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[PATCH v6 2/5] grub-mkconfig linux_xen: Fix quadratic algorithm for sort
From: |
Mathieu Desnoyers |
Subject: |
[PATCH v6 2/5] grub-mkconfig linux_xen: Fix quadratic algorithm for sorting menu items |
Date: |
Mon, 13 Jun 2022 10:08:23 -0400 |
The current implementation of the 20_linux_xen script implements its
menu items sorting in bash with a quadratic algorithm, calling "sed",
"sort", "head", and "grep" to compare versions between individual lines,
which is annoyingly slow for kernel developers who can easily end up
with 50-100 kernels in their boot partition.
This fix is ported from the 10_linux script, which has a similar
quadratic code pattern.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Cc: xen-devel@lists.xenproject.org
---
Changes since v4:
- Combine sed -e '...' -e '...' into sed -e '...; ...'
---
util/grub.d/20_linux_xen.in | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/util/grub.d/20_linux_xen.in b/util/grub.d/20_linux_xen.in
index 51a983926..4382303c1 100644
--- a/util/grub.d/20_linux_xen.in
+++ b/util/grub.d/20_linux_xen.in
@@ -237,11 +237,17 @@ esac
# yet, so it's empty. In a submenu it will be equal to '\t' (one tab).
submenu_indentation=""
+# Perform a reverse version sort on the entire xen_list and linux_list.
+# Temporarily replace the '.old' suffix by ' 1' and append ' 2' for all
+# other files to order the '.old' files after their non-old counterpart
+# in reverse-sorted order.
+
+reverse_sorted_xen_list=$(echo ${xen_list} | tr ' ' '\n' | sed -e 's/\.old$/
1/; / 1$/! s/$/ 2/' | version_sort -r | sed -e 's/ 1$/.old/; s/ 2$//')
+reverse_sorted_linux_list=$(echo ${linux_list} | tr ' ' '\n' | sed -e
's/\.old$/ 1/; / 1$/! s/$/ 2/' | version_sort -r | sed -e 's/ 1$/.old/; s/
2$//')
+
is_top_level=true
-while [ "x${xen_list}" != "x" ] ; do
- list="${linux_list}"
- current_xen=`version_find_latest $xen_list`
+for current_xen in ${reverse_sorted_xen_list}; do
xen_basename=`basename ${current_xen}`
xen_dirname=`dirname ${current_xen}`
rel_xen_dirname=`make_system_path_relative_to_its_root $xen_dirname`
@@ -273,8 +279,7 @@ while [ "x${xen_list}" != "x" ] ; do
fi
done
- while [ "x$list" != "x" ] ; do
- linux=`version_find_latest $list`
+ for linux in ${reverse_sorted_linux_list}; do
gettext_printf "Found linux image: %s\n" "$linux" >&2
basename=`basename $linux`
dirname=`dirname $linux`
@@ -351,13 +356,10 @@ while [ "x${xen_list}" != "x" ] ; do
linux_entry "${OS}" "${version}" "${xen_version}" recovery \
"${GRUB_CMDLINE_LINUX_RECOVERY} ${GRUB_CMDLINE_LINUX}"
"${GRUB_CMDLINE_XEN}"
fi
-
- list=`echo $list | tr ' ' '\n' | fgrep -vx "$linux" | tr '\n' ' '`
done
if [ x"$is_top_level" != xtrue ]; then
echo ' }'
fi
- xen_list=`echo $xen_list | tr ' ' '\n' | fgrep -vx "$current_xen" | tr
'\n' ' '`
done
# If at least one kernel was found, then we need to
--
2.30.2
- [PATCH v6 0/5] grub-mkconfig: Fix quadratic algorithm for sorting menu items, Mathieu Desnoyers, 2022/06/13
- [PATCH v6 2/5] grub-mkconfig linux_xen: Fix quadratic algorithm for sorting menu items,
Mathieu Desnoyers <=
- [PATCH v6 5/5] Cleanup: grub-mkconfig_lib: remove unused version comparison functions, Mathieu Desnoyers, 2022/06/13
- [PATCH v6 4/5] grub-mkconfig kfreebsd: Fix quadratic algorithm for sorting menu items, Mathieu Desnoyers, 2022/06/13
- [PATCH v6 1/5] grub-mkconfig linux: Fix quadratic algorithm for sorting menu items, Mathieu Desnoyers, 2022/06/13
- [PATCH v6 3/5] grub-mkconfig hurd: Fix quadratic algorithm for sorting menu items, Mathieu Desnoyers, 2022/06/13
- Re: [PATCH v6 0/5] grub-mkconfig: Fix quadratic algorithm for sorting menu items, Daniel Kiper, 2022/06/24