Initial commit

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

@@ -0,0 +1,146 @@
+#!/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="$1"
+
+	[ -e "$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 idx="$1"
+	echo "/dev/zram${idx:-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"
+}
+
+zram_getdev()
+{
+	#get unallocated zram dev
+	local zdev=$( zram_dev )
+
+	if [ "$(mount | grep $zdev)" ]; then
+		local idx=`cat /sys/class/zram-control/hot_add`
+		zdev="$( zram_dev $idx )"
+	fi
+
+	echo $zdev
+}
+
+zram_comp_algo()
+{
+	local dev="$1"
+	local zram_comp_algo="$( uci -q get system.@system[0].zram_comp_algo )"
+
+	if [ -z "$zram_comp_algo" ] || [ ! -e /sys/block/$( basename $dev )/comp_algorithm ]; then
+		return 0
+	fi
+
+	if [ `grep -c "$zram_comp_algo" /sys/block/$( basename $dev )/comp_algorithm` -ne 0 ]; then
+		logger -s -t zram_comp_algo -p daemon.debug "Set compression algorithm '$zram_comp_algo' for zram '$dev'"
+		echo $zram_comp_algo > "/sys/block/$( basename $dev )/comp_algorithm"
+	else
+		logger -s -t zram_comp_algo -p daemon.debug "Compression algorithm '$zram_comp_algo' is not supported for '$dev'"
+	fi
+}
+
+zram_comp_streams()
+{
+	local dev="$1"
+	local logical_cpus=$( grep -ci "^processor" /proc/cpuinfo )
+	[ $logical_cpus -gt 1 ] || return 1
+	local zram_comp_streams="$( uci -q get system.@system[0].zram_comp_streams )"
+	[ -n "$zram_comp_streams" ] && [ "$zram_comp_streams" -le "$logical_cpus" ] || zram_comp_streams=$logical_cpus
+	if [ -e /sys/block/$( basename $dev )/max_comp_streams ]; then
+		logger -s -t zram_comp_streams -p daemon.debug "Set max compression streams to '$zram_comp_streams' for zram '$dev'"
+		echo $zram_comp_streams > /sys/block/$( basename $dev )/max_comp_streams
+	fi
+}
+
+start()
+{
+	local zram_size="$( zram_size )"
+	local zram_dev
+
+	if [ $( grep -cs zram /proc/swaps ) -ne 0 ]; then
+		logger -s -t zram_start -p daemon.notice "[OK] zram swap is already mounted"
+		return 1
+	fi
+
+	zram_dev="$( zram_getdev )"
+	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"
+	zram_comp_algo "$zram_dev"
+	zram_comp_streams "$zram_dev"
+	echo $(( $zram_size * 1024 * 1024 )) >"/sys/block/$( basename "$zram_dev" )/disksize"
+	mkswap "$zram_dev"
+	swapon "$zram_dev"
+}
+
+stop()
+{
+	local zram_dev
+
+	for zram_dev in $( grep zram /proc/swaps |awk '{print $1}' ); do {
+		logger -s -t zram_stop -p daemon.debug "deactivate swap $zram_dev"
+		swapoff "$zram_dev" && zram_reset "$zram_dev" "claiming memory back"
+		local dev_index="$( echo $zram_dev | grep -o "[0-9]*$" )"
+		if [ $dev_index -ne 0 ]; then
+			logger -s -t zram_stop -p daemon.debug "removing zram $zram_dev"
+			echo $dev_index > /sys/class/zram-control/hot_remove
+		fi
+	} done
+}
+