Merge pull request #591 from hqhq/hq_add_kmemlimit

Add support for kmem limit

cgroups/fs/memory.go

@@ -54,6 +54,11 @@ func (s *MemoryGroup) Set(path string, cgroup *configs.Cgroup) error {
 			return err
 		}
 	}
+	if cgroup.KernelMemory > 0 {
+		if err := writeFile(path, "memory.kmem.limit_in_bytes", strconv.FormatInt(cgroup.KernelMemory, 10)); err != nil {
+			return err
+		}
+	}
 
 	if cgroup.OomKillDisable {
 		if err := writeFile(path, "memory.oom_control", "1"); err != nil {

cgroups/fs/memory_test.go

@@ -112,6 +112,34 @@ func TestMemorySetMemoryswapDefault(t *testing.T) {
 	}
 }
 
+func TestMemorySetKernelMemory(t *testing.T) {
+	helper := NewCgroupTestUtil("memory", t)
+	defer helper.cleanup()
+
+	const (
+		kernelMemoryBefore = 314572800 // 300M
+		kernelMemoryAfter  = 524288000 // 500M
+	)
+
+	helper.writeFileContents(map[string]string{
+		"memory.kmem.limit_in_bytes": strconv.Itoa(kernelMemoryBefore),
+	})
+
+	helper.CgroupData.c.KernelMemory = kernelMemoryAfter
+	memory := &MemoryGroup{}
+	if err := memory.Set(helper.CgroupPath, helper.CgroupData.c); err != nil {
+		t.Fatal(err)
+	}
+
+	value, err := getCgroupParamUint(helper.CgroupPath, "memory.kmem.limit_in_bytes")
+	if err != nil {
+		t.Fatalf("Failed to parse memory.kmem.limit_in_bytes - %s", err)
+	}
+	if value != kernelMemoryAfter {
+		t.Fatal("Got the wrong value, set memory.kmem.limit_in_bytes failed.")
+	}
+}
+
 func TestMemoryStats(t *testing.T) {
 	helper := NewCgroupTestUtil("memory", t)
 	defer helper.cleanup()

cgroups/systemd/apply_systemd.go

@@ -200,14 +200,10 @@ func (m *Manager) Apply(pid int) error {
 		return err
 	}
 
-	// -1 disables memorySwap
-	if c.MemorySwap >= 0 && c.Memory != 0 {
 	if err := joinMemory(c, pid); err != nil {
 		return err
 	}
 
-	}
-
 	// we need to manually join the freezer, net_prio and cpuset cgroup in systemd
 	// because it does not currently support it via the dbus api.
 	if err := joinFreezer(c, pid); err != nil {
@@ -435,19 +431,33 @@ func joinDevices(c *configs.Cgroup, pid int) error {
 }
 
 func joinMemory(c *configs.Cgroup, pid int) error {
+	path, err := getSubsystemPath(c, "memory")
+	if err != nil && !cgroups.IsNotFound(err) {
+		return err
+	}
+
+	// -1 disables memoryswap
+	if c.Memory != 0 && c.MemorySwap >= 0 {
 		memorySwap := c.MemorySwap
 
 		if memorySwap == 0 {
 			// By default, MemorySwap is set to twice the size of RAM.
 			memorySwap = c.Memory * 2
 		}
-
+		err = writeFile(path, "memory.memsw.limit_in_bytes", strconv.FormatInt(memorySwap, 10))
-	path, err := getSubsystemPath(c, "memory")
+		if err != nil {
-	if err != nil && !cgroups.IsNotFound(err) {
 			return err
 		}
+	}
 
-	return writeFile(path, "memory.memsw.limit_in_bytes", strconv.FormatInt(memorySwap, 10))
+	if c.KernelMemory > 0 {
+		err = writeFile(path, "memory.kmem.limit_in_bytes", strconv.FormatInt(c.KernelMemory, 10))
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
 // systemd does not atm set up the cpuset controller, so we must manually

configs/cgroup.go

@@ -30,6 +30,9 @@ type Cgroup struct {
 	// Total memory usage (memory + swap); set `-1' to disable swap
 	MemorySwap int64 `json:"memory_swap"`
 
+	// Kernel memory limit (in bytes)
+	KernelMemory int64 `json:"kernel_memory"`
+
 	// CPU shares (relative weight vs. other containers)
 	CpuShares int64 `json:"cpu_shares"`