buddyinfo: Add support for /proc/buddyinfo for linux free memory fragmentation.

AUTHORS.md

@@ -35,5 +35,6 @@ The following individuals have contributed code to this repository
 * Siavash Safi <siavash.safi@gmail.com>
 * Stephen Shirley <kormat@gmail.com>
 * Steve Durrheimer <s.durrheimer@gmail.com>
+* Thorhallur Sverrisson <toti@toti.is>
 * Tobias Schmidt <tobidt@gmail.com>
 * Will Rouesnel <w.rouesnel@gmail.com>

README.md

@@ -47,6 +47,7 @@ zfs | Exposes [ZFS](http://open-zfs.org/) performance statistics. | [Linux](http
 Name     | Description | OS
 ---------|-------------|----
 bonding | Exposes the number of configured and active slaves of Linux bonding interfaces. | Linux
+buddyinfo | Exposes statistics of memory fragments as reported by /proc/buddyinfo. | Linux
 devstat | Exposes device statistics | Dragonfly, FreeBSD
 drbd | Exposes Distributed Replicated Block Device statistics | Linux
 interrupts | Exposes detailed interrupts statistics. | Linux, OpenBSD

collector/buddyinfo.go

@@ -0,0 +1,74 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !nobuddyinfo
+// +build !windows,!netbsd
+
+package collector
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/log"
+	"github.com/prometheus/procfs"
+)
+
+const (
+	buddyInfoSubsystem = "buddyinfo"
+)
+
+type buddyinfoCollector struct {
+	desc *prometheus.Desc
+}
+
+func init() {
+	Factories["buddyinfo"] = NewBuddyinfoCollector
+}
+
+// NewBuddyinfoCollector returns a new Collector exposing buddyinfo stats.
+func NewBuddyinfoCollector() (Collector, error) {
+	desc := prometheus.NewDesc(
+		prometheus.BuildFQName(Namespace, buddyInfoSubsystem, "count"),
+		"Count of free blocks according to size.",
+		[]string{"node", "zone", "size"}, nil,
+	)
+	return &buddyinfoCollector{desc}, nil
+}
+
+// Update calls (*buddyinfoCollector).getBuddyInfo to get the platform specific
+// buddyinfo metrics.
+func (c *buddyinfoCollector) Update(ch chan<- prometheus.Metric) (err error) {
+	fs, err := procfs.NewFS(*procPath)
+	if err != nil {
+		return fmt.Errorf("failed to open procfs: %v", err)
+	}
+
+	buddyInfo, err := fs.NewBuddyInfo()
+	if err != nil {
+		return fmt.Errorf("couldn't get buddyinfo: %s", err)
+	}
+
+	log.Debugf("Set node_buddy: %#v", buddyInfo)
+	for _, entry := range buddyInfo {
+		for size, value := range entry.Sizes {
+			ch <- prometheus.MustNewConstMetric(
+				c.desc,
+				prometheus.GaugeValue, value,
+				entry.Node, entry.Zone, strconv.Itoa(size),
+			)
+		}
+	}
+	return nil
+}

collector/fixtures/e2e-output.txt

@@ -82,6 +82,41 @@ node_bonding_slaves{master="int"} 2
 # HELP node_boot_time Node boot time, in unixtime.
 # TYPE node_boot_time gauge
 node_boot_time 1.418183276e+09
+# HELP node_buddyinfo_count Count of free blocks according to size.
+# TYPE node_buddyinfo_count gauge
+node_buddyinfo_count{node="0",size="0",zone="DMA"} 1
+node_buddyinfo_count{node="0",size="0",zone="DMA32"} 759
+node_buddyinfo_count{node="0",size="0",zone="Normal"} 4381
+node_buddyinfo_count{node="0",size="1",zone="DMA"} 0
+node_buddyinfo_count{node="0",size="1",zone="DMA32"} 572
+node_buddyinfo_count{node="0",size="1",zone="Normal"} 1093
+node_buddyinfo_count{node="0",size="10",zone="DMA"} 3
+node_buddyinfo_count{node="0",size="10",zone="DMA32"} 0
+node_buddyinfo_count{node="0",size="10",zone="Normal"} 0
+node_buddyinfo_count{node="0",size="2",zone="DMA"} 1
+node_buddyinfo_count{node="0",size="2",zone="DMA32"} 791
+node_buddyinfo_count{node="0",size="2",zone="Normal"} 185
+node_buddyinfo_count{node="0",size="3",zone="DMA"} 0
+node_buddyinfo_count{node="0",size="3",zone="DMA32"} 475
+node_buddyinfo_count{node="0",size="3",zone="Normal"} 1530
+node_buddyinfo_count{node="0",size="4",zone="DMA"} 2
+node_buddyinfo_count{node="0",size="4",zone="DMA32"} 194
+node_buddyinfo_count{node="0",size="4",zone="Normal"} 567
+node_buddyinfo_count{node="0",size="5",zone="DMA"} 1
+node_buddyinfo_count{node="0",size="5",zone="DMA32"} 45
+node_buddyinfo_count{node="0",size="5",zone="Normal"} 102
+node_buddyinfo_count{node="0",size="6",zone="DMA"} 1
+node_buddyinfo_count{node="0",size="6",zone="DMA32"} 12
+node_buddyinfo_count{node="0",size="6",zone="Normal"} 4
+node_buddyinfo_count{node="0",size="7",zone="DMA"} 0
+node_buddyinfo_count{node="0",size="7",zone="DMA32"} 0
+node_buddyinfo_count{node="0",size="7",zone="Normal"} 0
+node_buddyinfo_count{node="0",size="8",zone="DMA"} 1
+node_buddyinfo_count{node="0",size="8",zone="DMA32"} 0
+node_buddyinfo_count{node="0",size="8",zone="Normal"} 0
+node_buddyinfo_count{node="0",size="9",zone="DMA"} 1
+node_buddyinfo_count{node="0",size="9",zone="DMA32"} 0
+node_buddyinfo_count{node="0",size="9",zone="Normal"} 0
 # HELP node_context_switches Total number of context switches.
 # TYPE node_context_switches counter
 node_context_switches 3.8014093e+07

collector/fixtures/proc/buddyinfo

@@ -0,0 +1,3 @@
+Node 0, zone      DMA      1      0      1      0      2      1      1      0      1      1      3 
+Node 0, zone    DMA32    759    572    791    475    194     45     12      0      0      0      0 
+Node 0, zone   Normal   4381   1093    185   1530    567    102      4      0      0      0      0 

end-to-end-test.sh

@@ -3,6 +3,7 @@
 set -euf -o pipefail
 
 collectors=$(cat << COLLECTORS
+  buddyinfo
   conntrack
   diskstats
   drbd