#!/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() { local line i=0 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 }