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

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#!/bin/sh /etc/rc.common
START=15
ram_size()
{
local line
while read line; do case "$line" in MemTotal:*) set $line; echo "$2"; break ;; esac; done </proc/meminfo
}
zram_size() # in megabytes
{
local zram_size="$( uci -q get system.@system[0].zram_size_mb )"
local ram_size="$( ram_size )"
if [ -z "$zram_size" ]; then
# e.g. 6mb for 16mb-routers or 61mb for 128mb-routers
echo $(( $ram_size / 2048 ))
else
echo "$zram_size"
fi
}
zram_applicable()
{
local zram_dev="$1"
grep -sq ^"$zram_dev " /proc/swaps && {
logger -s -t zram_applicable -p daemon.notice "[OK] '$zram_dev' already active"
return 1
}
[ -e "$zram_dev" ] || {
logger -s -t zram_applicable -p daemon.crit "[ERROR] device '$zram_dev' not found"
return 1
}
which mkswap >/dev/null || {
logger -s -t zram_applicable -p daemon.err "[ERROR] 'mkswap' not installed"
return 1
}
which swapon >/dev/null || {
logger -s -t zram_applicable -p daemon.err "[ERROR] 'swapon' not installed"
return 1
}
which swapoff >/dev/null || {
logger -s -t zram_applicable -p daemon.err "[ERROR] 'swapoff' not installed"
return 1
}
}
zram_dev()
{
local core="$1"
echo "/dev/zram${core:-0}"
}
zram_reset()
{
local dev="$1"
local message="$2"
local proc_entry="/sys/block/$( basename "$dev" )/reset"
logger -s -t zram_reset -p daemon.debug "$message via $proc_entry"
echo "1" >"$proc_entry"
}
list_cpu_idx()
{
# Offset by 1 if /dev/zram0 is in use by /tmp
if [ "$(mount | grep /dev/zram0)" ]; then
local line i=1
# Hot-add new ZRAM device (if necessary)
if [ ! -b /dev/zram1 ]; then
cat /sys/class/zram-control/hot_add
fi
else
local line i=0
fi
while read line; do {
case "$line" in
[Pp]rocessor*)
echo $i
i=$(( $i + 1 ))
;;
esac
} done <"/proc/cpuinfo"
}
start()
{
# http://shmilyxbq-compcache.googlecode.com/hg/README
# if >1 cpu_core, reinit kmodule with e.g. num_devices=4
local zram_size="$( zram_size )"
local zram_dev core
for core in $( list_cpu_idx ); do {
zram_dev="$( zram_dev "$core" )"
zram_applicable "$zram_dev" || return 1
logger -s -t zram_start -p daemon.debug "activating '$zram_dev' for swapping ($zram_size MegaBytes)"
zram_reset "$zram_dev" "enforcing defaults"
echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename $zram_dev )/disksize"
mkswap "$zram_dev"
swapon "$zram_dev"
} done
}
stop()
{
local zram_dev proc_entry
for core in $( list_cpu_idx ); do {
zram_dev="$( zram_dev "$core" )"
proc_entry="/sys/block/$( basename "$zram_dev" )/reset"
grep -sq ^"$zram_dev " /proc/swaps && {
logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
swapoff "$zram_dev"
}
zram_reset "$zram_dev" "claiming memory back"
} done
}