $zdev/compact
 154
 155         # If not running interactively, than just return
 156         [ -z "$PS1" ] && return 0
 157
 158         echo ""
 159         echo "Compacting zram device $zdev"
 160         awk -v old_mem="$old_mem_used" -v ovr="$old_overhead" 'BEGIN { fmt = "%-25s - %.1f %s\n" }
 161                 { printf fmt, "Memory usage reduced by ", (old_mem-$3)/1024/1024, "MiB"
 162                 printf fmt, "Overhead reduced by", (ovr-($3-$2))/ovr*100, "%" }' <$zdev/mm_stat
 163 }
 164
 165 start()
 166 {
 167         if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
 168                 logger -s -t zram_start -p daemon.notice "[OK] zram swap is already mounted"
 169                 return 1
 170         fi
 171
 172         local zram_size="$( zram_getsize )"
 173         local zram_dev="$( zram_getdev )"
 174         zram_applicable "$zram_dev" || return 1
 175         local zram_priority="$( uci -q get system.@system[0].zram_priority )"
 176         zram_priority=${zram_priority:+-p $zram_priority}
 177
 178         logger -s -t zram_start -p daemon.debug "activating '$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 "$zram_dev" )/disksize"
 184         /sbin/mkswap "$zram_dev"
 185         /sbin/swapon -d $zram_priority "$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 $zram_dev"
 194                 /sbin/swapoff "$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
 203 # show memory stats for all zram swaps
 204 status()
 205 {
 206         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 207                 zram_stats "$zram_dev"
 208         } done
 209 }
 210
 211 # trigger compaction for all zram swaps
 212 compact()
 213 {
 214         for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
 215                 zram_compact "$zram_dev"
 216         } done
 217 }