system/swapinzram: Added (Configure a swap block device in RAM).

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackbuilds.org>

system/swapinzram/README

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+# swapinzram for Slackware
+Modified swapinzram script by Didier Spaier  
+http://slackware.uk/slint/x86_64/slint-15.0/source/swapinzram/
+
+
+The package swapinzram is intended to extend the swap spaces available
+beyond swap partitions and swap files, providing swap space in the form
+of a block device in compressed RAM, using the zram kernel module. 
+As the files in it are compressed this results in an increase of the 
+RAM size usable by the system at the cost of a small overhead to 
+compress and decompress the files. 
+
+This can be useful to:
+1. Avoid or at least delay swapping on a mass storage device when 
+available space in RAM decreases. This results in a performance gain 
+because writing in RAM is way faster that on a hard disk or even an SSD
+2. Less writing on a storage devices like flash drives, eMMC, USB flash
+drives or SD card, if the swap partition or file is installed on such 
+devices.
+Beyond the performance gain this also minimizes wearing of the device.
+
+zram can also be used to create block devices in RAM for other usages,
+like to store the files in /tmp or the kernel log, but this is not in
+the scope of this package. However as we pick an available zram device
+id there should be no conflict when adding these features. 
+
+Also in the TODO list, allow to write idle/incompressible pages to a
+backing storage rather than keeping them in memory. The documentation 
+states that the backing storage should be a swap partition, not a swap
+file, but I will check if it's still true.

system/swapinzram/doinst.sh

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+#!/bin/sh
+
+config() {
+  NEW="$1"
+  OLD="$(dirname $NEW)/$(basename $NEW .new)"
+  
+  if [ ! -r $OLD ]; then
+    mv $NEW $OLD
+  elif [ "$(cat $OLD | md5sum)" = "$(cat $NEW | md5sum)" ]; then
+    rm $NEW
+  fi
+}
+
+config etc/swapinzram.conf.new
+config etc/sysctl.d/10-zram.conf.new

system/swapinzram/slack-desc

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+# HOW TO EDIT THIS FILE:
+# The "handy ruler" below makes it easier to edit a package description.
+# Line up the first '|' above the ':' following the base package name, and
+# the '|' on the right side marks the last column you can put a character in.
+# You must make exactly 11 lines for the formatting to be correct. It's also
+# customary to leave one space after the ':' except on otherwise blank lines.
+
+          |-----handy-ruler------------------------------------------------------|
+swapinzram: swapinzram (Configure a swap block device in RAM)
+swapinzram:
+swapinzram: Zram creates a compressed block device in memory, and the RAM
+swapinzram: assigned to it is only used for swapping as-needed (until then, the
+swapinzram: RAM is still available for use by applications).
+swapinzram: Swap data stored is compressed thereby allowing more data to be
+swapinzram: stored in RAM.
+swapinzram:
+swapinzram:
+swapinzram: https://www.kernel.org/doc/html/latest/admin-guide/blockdev/zram.html
+swapinzram:

system/swapinzram/swapinzram.SlackBuild

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+#!/bin/bash
+#
+# Copyright 2022 marav, Paris, FR
+# All rights reserved.
+#
+# Redistribution and use of this script, with or without modification, is
+# permitted provided that the following conditions are met:
+#
+# 1. Redistributions of this script must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
+#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+PRGNAM=swapinzram
+SRC_SCRIPTS="swapinzram-files.tar.gz"
+VERSION=${VERSION:-1.0}
+ARCH=noarch
+BUILD=${BUILD:-1}
+TAG=${TAG:-_SBo}
+PKGTYPE=${PKGTYPE:-tgz}
+
+if [ ! -z "${PRINT_PACKAGE_NAME}" ]; then
+  echo "$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.$PKGTYPE"
+  exit 0
+fi
+
+CWD=$(pwd)
+TMP=${TMP:-/tmp/SBo}
+PKG=$TMP/package-$PRGNAM
+OUTPUT=${OUTPUT:-/tmp}
+
+rm -rf $PKG
+mkdir -p $TMP $PKG
+mkdir -p $PKG/usr/doc/$PRGNAM-$VERSION
+mkdir -p $PKG/{install,etc/rc.d,etc/sysctl.d}
+
+tar -xvf $SRC_SCRIPTS -C $PKG || exit 1
+
+mv $PKG/rc.swapinzram $PKG/etc/rc.d
+    chmod 644 $PKG/etc/rc.d/rc.swapinzram
+    chown root:root -R $PKG/etc/rc.d/rc.swapinzram
+
+mv $PKG/swapinzram.conf $PKG/etc/swapinzram.conf.new
+    chmod 644 $PKG/etc/swapinzram.conf.new
+
+mv $PKG/10-zram.conf $PKG/etc/sysctl.d/10-zram.conf.new
+    chmod 644 $PKG/etc/sysctl.d/10-zram.conf.new
+
+cp $CWD/README $PKG/usr/doc/$PRGNAM-$VERSION/
+cp $CWD/$PRGNAM.SlackBuild $PKG/usr/doc/$PRGNAM-$VERSION/
+    chmod 644 $PKG/usr/doc/$PRGNAM-$VERSION/*
+
+
+mkdir -p $PKG/install
+cat $CWD/doinst.sh > $PKG/install/doinst.sh
+cat $CWD/slack-desc > $PKG/install/slack-desc
+
+cd $PKG
+/sbin/makepkg -l y -c n $OUTPUT/$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.$PKGTYPE

system/swapinzram/swapinzram.info

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+PRGNAM="swapinzram"
+VERSION="1.0"
+HOMEPAGE="https://gitlab.com/maravtdm/swapinzram-slackbuild"
+DOWNLOAD="https://master.dl.sourceforge.net/project/swapinzram-src/swapinzram-files.tar.gz"
+MD5SUM="48d5cdaa3d20013689747d0836dcc98c"
+DOWNLOAD_x86_64=""
+MD5SUM_x86_64=""
+REQUIRES=""
+MAINTAINER="marav"
+EMAIL="marav8@free.fr"