From 25fd1667c186eb871a4b66f9866d6446e41f1bc2 Mon Sep 17 00:00:00 2001
From: Florian Forster <octo@collectd.org>
Date: Wed, 12 Sep 2012 18:55:08 +0200
Subject: [PATCH] swap plugin: Add the "ReportBytes" option.

When enabled, swap I/O is reported in bytes, not pages. Only valid for Linux.

This should fix Github issue #10.
---
 src/collectd.conf.in  |  4 ++++
 src/collectd.conf.pod | 17 +++++++++++++++++
 src/swap.c            | 41 ++++++++++++++++++++++++++++++++++++++---
 3 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/src/collectd.conf.in b/src/collectd.conf.in
index 21d0eb17..e508be7b 100644
--- a/src/collectd.conf.in
+++ b/src/collectd.conf.in
@@ -818,6 +818,10 @@ FQDNLookup   true
 #   </Host>
 #</Plugin>
 
+#<Plugin "swap">
+#	ReportBytes true
+#</Plugin>
+
 #<Plugin "table">
 #	<Table "/proc/slabinfo">
 #		Instance "slabinfo"
diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index 75f79429..f359e9a0 100644
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -4031,6 +4031,23 @@ Since the configuration of the C<snmp plugin> is a little more complicated than
 other plugins, its documentation has been moved to an own manpage,
 L<collectd-snmp(5)>. Please see there for details.
 
+=head2 Plugin C<swap>
+
+The C<swap plugin> reports the number of bytes currently swapped out and the
+amount of swap space available. The precise metrics being exported depends on
+your operating system.
+
+Options:
+
+=over 4
+
+=item B<ReportBytes> B<false>|B<true>
+
+When enabled, the I<swap I/O> is reported in bytes. When disabled, the default,
+I<swap I/O> is reported in pages. This option is available under Linux only.
+
+=back
+
 =head2 Plugin C<syslog>
 
 =over 4
diff --git a/src/swap.c b/src/swap.c
index 46ba6652..1a152c90 100644
--- a/src/swap.c
+++ b/src/swap.c
@@ -1,6 +1,6 @@
 /**
  * collectd - src/swap.c
- * Copyright (C) 2005-2009  Florian octo Forster
+ * Copyright (C) 2005-2012  Florian octo Forster
  * Copyright (C) 2009       Stefan Völkel
  * Copyright (C) 2009       Manuel Sanmartin
  *
@@ -68,7 +68,8 @@
 #define MAX(x,y) ((x) > (y) ? (x) : (y))
 
 #if KERNEL_LINUX
-/* No global variables */
+static derive_t pagesize;
+static _Bool report_bytes = 0;
 /* #endif KERNEL_LINUX */
 
 #elif HAVE_LIBKSTAT
@@ -102,10 +103,16 @@ static perfstat_memory_total_t pmemory;
 # error "No applicable input method."
 #endif /* HAVE_LIBSTATGRAB */
 
+static const char *config_keys[] =
+{
+	"ReportBytes"
+};
+static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
+
 static int swap_init (void)
 {
 #if KERNEL_LINUX
-	/* No init stuff */
+	pagesize = (derive_t) sysconf (_SC_PAGESIZE);
 /* #endif KERNEL_LINUX */
 
 #elif HAVE_LIBKSTAT
@@ -284,6 +291,12 @@ static int swap_read (void)
 				sstrerror (errno, errbuf, sizeof (errbuf)));
 	}
 
+	if (report_bytes)
+	{
+		swap_in  *= pagesize;
+		swap_out *= pagesize;
+	}
+
 	swap_submit ("used",   1024 * swap_used,   DS_TYPE_GAUGE);
 	swap_submit ("free",   1024 * swap_free,   DS_TYPE_GAUGE);
 	swap_submit ("cached", 1024 * swap_cached, DS_TYPE_GAUGE);
@@ -490,8 +503,30 @@ static int swap_read (void)
 	return (0);
 } /* int swap_read */
 
+static int swap_config (const char *key, const char *value)
+{
+	if (strcasecmp ("ReportBytes", key) == 0)
+	{
+#if KERNEL_LINUX
+		report_bytes = IS_TRUE (value) ? 1 : 0;
+#else
+		WARNING ("swap plugin: The \"ReportBytes\" option is only "
+				"valid under Linux. The option is going to "
+				"be ignored.");
+#endif
+	}
+	else
+	{
+		return (-1);
+	}
+
+	return (0);
+} /* int swap_config */
+
 void module_register (void)
 {
+	plugin_register_config ("swap", swap_config,
+			config_keys, config_keys_num);
 	plugin_register_init ("swap", swap_init);
 	plugin_register_read ("swap", swap_read);
 } /* void module_register */
-- 
2.11.0