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authorhauke <hauke@3c298f89-4303-0410-b956-a3cf2f4a3e73>2013-01-06 16:21:29 +0000
committerhauke <hauke@3c298f89-4303-0410-b956-a3cf2f4a3e73>2013-01-06 16:21:29 +0000
commit38cc3e47f517a509152186069c45d20f52e90835 (patch)
treec8f83b7a719fb7d168480afea6939577d79af1ff /package/zram-swap/files
parentcae68530d3b48f9274ee01405c5601bc9450bc14 (diff)
zram: add package to use compressed ram disk for swap
The busybox size is increased by 3.2KByte uncompressed on bcm47xx with this commit. This zram-swap automatically creates a zram device, a swap partition on it and make the kernel swap pages to it. Thank you Bastian Bittorf <bittorf@bluebottle.com> for idea and the script. git-svn-id: svn://svn.openwrt.org/openwrt/trunk@35025 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'package/zram-swap/files')
-rw-r--r--package/zram-swap/files/etc/init.d/zram123
1 files changed, 123 insertions, 0 deletions
diff --git a/package/zram-swap/files/etc/init.d/zram b/package/zram-swap/files/etc/init.d/zram
new file mode 100644
index 000000000..23de915c8
--- /dev/null
+++ b/package/zram-swap/files/etc/init.d/zram
@@ -0,0 +1,123 @@
+#!/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
+}
+