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
This commit is contained in:
Hauke Mehrtens 2013-01-06 16:21:29 +00:00
parent 5154270694
commit bef592844b
4 changed files with 192 additions and 2 deletions

View file

@ -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.

View file

@ -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))

View file

@ -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))

View file

@ -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
}