From bcfc527abba718dbf8b129344583eacc05090434 Mon Sep 17 00:00:00 2001
From: Victor Marmol <vmarmol@google.com>
Date: Thu, 24 Apr 2014 05:11:43 +0000
Subject: [PATCH] Separating cgroup Memory and MemoryReservation.

This will allow for these to be set independently. Keep the current Docker behavior where Memory and MemoryReservation are set to the value of Memory.

Docker-DCO-1.1-Signed-off-by: Victor Marmol <vmarmol@google.com> (github: vmarmol)
---
 cgroups/cgroups.go               | 15 ++++++++-------
 cgroups/fs/memory.go             |  9 ++++++---
 cgroups/systemd/apply_systemd.go |  4 ++++
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/cgroups/cgroups.go b/cgroups/cgroups.go
index 9a49860..81e3eb5 100644
--- a/cgroups/cgroups.go
+++ b/cgroups/cgroups.go
@@ -12,13 +12,14 @@ type Cgroup struct {
 	Name   string `json:"name,omitempty"`
 	Parent string `json:"parent,omitempty"`
 
-	DeviceAccess bool   `json:"device_access,omitempty"` // name of parent cgroup or slice
-	Memory       int64  `json:"memory,omitempty"`        // Memory limit (in bytes)
-	MemorySwap   int64  `json:"memory_swap,omitempty"`   // Total memory usage (memory + swap); set `-1' to disable swap
-	CpuShares    int64  `json:"cpu_shares,omitempty"`    // CPU shares (relative weight vs. other containers)
-	CpuQuota     int64  `json:"cpu_quota,omitempty"`     // CPU hardcap limit (in usecs). Allowed cpu time in a given period.
-	CpuPeriod    int64  `json:"cpu_period,omitempty"`    // CPU period to be used for hardcapping (in usecs). 0 to use system default.
-	CpusetCpus   string `json:"cpuset_cpus,omitempty"`   // CPU to use
+	DeviceAccess      bool   `json:"device_access,omitempty"`      // name of parent cgroup or slice
+	Memory            int64  `json:"memory,omitempty"`             // Memory limit (in bytes)
+	MemoryReservation int64  `json:"memory_reservation,omitempty"` // Memory reservation or soft_limit (in bytes)
+	MemorySwap        int64  `json:"memory_swap,omitempty"`        // Total memory usage (memory + swap); set `-1' to disable swap
+	CpuShares         int64  `json:"cpu_shares,omitempty"`         // CPU shares (relative weight vs. other containers)
+	CpuQuota          int64  `json:"cpu_quota,omitempty"`          // CPU hardcap limit (in usecs). Allowed cpu time in a given period.
+	CpuPeriod         int64  `json:"cpu_period,omitempty"`         // CPU period to be used for hardcapping (in usecs). 0 to use system default.
+	CpusetCpus        string `json:"cpuset_cpus,omitempty"`        // CPU to use
 
 	UnitProperties [][2]string `json:"unit_properties,omitempty"` // systemd unit properties
 }
diff --git a/cgroups/fs/memory.go b/cgroups/fs/memory.go
index cf4bf5a..5315291 100644
--- a/cgroups/fs/memory.go
+++ b/cgroups/fs/memory.go
@@ -13,7 +13,7 @@ type memoryGroup struct {
 func (s *memoryGroup) Set(d *data) error {
 	dir, err := d.join("memory")
 	// only return an error for memory if it was not specified
-	if err != nil && (d.c.Memory != 0 || d.c.MemorySwap != 0) {
+	if err != nil && (d.c.Memory != 0 || d.c.MemoryReservation != 0 || d.c.MemorySwap != 0) {
 		return err
 	}
 	defer func() {
@@ -22,12 +22,15 @@ func (s *memoryGroup) Set(d *data) error {
 		}
 	}()
 
-	if d.c.Memory != 0 || d.c.MemorySwap != 0 {
+	// Only set values if some config was specified.
+	if d.c.Memory != 0 || d.c.MemoryReservation != 0 || d.c.MemorySwap != 0 {
 		if d.c.Memory != 0 {
 			if err := writeFile(dir, "memory.limit_in_bytes", strconv.FormatInt(d.c.Memory, 10)); err != nil {
 				return err
 			}
-			if err := writeFile(dir, "memory.soft_limit_in_bytes", strconv.FormatInt(d.c.Memory, 10)); err != nil {
+		}
+		if d.c.MemoryReservation != 0 {
+			if err := writeFile(dir, "memory.soft_limit_in_bytes", strconv.FormatInt(d.c.MemoryReservation, 10)); err != nil {
 				return err
 			}
 		}
diff --git a/cgroups/systemd/apply_systemd.go b/cgroups/systemd/apply_systemd.go
index 7c26080..e1246f6 100644
--- a/cgroups/systemd/apply_systemd.go
+++ b/cgroups/systemd/apply_systemd.go
@@ -121,6 +121,10 @@ func Apply(c *cgroups.Cgroup, pid int) (cgroups.ActiveCgroup, error) {
 		properties = append(properties,
 			systemd1.Property{"MemoryLimit", dbus.MakeVariant(uint64(c.Memory))})
 	}
+	if c.MemoryReservation != 0 {
+		properties = append(properties,
+			systemd1.Property{"MemorySoftLimit", dbus.MakeVariant(uint64(c.MemoryReservation))})
+	}
 	// TODO: MemorySwap not available in systemd
 
 	if c.CpuShares != 0 {