From 415dda2945f5d31057b95bc343f7cda210b0c17b Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@sbcglobal.net>
Date: Thu, 26 Jan 2017 00:29:07 -0500
Subject: add cgswap

---
 .gitignore |  1 +
 Makefile   |  1 +
 cgswap.go  | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 99 insertions(+)
 create mode 100644 cgswap.go

diff --git a/.gitignore b/.gitignore
index e1a11d6..542d8a5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 *~
 batterymon
+cgswap
 chardiff
 chardiff_pre
 chardiff_post
diff --git a/Makefile b/Makefile
index 34bfc9d..945b903 100644
--- a/Makefile
+++ b/Makefile
@@ -10,6 +10,7 @@ GOBUILD = go build
 
 BINFILES = \
   batterymon \
+  cgswap \
   chardiff \
   chardiff_pre \
   chardiff_post \
diff --git a/cgswap.go b/cgswap.go
new file mode 100644
index 0000000..3491f17
--- /dev/null
+++ b/cgswap.go
@@ -0,0 +1,97 @@
+package main
+
+import (
+	"sync"
+	"fmt"
+	"os"
+	"bufio"
+	"strings"
+	"strconv"
+)
+
+func handleErr(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+type pidinfo struct {
+	VmSwap int
+	Cgroup string
+}
+
+func in_array(needle string, haystack []string) bool {
+	for _, straw := range haystack {
+		if needle == straw {
+			return true
+		}
+	}
+	return false
+}
+
+func main() {
+	dir, err := os.Open("/proc")
+	handleErr(err)
+	fileinfos, err := dir.Readdir(-1)
+	handleErr(err)
+
+	ch := make(chan pidinfo)
+	dat := make(map[string]int)
+	var consumers sync.WaitGroup
+	consumers.Add(1)
+	go func() {
+		for info := range ch {
+			cur, _ := dat[info.Cgroup]
+			dat[info.Cgroup] = cur + info.VmSwap
+		}
+		consumers.Done()
+	}()
+
+	var producers sync.WaitGroup
+	for _, fileinfo := range fileinfos {
+		if pid, err := strconv.Atoi(fileinfo.Name()); fileinfo.IsDir() && err == nil {
+			producers.Add(1)
+			go func(pid int) {
+				defer producers.Done()
+				statusFile, err := os.Open(fmt.Sprintf("/proc/%d/status", pid))
+				if err != nil {
+					return
+				}
+				cgroupFile, err := os.Open(fmt.Sprintf("/proc/%d/cgroup", pid))
+
+				buf := bufio.NewScanner(statusFile)
+				for buf.Scan() {
+					line := buf.Text()
+					if strings.HasPrefix(line, "VmSwap:") {
+						swap, err := strconv.Atoi(strings.TrimSpace(strings.TrimSuffix(strings.TrimPrefix(line, "VmSwap:"), "kB")))
+						if err != nil || swap == 0 {
+							return
+						}
+						buf := bufio.NewScanner(cgroupFile)
+						for buf.Scan() {
+							parts := strings.SplitN(buf.Text(), ":", 3)
+							if len(parts) != 3 {
+								continue
+							}
+							heir := parts[0]
+							controllers := strings.Split(parts[1], ",")
+							cgroup := parts[2]
+							if heir == "0" || in_array("name=systemd", controllers) {
+								ch <- pidinfo{VmSwap: swap, Cgroup: cgroup}
+								return
+							}
+						}
+						return
+					}
+				}
+			}(pid)
+		}
+	}
+	producers.Wait()
+	close(ch)
+	consumers.Wait()
+	for cgroup, vmswap := range dat {
+		fmt.Println(vmswap, "kB", cgroup)
+	}
+}
+//	grep VmSwap /proc/*/status|sed -rn 's|^/proc/([0-9]+)/status:VmSwap:\s*(\S+ \S+)$|\2 \1|p'|while read -r kb _ pid; do echo "$kb $(systemctl status "$pid"|head -n1|awk '{print $2}')"; done
-- 
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