ktest: Sort make_min_config configs by dependecies

The make_min_config test will turn off one config at a time and check
if the config boots or not, and if it does, it will remove that config
plus any config that depended on that config.

ktest already looks if a config has a dependency and will try the
dependency config first. But by sorting the configs and trying the
config with the most configs dependent on it, we can shrink the
minconfig faster.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

tools/testing/ktest/ktest.pl

@@ -2372,12 +2372,31 @@ sub patchcheck {
 }
 
 my %depends;
+my %depcount;
 my $iflevel = 0;
 my @ifdeps;
 
 # prevent recursion
 my %read_kconfigs;
 
+sub add_dep {
+    # $config depends on $dep
+    my ($config, $dep) = @_;
+
+    if (defined($depends{$config})) {
+	$depends{$config} .= " " . $dep;
+    } else {
+	$depends{$config} = $dep;
+    }
+
+    # record the number of configs depending on $dep
+    if (defined $depcount{$dep}) {
+	$depcount{$dep}++;
+    } else {
+	$depcount{$dep} = 1;
+    } 
+}
+
 # taken from streamline_config.pl
 sub read_kconfig {
     my ($kconfig) = @_;
@@ -2424,30 +2443,19 @@ sub read_kconfig {
 	    $config = $2;
 
 	    for (my $i = 0; $i < $iflevel; $i++) {
-		if ($i) {
-		    $depends{$config} .= " " . $ifdeps[$i];
-		} else {
-		    $depends{$config} = $ifdeps[$i];
-		}
-		$state = "DEP";
+		add_dep $config, $ifdeps[$i];
 	    }
 
 	# collect the depends for the config
 	} elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) {
 
-	    if (defined($depends{$1})) {
-		$depends{$config} .= " " . $1;
-	    } else {
-		$depends{$config} = $1;
-	    }
+	    add_dep $config, $1;
 
 	# Get the configs that select this config
-	} elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
-	    if (defined($depends{$1})) {
-		$depends{$1} .= " " . $config;
-	    } else {
-		$depends{$1} = $config;
-	    }
+	} elsif ($state eq "NEW" && /^\s*select\s+(\S+)/) {
+
+	    # selected by depends on config
+	    add_dep $1, $config;
 
 	# Check for if statements
 	} elsif (/^if\s+(.*\S)\s*$/) {
@@ -2559,11 +2567,18 @@ sub make_new_config {
     close OUT;
 }
 
+sub chomp_config {
+    my ($config) = @_;
+
+    $config =~ s/CONFIG_//;
+
+    return $config;
+}
+
 sub get_depends {
     my ($dep) = @_;
 
-    my $kconfig = $dep;
-    $kconfig =~ s/CONFIG_//;
+    my $kconfig = chomp_config $dep;
 
     $dep = $depends{"$kconfig"};
 
@@ -2613,8 +2628,7 @@ sub test_this_config {
 	return undef;
     }
 
-    my $kconfig = $config;
-    $kconfig =~ s/CONFIG_//;
+    my $kconfig = chomp_config $config;
 
     # Test dependencies first
     if (defined($depends{"$kconfig"})) {
@@ -2704,6 +2718,14 @@ sub make_min_config {
 
     my @config_keys = keys %min_configs;
 
+    # All configs need a depcount
+    foreach my $config (@config_keys) {
+	my $kconfig = chomp_config $config;
+	if (!defined $depcount{$kconfig}) {
+		$depcount{$kconfig} = 0;
+	}
+    }
+
     # Remove anything that was set by the make allnoconfig
     # we shouldn't need them as they get set for us anyway.
     foreach my $config (@config_keys) {
@@ -2742,8 +2764,13 @@ sub make_min_config {
 	# Now disable each config one by one and do a make oldconfig
 	# till we find a config that changes our list.
 
-	# Put configs that did not modify the config at the end.
 	my @test_configs = keys %min_configs;
+
+	# Sort keys by who is most dependent on
+	@test_configs = sort  { $depcount{chomp_config($b)} <=> $depcount{chomp_config($a)} }
+			  @test_configs ;
+
+	# Put configs that did not modify the config at the end.
 	my $reset = 1;
 	for (my $i = 0; $i < $#test_configs; $i++) {
 	    if (!defined($nochange_config{$test_configs[0]})) {