[patch 45/86] checkpatch: reduce is_maintained_obsolete lookup runtime

Andrew Morton
2019-12-05T00:52:12Z

From: Joe Perches <joe@perches.com>
Subject: checkpatch: reduce is_maintained_obsolete lookup runtime

The is_maintained_obsolete function can be called twice using the same
filename. This function spawns a process using get_maintainer.pl. Store
the status of each filename when spawned and use the stored result to
eliminate the spawning of unnecessary duplicate child processes.

Example:

old:

$ time ./scripts/checkpatch.pl hp100-Move-to-staging.patch > /dev/null

real 0m1.767s
user 0m1.634s
sys 0m0.141s

new:

$ time ./scripts/checkpatch.pl hp100-Move-to-staging.patch > /dev/null

real 0m1.184s
user 0m1.085s
sys 0m0.103s

Link: http://lkml.kernel.org/r/b982566a2b9b4825badce36fdfc3032bd0005151.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

scripts/checkpatch.pl | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/scripts/checkpatch.pl~checkpatch-reduce-is_maintained_obsolete-lookup-runtime
+++ a/scripts/checkpatch.pl
@@ -874,14 +874,18 @@ sub seed_camelcase_file {
}
}

+our %maintained_status = ();
+
sub is_maintained_obsolete {
my ($filename) = @_;

return 0 if (!$tree || !(-e "$root/scripts/get_maintainer.pl"));

- my $status = `perl $root/scripts/get_maintainer.pl --status --nom --nol --nogit --nogit-fallback -f $filename 2>&1`;
+ if (!exists($maintained_status{$filename})) {
+ $maintained_status{$filename} = `perl $root/scripts/get_maintainer.pl --status --nom --nol --nogit --nogit-fallback -f $filename 2>&1`;
+ }

- return $status =~ /obsolete/i;
+ return $maintained_status{$filename} =~ /obsolete/i;
}

sub is_SPDX_License_valid {
_