|
 |
ab92d3 |
From f03ee48fab36a9fe55082f15111771b698081598 Mon Sep 17 00:00:00 2001
|
|
|
ab92d3 |
From: =?UTF-8?q?Renaud=20M=C3=A9trich?= <rmetrich@redhat.com>
|
|
|
ab92d3 |
Date: Wed, 5 May 2021 15:46:08 +0200
|
|
|
ab92d3 |
Subject: [PATCH] fix(dracut-functions): implement a cache for get_maj_min
|
|
|
ab92d3 |
MIME-Version: 1.0
|
|
|
ab92d3 |
Content-Type: text/plain; charset=UTF-8
|
|
|
ab92d3 |
Content-Transfer-Encoding: 8bit
|
|
|
ab92d3 |
|
|
|
ab92d3 |
On systems with a large number of devices, usually multipath devices,
|
|
|
ab92d3 |
dracut can spend a lot of time stat'ing the devices to collect the
|
|
|
ab92d3 |
major/minor numbers, leading to huge slowness rebuilding the initramfs
|
|
|
ab92d3 |
when stat'ing devices is slow (seen with oracleasm file systems in
|
|
|
ab92d3 |
particular).
|
|
|
ab92d3 |
This commit implements a basic cache stored in a file under
|
|
|
ab92d3 |
DRACUT_TMPDIR storing the major:minor corresponding to the specified
|
|
|
ab92d3 |
device.
|
|
|
ab92d3 |
|
|
|
ab92d3 |
Reproducer: create N loopback devices used as a LVM extension to volume
|
|
|
ab92d3 |
group hosting the root file system
|
|
|
ab92d3 |
|
|
|
ab92d3 |
# LVMVG="rhel"
|
|
|
ab92d3 |
# NDEVICES=200
|
|
|
ab92d3 |
# mkdir devices; for i in $(seq 1 $NDEVICES); do
|
|
|
ab92d3 |
truncate -s 10m devices/$i; losetup loop$i devices/$i
|
|
|
ab92d3 |
done
|
|
|
ab92d3 |
# vgextend $LVMVG $(/bin/ls -1 /dev/loop[0-9]*)
|
|
|
ab92d3 |
|
|
|
ab92d3 |
With standard code (tested with RHEL8.3 dracut):
|
|
|
ab92d3 |
|
|
|
ab92d3 |
# dracut -f --debug /tmp/initramfs.img $(uname -r) >/tmp/debug 2>&1
|
|
|
ab92d3 |
# grep -c "stat -L -c" /tmp/debug
|
|
|
ab92d3 |
2440
|
|
|
ab92d3 |
|
|
|
ab92d3 |
With this code:
|
|
|
ab92d3 |
|
|
|
ab92d3 |
# dracut -f --debug /tmp/initramfs.img $(uname -r) >/tmp/debug_optim 2>&1
|
|
|
ab92d3 |
# grep -c "stat -L -c" /tmp/debug_optim
|
|
|
ab92d3 |
205
|
|
|
ab92d3 |
|
|
|
ab92d3 |
Signed-off-by: Renaud Métrich <rmetrich@redhat.com>
|
|
|
ab92d3 |
(cherry picked from commit c3bb9d18dceed7db6d16f9c2a7f682c5934099d7)
|
|
|
ab92d3 |
|
|
|
ab92d3 |
Cherry-picked from: c3bb9d18dceed7db6d16f9c2a7f682c5934099d7
|
|
|
ab92d3 |
Resolves: #1957622
|
|
|
ab92d3 |
---
|
|
|
ab92d3 |
dracut-functions.sh | 10 +++++++---
|
|
|
ab92d3 |
dracut.sh | 4 ++++
|
|
|
ab92d3 |
2 files changed, 11 insertions(+), 3 deletions(-)
|
|
|
ab92d3 |
|
|
|
ab92d3 |
diff --git a/dracut-functions.sh b/dracut-functions.sh
|
|
|
ab92d3 |
index 1431dd18..a221967c 100755
|
|
|
ab92d3 |
--- a/dracut-functions.sh
|
|
|
ab92d3 |
+++ b/dracut-functions.sh
|
|
|
ab92d3 |
@@ -199,12 +199,16 @@ get_fs_env() {
|
|
|
ab92d3 |
# $ get_maj_min /dev/sda2
|
|
|
ab92d3 |
# 8:2
|
|
|
ab92d3 |
get_maj_min() {
|
|
|
ab92d3 |
- local _maj _min _majmin
|
|
|
ab92d3 |
+ local _majmin
|
|
|
ab92d3 |
+ out="$(grep -m1 -oP "^$1 \K\S+$" "${get_maj_min_cache_file:?}")"
|
|
|
ab92d3 |
+ if [ -z "$out" ]; then
|
|
|
ab92d3 |
_majmin="$(stat -L -c '%t:%T' "$1" 2>/dev/null)"
|
|
|
ab92d3 |
- printf "%s" "$((0x${_majmin%:*})):$((0x${_majmin#*:}))"
|
|
|
ab92d3 |
+ out="$(printf "%s" "$((0x${_majmin%:*})):$((0x${_majmin#*:}))")"
|
|
|
ab92d3 |
+ echo "$1 $out" >> "${get_maj_min_cache_file:?}"
|
|
|
ab92d3 |
+ fi
|
|
|
ab92d3 |
+ echo -n "$out"
|
|
|
ab92d3 |
}
|
|
|
ab92d3 |
|
|
|
ab92d3 |
-
|
|
|
ab92d3 |
# get_devpath_block <device>
|
|
|
ab92d3 |
# get the DEVPATH in /sys of a block device
|
|
|
ab92d3 |
get_devpath_block() {
|
|
|
ab92d3 |
diff --git a/dracut.sh b/dracut.sh
|
|
|
ab92d3 |
index 4340e646..f8e68ccb 100755
|
|
|
ab92d3 |
--- a/dracut.sh
|
|
|
ab92d3 |
+++ b/dracut.sh
|
|
|
ab92d3 |
@@ -901,6 +901,10 @@ readonly DRACUT_TMPDIR="$(mktemp -p "$TMPDIR/" -d -t dracut.XXXXXX)"
|
|
|
ab92d3 |
exit 1
|
|
|
ab92d3 |
}
|
|
|
ab92d3 |
|
|
|
ab92d3 |
+# Cache file used to optimize get_maj_min()
|
|
|
ab92d3 |
+declare -x -r get_maj_min_cache_file="${DRACUT_TMPDIR}/majmin_cache"
|
|
|
ab92d3 |
+: > "$get_maj_min_cache_file"
|
|
|
ab92d3 |
+
|
|
|
ab92d3 |
# clean up after ourselves no matter how we die.
|
|
|
ab92d3 |
trap '
|
|
|
ab92d3 |
ret=$?;
|
|
|
ab92d3 |
|