From bef592844bd2cb1c3561f16ce62c31eecd5cc5d5 Mon Sep 17 00:00:00 2001
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Sun, 6 Jan 2013 16:21:29 +0000
Subject: [PATCH] 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.
SVN-Revision: 35025
---
package/busybox/config/util-linux/Config.in | 4 +-
package/kernel/modules/other.mk | 21 ++++
package/zram-swap/Makefile | 46 ++++++++
package/zram-swap/files/etc/init.d/zram | 123 ++++++++++++++++++++
4 files changed, 192 insertions(+), 2 deletions(-)
create mode 100644 package/zram-swap/Makefile
create mode 100644 package/zram-swap/files/etc/init.d/zram
diff --git a/package/busybox/config/util-linux/Config.in b/package/busybox/config/util-linux/Config.in
index 14d4777bea..d60b139a8b 100644
--- a/package/busybox/config/util-linux/Config.in
+++ b/package/busybox/config/util-linux/Config.in
@@ -474,7 +474,7 @@ config BUSYBOX_CONFIG_FEATURE_MDEV_LOAD_FIRMWARE
config BUSYBOX_CONFIG_MKSWAP
bool "mkswap"
- default n
+ default y
help
The mkswap utility is used to configure a file or disk partition as
Linux swap space. This allows Linux to use the entire file or
@@ -652,7 +652,7 @@ config BUSYBOX_CONFIG_SETARCH
config BUSYBOX_CONFIG_SWAPONOFF
bool "swaponoff"
- default n
+ default y
select BUSYBOX_CONFIG_PLATFORM_LINUX
help
This option enables both the 'swapon' and the 'swapoff' utilities.
diff --git a/package/kernel/modules/other.mk b/package/kernel/modules/other.mk
index ddaef8d901..5d3e00a87f 100644
--- a/package/kernel/modules/other.mk
+++ b/package/kernel/modules/other.mk
@@ -747,3 +747,24 @@ define KernelPackage/ikconfig/description
endef
$(eval $(call KernelPackage,ikconfig))
+
+
+define KernelPackage/zram
+ SUBMENU:=$(OTHER_MENU)
+ TITLE:=ZRAM
+ DEPENDS:=@!LINUX_3_3 +kmod-lib-lzo
+ KCONFIG:= \
+ CONFIG_ZSMALLOC \
+ CONFIG_ZRAM \
+ CONFIG_ZRAM_DEBUG=n
+ FILES:= \
+ $(LINUX_DIR)/drivers/staging/zsmalloc/zsmalloc.ko \
+ $(LINUX_DIR)/drivers/staging/zram/zram.ko
+ AUTOLOAD:=$(call AutoLoad,20,zsmalloc zram)
+endef
+
+define KernelPackage/zram/description
+ Compressed RAM block device support
+endef
+
+$(eval $(call KernelPackage,zram))
diff --git a/package/zram-swap/Makefile b/package/zram-swap/Makefile
new file mode 100644
index 0000000000..59a55c4776
--- /dev/null
+++ b/package/zram-swap/Makefile
@@ -0,0 +1,46 @@
+#
+# Copyright (C) 2013 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=zram-swap
+PKG_VERSION:=1
+PKG_RELEASE:=1
+
+PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/zram-swap
+ SECTION:=utils
+ CATEGORY:=Base system
+ DEPENDS:=+kmod-zram +!(BUSYBOX_CONFIG_MKSWAP&&BUSYBOX_CONFIG_SWAPONOFF):swap-utils
+ TITLE:=ZRAM swap scripts
+ PKGARCH:=all
+endef
+
+define Package/zram-swap/description
+ A script to activate swaping on a compressed zram partition. This
+ could be used to increase the available memory, by using compressed
+ memory.
+endef
+
+define Build/Prepare
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+endef
+
+define Package/zram-swap/install
+ $(INSTALL_DIR) $(1)
+ $(CP) ./files/* $(1)/
+endef
+
+$(eval $(call BuildPackage,zram-swap))
diff --git a/package/zram-swap/files/etc/init.d/zram b/package/zram-swap/files/etc/init.d/zram
new file mode 100644
index 0000000000..23de915c8f
--- /dev/null
+++ b/package/zram-swap/files/etc/init.d/zram
@@ -0,0 +1,123 @@
+#!/bin/sh /etc/rc.common
+
+START=15
+
+ram_size()
+{
+ local line
+
+ while read line; do case "$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
+}
+
--
2.34.1