From 676be0c5f86e71c7e3532e6315d5852d2627e637 Mon Sep 17 00:00:00 2001
From: Qiang Huang <h.huangqiang@huawei.com>
Date: Fri, 15 May 2015 14:24:56 +0800
Subject: [PATCH] Add support for kmem limit

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
---
 cgroups/fs/memory.go             |  5 +++++
 cgroups/fs/memory_test.go        | 28 +++++++++++++++++++++++
 cgroups/systemd/apply_systemd.go | 38 ++++++++++++++++++++------------
 configs/cgroup.go                |  3 +++
 4 files changed, 60 insertions(+), 14 deletions(-)

diff --git a/cgroups/fs/memory.go b/cgroups/fs/memory.go
index 2dcef0f4..744297b7 100644
--- a/cgroups/fs/memory.go
+++ b/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 {
diff --git a/cgroups/fs/memory_test.go b/cgroups/fs/memory_test.go
index 60edc67a..2dd50bd1 100644
--- a/cgroups/fs/memory_test.go
+++ b/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()
diff --git a/cgroups/systemd/apply_systemd.go b/cgroups/systemd/apply_systemd.go
index 27c11e18..66919816 100644
--- a/cgroups/systemd/apply_systemd.go
+++ b/cgroups/systemd/apply_systemd.go
@@ -200,12 +200,8 @@ 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
-		}
-
+	if err := joinMemory(c, pid); err != nil {
+		return err
 	}
 
 	// we need to manually join the freezer, net_prio and cpuset cgroup in systemd
@@ -435,19 +431,33 @@ func joinDevices(c *configs.Cgroup, pid int) error {
 }
 
 func joinMemory(c *configs.Cgroup, pid int) error {
-	memorySwap := c.MemorySwap
-
-	if memorySwap == 0 {
-		// By default, MemorySwap is set to twice the size of RAM.
-		memorySwap = c.Memory * 2
-	}
-
 	path, err := getSubsystemPath(c, "memory")
 	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
 
-	return writeFile(path, "memory.memsw.limit_in_bytes", strconv.FormatInt(memorySwap, 10))
+	// -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))
+		if err != nil {
+			return err
+		}
+	}
+
+	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
diff --git a/configs/cgroup.go b/configs/cgroup.go
index 8701de3f..da701291 100644
--- a/configs/cgroup.go
+++ b/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"`