Merge pull request #2 from highvoltage/devel

Devel

README.md

@@ -1,27 +1,27 @@
 zram-tools
 ==========
 
-Scripts for managing zram swap devices.
+Scripts for managing zram devices, currently only for zramswap.
 
-zramswap-start
+zramswap start
 --------------
 
 Sets up zram devices and initializes swap. zram doesn't natively support
 multiple processors, so by default a zram device is set up for every
 core and then swap is initialized on those devices. This is configurable
 in the zramswap config file.
 
-zramswap-stop
+zramswap stop
 -------------
 
 Removes all current zram swap spaces and devices.
 
-zramswap-stat
--------------
+zramswap status
+---------------
 
 shows information on data stored in zram swap.
 
 /etc/default/zramswap
 ---------------------
 
-Configuration file for zramswap-start
+Configuration file for zramswap

zramswap.sh

@@ -0,0 +1,88 @@
+#!/bin/bash
+# This script does the following:
+# zramswap start:
+#  * zram doesn't natively support multiple CPU cores, so one zram device
+#    is created for every CPU core minus one)
+#  * Space is assigned to each zram device, then swap is initialized on
+#    there
+# zramswap stop:
+#  * Somewhat potentially dangerous, removes zram module at the end
+
+function start {
+    #Set some defaults:
+    ALLOCATION=100 # ZRAM Swap you want assigned, in MiB
+    PRIORITY=100   # Swap priority, see swapon(2) for more details
+
+    # Get amount of available CPU cores, set to 1 if not detected correctly
+    if [ ! -f /proc/cpuinfo ]; then
+        echo "WARNING: Can't find /proc/cpuinfo, is proc mounted?"
+        echo "         Using a single core for zramswap..."
+        cores=1
+    else
+        cores=$(grep -c processor /proc/cpuinfo)
+    fi
+
+    # Override  above from config file, if it exists
+    if [ -f /etc/default/zramswap ]; then
+        . /etc/default/zramswap
+    fi
+
+    ALLOCATION=$((ALLOCATION * 1024 * 1024)) # convert amount from MiB to bytes
+
+    if [ -n "$PERCENTAGE" ]; then
+        totalmemory=$(awk '/MemTotal/{print $2}' /proc/meminfo) # in KiB
+        ALLOCATION=$((totalmemory * 1024 * $PERCENTAGE / 100))
+    fi
+
+    # Initialize zram devices, one device per CPU core
+    modprobe zram num_devices=$cores
+
+    # Assign memory to zram devices, initialize swap and activate
+    # Decrementing $core, because cores start counting at 0
+    for core in $(seq 0 $(($cores - 1))); do
+        echo $(($ALLOCATION / $cores)) > /sys/block/zram$core/disksize
+        mkswap /dev/zram$core
+        swapon -p $PRIORITY /dev/zram$core
+    done
+}
+
+function status {
+    for f in /sys/block/zram*/*_data_size ; do
+        read size < $f
+        what=$(basename $f)
+        eval "$what=\$(($what + $size))"
+    done
+    echo "compr_data_size: $((compr_data_size / 1024)) KiB"
+    echo "orig_data_size:  $((orig_data_size  / 1024)) KiB"
+    echo "print \"compression-ratio: \"; scale=2; $orig_data_size / $compr_data_size" | bc
+}
+
+function stop {
+    for swapspace in $(swapon -s | awk '/zram/{print $1}'); do
+        swapoff $swapspace
+    done
+    modprobe -r zram
+}
+
+function usage {
+    echo "Usage:"
+    echo "   zramswap start - start zram swap"
+    echo "   zramswap stop - stop zram swap"
+    echo "   zramswap status - prints some statistics"
+}
+
+if [ "$1" = "start" ]; then
+    start
+fi
+
+if [ "$1" = "stop" ]; then
+    stop
+fi
+
+if [ "$1" = "status" ]; then
+    status
+fi
+
+if [ "$1" = "" ]; then
+    usage
+fi