96dc819c25
resolves: bz1896698
upstream: fedora
conflict: none
commit 0311f6e25b
Author: Tao Liu <ltao@redhat.com>
Date: Wed Jan 5 17:42:12 2022 +0800
Set zstd as the default compression method for kdump initrd
zstd has better compression ratio and time consumption balance.
When no customized compression method specified in kdump.conf,
we will use zstd as the default compression method.
**The test method:
I installed kexec-tools with and without the patch, executing the following
command for 4 times, and calculate the averange time:
$ rm -f /boot/initramfs-*kdump.img && time kdumpctl rebuild && \
ls -ail /boot/initramfs-*kdump.img
**The test result:
Bare metal x86_64 machine:
dracut with squash module
zlib lzo xz lz4 zstd
real 10.6282 11.0398 11.395 8.6424 10.1676
user 9.8932 11.9072 14.2304 2.8286 8.6468
sys 3.523 3.4626 3.6028 3.5 3.4942
size of
kdump.img 30575616 31419392 27102208 36666368 29236224
dracut without squash module
zlib lzo xz lz4 zstd
real 9.509 19.4876 11.6724 9.0338 10.267
user 10.6028 14.516 17.8662 4.0476 9.0936
sys 2.942 2.9184 3.0662 2.9232 3.0662
size of
kdump.img 19247949 19958120 14505056 21112544 17007764
PowerVM hosted ppc64le VM:
dracut with squash module | dracut without sqaush module
zlib zstd | zlib zstd
real 10.6742 10.7572 | 9.7676 10.5722
user 18.754 19.8338 | 20.7932 13.179
sys 1.8358 1.864 | 1.637 1.663
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size of |
kdump.img 36917248 35467264 | 21441323 19007108
**discussion
zstd has a better compression ratio and time consumption balance.
Acked-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Tao Liu <ltao@redhat.com>
Signed-off-by: Tao Liu <ltao@redhat.com>
72 lines
2.3 KiB
Bash
72 lines
2.3 KiB
Bash
#!/bin/bash --norc
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# Generate an initramfs image that isolates dump capture capability within
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# the default initramfs using zz-fadumpinit dracut module.
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if [[ -f /etc/sysconfig/kdump ]]; then
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. /etc/sysconfig/kdump
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fi
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[[ $dracutbasedir ]] || dracutbasedir=/usr/lib/dracut
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. $dracutbasedir/dracut-functions.sh
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. /lib/kdump/kdump-lib.sh
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. /lib/kdump/kdump-logger.sh
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#initiate the kdump logger
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if ! dlog_init; then
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echo "mkfadumprd: failed to initiate the kdump logger."
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exit 1
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fi
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MKFADUMPRD_TMPDIR="$(mktemp -d -t mkfadumprd.XXXXXX)"
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[ -d "$MKFADUMPRD_TMPDIR" ] || perror_exit "mkfadumprd: mktemp -d -t mkfadumprd.XXXXXX failed."
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trap '
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ret=$?;
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[[ -d $MKFADUMPRD_TMPDIR ]] && rm --one-file-system -rf -- "$MKFADUMPRD_TMPDIR";
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exit $ret;
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' EXIT
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# clean up after ourselves no matter how we die.
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trap 'exit 1;' SIGINT
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MKDUMPRD="/sbin/mkdumprd -f"
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# Default boot initramfs to be rebuilt
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REBUILD_INITRD="$1" && shift
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TARGET_INITRD="$1" && shift
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FADUMP_INITRD="$MKFADUMPRD_TMPDIR/fadump.img"
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### First build an initramfs with dump capture capability
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# this file tells the initrd is fadump enabled
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touch "$MKFADUMPRD_TMPDIR/fadump.initramfs"
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ddebug "rebuild fadump initrd: $FADUMP_INITRD $DEFAULT_INITRD $KDUMP_KERNELVER"
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if ! $MKDUMPRD "$FADUMP_INITRD" -i "$MKFADUMPRD_TMPDIR/fadump.initramfs" /etc/fadump.initramfs; then
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perror_exit "mkfadumprd: failed to build image with dump capture support"
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fi
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### Unpack the initramfs having dump capture capability
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mkdir -p "$MKFADUMPRD_TMPDIR/fadumproot"
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if ! (pushd "$MKFADUMPRD_TMPDIR/fadumproot" > /dev/null && lsinitrd --unpack "$FADUMP_INITRD" &&
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popd > /dev/null); then
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derror "mkfadumprd: failed to unpack '$MKFADUMPRD_TMPDIR'"
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exit 1
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fi
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### Pack it into the normal boot initramfs with zz-fadumpinit module
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_dracut_isolate_args=(
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--rebuild "$REBUILD_INITRD" --add zz-fadumpinit
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-i "$MKFADUMPRD_TMPDIR/fadumproot" /fadumproot
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-i "$MKFADUMPRD_TMPDIR/fadumproot/usr/lib/dracut/hostonly-kernel-modules.txt"
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/usr/lib/dracut/fadump-kernel-modules.txt
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)
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if is_squash_available; then
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_dracut_isolate_args+=(--add squash)
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fi
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if ! have_compression_in_dracut_args; then
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_dracut_isolate_args+=(--compress zstd)
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fi
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if ! dracut --force --quiet "${_dracut_isolate_args[@]}" "$@" "$TARGET_INITRD"; then
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perror_exit "mkfadumprd: failed to setup '$TARGET_INITRD' with dump capture capability"
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fi
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