internal/frontend: add cgoup memory info

Change-Id: Ifc8796ed232876a42ca1957283621815a7f53cdc
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/365659
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
diff --git a/internal/frontend/server.go b/internal/frontend/server.go
index c64e59f..63945fe 100644
--- a/internal/frontend/server.go
+++ b/internal/frontend/server.go
@@ -246,6 +246,14 @@
 		memrow("Process RSS", pm.RSS)
 		memrow("System Total", sm.Total)
 		memrow("System Used", sm.Used)
+		cm, err := memory.ReadCgroupStats()
+		if err != nil {
+			row("CGroup Stats", "unavailable")
+		} else {
+			for k, v := range cm {
+				memrow("CGroup "+k, v)
+			}
+		}
 		fmt.Fprintf(w, "</table>\n")
 
 		fmt.Fprintf(w, "</body></html>\n")