From 934119dc914a9e89a53ca714bc737be67a700a72 Mon Sep 17 00:00:00 2001
From: Sam Alba <sam.alba@gmail.com>
Date: Mon, 11 Mar 2013 17:40:54 -0700
Subject: [PATCH] Added support for RamSwap in the generated LXC config (to
 limit the swap and have the right default settings) Upstream-commit:
 75d04a5a7561cabba0aaf2875ef4479381096f91 Component: engine

---
 components/engine/container.go    |  3 ++-
 components/engine/lxc_template.go | 17 ++++++++++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/components/engine/container.go b/components/engine/container.go
index 530c08bc39..c837500549 100644
--- a/components/engine/container.go
+++ b/components/engine/container.go
@@ -53,7 +53,8 @@ type Container struct {
 type Config struct {
 	Hostname  string
 	User      string
-	Ram       int64
+	Ram       int64 // Memory limit (in bytes)
+	RamSwap   int64 // Total memory usage (ram + swap); set `-1' to disable swap
 	Ports     []int
 	Tty       bool // Attach standard streams to a tty, including stdin if it is not closed.
 	OpenStdin bool // Open stdin
diff --git a/components/engine/lxc_template.go b/components/engine/lxc_template.go
index 47f2058dc4..5a37624a32 100755
--- a/components/engine/lxc_template.go
+++ b/components/engine/lxc_template.go
@@ -88,14 +88,29 @@ lxc.cap.drop = audit_control audit_write mac_admin mac_override mknod net_raw se
 {{if .Config.Ram}}
 lxc.cgroup.memory.limit_in_bytes = {{.Config.Ram}}
 lxc.cgroup.memory.soft_limit_in_bytes = {{.Config.Ram}}
+{{with $ramSwap := getRamSwap .Config}}
+lxc.cgroup.memory.memsw.limit_in_bytes = {{$ramSwap}}
+{{end}}
 {{end}}
 `
 
 var LxcTemplateCompiled *template.Template
 
+func getRamSwap(config *Config) int64 {
+	// By default, RamSwap is set to twice the size of RAM.
+	// If you want to omit RamSwap, set it to `-1'.
+	if config.RamSwap < 0 {
+		return 0
+	}
+	return config.Ram * 2
+}
+
 func init() {
 	var err error
-	LxcTemplateCompiled, err = template.New("lxc").Parse(LxcTemplate)
+	funcMap := template.FuncMap{
+		"getRamSwap": getRamSwap,
+	}
+	LxcTemplateCompiled, err = template.New("lxc").Funcs(funcMap).Parse(LxcTemplate)
 	if err != nil {
 		panic(err)
 	}