From edbb1cb3ce0c8bb83d0ebff085d25e758d46998b Mon Sep 17 00:00:00 2001
From: =?utf8?q?Jan=20Kr=C3=BCger?= <jk@jk.gs>
Date: Fri, 5 Nov 2010 04:10:40 +0100
Subject: [PATCH] jobd: properly skip unnecessary jobs
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Previously, jobs were skipped by having them execute /bin/false. That is
not only a waste of resources but can also cause annoying race
conditions if false exits more quickly than we can associate it with its
PID. Therefore, add a proper system for skipping jobs altogether and
include skipped jobs in progress output.

Signed-off-by: Jan Krüger <jk@jk.gs>
---
 jobd/jobd.pl | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/jobd/jobd.pl b/jobd/jobd.pl
index f0f55ad..2fd6eb6 100755
--- a/jobd/jobd.pl
+++ b/jobd/jobd.pl
@@ -87,6 +87,7 @@ my @running;
 my $perpetual = 1;
 my $locked = 0;
 my $jobs_executed;
+my $jobs_skipped;
 my @jobs_killed;
 
 sub handle_softexit {
@@ -125,6 +126,7 @@ sub handle_childgone {
 sub queue_job {
 	my %opts = @_;
 	$opts{'queued_at'} = time;
+	$opts{'dont_run'} = 0;
 	push @queue, \%opts;
 }
 
@@ -133,6 +135,11 @@ sub run_job {
 
 	push @running, $job;
 	$job->{'command'}->($job);
+	if ($job->{'dont_run'}) {
+		pop @running;
+		$jobs_skipped++;
+		return;
+	}
 }
 
 sub _job_name {
@@ -168,7 +175,7 @@ sub exec_job_command {
 
 sub job_skip {
 	my $job = shift;
-	exec_job_command($job, ['/bin/false']);
+	$job->{'dont_run'} = 1;
 }
 
 sub reap_hanging_jobs {
@@ -198,6 +205,7 @@ sub reap_finished_jobs {
 sub run_queue {
 	my $last_progress = time;
 	$jobs_executed = 0;
+	$jobs_skipped = 0;
 	@jobs_killed = ();
 	unless ($quiet) {
 		printf STDERR "--- Processing %d queued jobs\n", scalar(@queue);
@@ -212,7 +220,7 @@ sub run_queue {
 		if (@running >= $max_par) {
 			sleep 10;
 			unless (($quiet && !$progress) || (time - $last_progress) < 60) {
-				printf STDERR "STATUS: %d queued, %d running, %d finished, %d killed\n", scalar(@queue), scalar(@running), $jobs_executed, scalar(@jobs_killed);
+				printf STDERR "STATUS: %d queued, %d running, %d finished, %d skipped, %d killed\n", scalar(@queue), scalar(@running), $jobs_executed, $jobs_skipped, scalar(@jobs_killed);
 				if (@running) {
 					my @run_status;
 					for (@running) {
@@ -228,7 +236,7 @@ sub run_queue {
 		run_job(shift(@queue)) if @queue;
 	}
 	unless ($quiet) {
-		printf STDERR "--- Queue processed. %d jobs executed, %d killed due to timeouts. Now restarting.\n", $jobs_executed, scalar(@jobs_killed);
+		printf STDERR "--- Queue processed. %d jobs executed, %d skipped, %d killed. Now restarting.\n", $jobs_executed, $jobs_skipped, scalar(@jobs_killed);
 	}
 }
 
-- 
2.11.4.GIT