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templates/linux_xen: Fix quadratic algorithm for sorting menu items

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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>
Cc: xen-devel@lists.xenproject.org
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Mathieu Desnoyers 2022-06-13 10:08:23 -04:00 committed by Daniel Kiper
parent 99e05ab555
commit 32d97497cb
1 changed files with 10 additions and 8 deletions
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18
util/grub.d/20_linux_xen.in
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@ -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