[v2,2/9] Kernel Memory cgroup

diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index ac663c1..363b8e8 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -35,6 +35,10 @@  SUBSYS(cpuacct)
 SUBSYS(mem_cgroup)
 #endif
 
+#ifdef CONFIG_CGROUP_KMEM
+SUBSYS(kmem)
+#endif
+
 /* */
 
 #ifdef CONFIG_CGROUP_DEVICE
diff --git a/include/linux/kmem_cgroup.h b/include/linux/kmem_cgroup.h
new file mode 100644
index 0000000..0e4a74b
--- /dev/null
+++ b/include/linux/kmem_cgroup.h
@@ -0,0 +1,53 @@ 
+/* kmem_cgroup.h - Kernel Memory Controller
+ *
+ * Copyright Parallels Inc., 2011
+ * Author: Glauber Costa <glommer@parallels.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _LINUX_KMEM_CGROUP_H
+#define _LINUX_KMEM_CGROUP_H
+#include <linux/cgroup.h>
+#include <linux/atomic.h>
+#include <linux/percpu_counter.h>
+
+struct kmem_cgroup {
+	struct cgroup_subsys_state css;
+	struct kmem_cgroup *parent;
+};
+
+
+#ifdef CONFIG_CGROUP_KMEM
+static inline struct kmem_cgroup *kcg_from_cgroup(struct cgroup *cgrp)
+{
+	return container_of(cgroup_subsys_state(cgrp, kmem_subsys_id),
+		struct kmem_cgroup, css);
+}
+
+static inline struct kmem_cgroup *kcg_from_task(struct task_struct *tsk)
+{
+	return container_of(task_subsys_state(tsk, kmem_subsys_id),
+		struct kmem_cgroup, css);
+}
+#else
+static inline struct kmem_cgroup *kcg_from_cgroup(struct cgroup *cgrp)
+{
+	return NULL;
+}
+
+static inline struct kmem_cgroup *kcg_from_task(struct task_struct *tsk)
+{
+	return NULL;
+}
+#endif /* CONFIG_CGROUP_KMEM */
+#endif /* _LINUX_KMEM_CGROUP_H */
+
diff --git a/init/Kconfig b/init/Kconfig
index d627783..5955ac2 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -690,6 +690,17 @@  config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
 	  select this option (if, for some reason, they need to disable it
 	  then swapaccount=0 does the trick).
 
+config CGROUP_KMEM
+	bool "Kernel Memory Resource Controller for Control Groups"
+	depends on CGROUPS
+	help
+	  The Kernel Memory cgroup can limit the amount of memory used by
+	  certain kernel objects in the system. Those are fundamentally
+	  different from the entities handled by the Memory Controller,
+	  which are page-based, and can be swapped. Users of the kmem
+	  cgroup can use it to guarantee that no group of processes will
+	  ever exhaust kernel resources alone.
+
 config CGROUP_PERF
 	bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 	depends on PERF_EVENTS && CGROUPS
diff --git a/mm/Makefile b/mm/Makefile
index 836e416..1b1aa24 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -45,6 +45,7 @@  obj-$(CONFIG_MIGRATION) += migrate.o
 obj-$(CONFIG_QUICKLIST) += quicklist.o
 obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o
 obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
+obj-$(CONFIG_CGROUP_KMEM) += kmem_cgroup.o
 obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
 obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
 obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
diff --git a/mm/kmem_cgroup.c b/mm/kmem_cgroup.c
new file mode 100644
index 0000000..7950e69
--- /dev/null
+++ b/mm/kmem_cgroup.c
@@ -0,0 +1,53 @@ 
+/* kmem_cgroup.c - Kernel Memory Controller
+ *
+ * Copyright Parallels Inc, 2011
+ * Author: Glauber Costa <glommer@parallels.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/cgroup.h>
+#include <linux/slab.h>
+#include <linux/kmem_cgroup.h>
+
+static int kmem_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+	return 0;
+}
+
+static void
+kmem_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+	struct kmem_cgroup *cg = kcg_from_cgroup(cgrp);
+	kfree(cg);
+}
+
+static struct cgroup_subsys_state *kmem_create(
+	struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+	struct kmem_cgroup *sk = kzalloc(sizeof(*sk), GFP_KERNEL);
+
+	if (!sk)
+		return ERR_PTR(-ENOMEM);
+
+	if (cgrp->parent)
+		sk->parent = kcg_from_cgroup(cgrp->parent);
+
+	return &sk->css;
+}
+
+struct cgroup_subsys kmem_subsys = {
+	.name = "kmem",
+	.create = kmem_create,
+	.destroy = kmem_destroy,
+	.populate = kmem_populate,
+	.subsys_id = kmem_subsys_id,
+};