Commit 1b5539b1 authored Sep 11, 2013 by Joe Perches Committed by Linus Torvalds Sep 11, 2013

checkpatch: reduce runtime/cpu time used



There are some cases where checkpatch can take a long time to complete.
Reduce the likelihood of this long run-time by adding a new test for lines
with and without comments and eliminating checks on lines with only
comments.

This reduces the number of "ctx_statement_block" calls, and also the
number of tests of $stat, which is now undefined for these blank lines.

One test in particular, the "check for switch/default statements without a
break", could take an extremely long time to parse as it tries to skip
interleaving comments within the ctx_statement_block/$stat and that could
be done multiple times unnecessarily.

A small test case taken from cfg80211.h before this patch would take
1000's of seconds to run, now it's just a couple seconds.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b34c648b

scripts/checkpatch.pl

+3 −1

Original line number	Diff line number	Diff line
		@@ -1678,6 +1678,8 @@ sub process {
		$linenr = 0;
		foreach my $line (@lines) {
		$linenr++;
		my $sline = $line; #copy of $line
		$sline =~ s/$;/ /g; #with comments as spaces

		my $rawline = $rawlines[$linenr - 1];

		@@ -2194,7 +2196,7 @@ sub process {
		$realline_next);
		#print "LINE<$line>\n";
		if ($linenr >= $suppress_statement &&
		$realcnt && $line =~ /.\s*\S/) {
		$realcnt && $sline =~ /.\s*\S/) {
		($stat, $cond, $line_nr_next, $remain_next, $off_next) =
		ctx_statement_block($linenr, $realcnt, 0);
		$stat =~ s/\n./\n /g;