[RFC][PATCH 1/3] Setup the kmem container

[Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>]

Attach the controller to the containers. This can work
with the SLUB allocator only. However, if we need I can
port this on SLAB (and even SLOB ;) ).

This setup is simple and stupid.

Signed-off-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

---

 include/linux/container_subsys.h |    4 +
 init/Kconfig                     |    6 ++
 mm/slub.c                        |  109 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 119 insertions(+)

diff --git a/include/linux/container_subsys.h b/include/linux/container_subsys.h
index 027465a..1dde0dc 100644
--- a/include/linux/container_subsys.h
+++ b/include/linux/container_subsys.h
@@ -29,4 +29,8 @@ SUBSYS(debug)
 SUBSYS(ns)
 #endif
 
+#ifdef CONFIG_CONTAINER_KMEM
+SUBSYS(kmem)
+#endif
+
 /* */
diff --git a/init/Kconfig b/init/Kconfig
index f9b8d14..4d071bc 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -364,6 +364,12 @@ config SYSFS_DEPRECATED
 	  If you are using a distro that was released in 2006 or later,
 	  it should be safe to say N here.
 
+config CONTAINER_KMEM
+	bool "Kernel memory controller for containers"
+	depends on CONTAINERS && RESOURCE_COUNTERS && SLUB
+	help
+	  Provedes a kernel memory usage controll for containers
+
 config PROC_PID_CPUSET
 	bool "Include legacy /proc/<pid>/cpuset file"
 	depends on CPUSETS
diff --git a/mm/slub.c b/mm/slub.c
index 130171d..e4f7390 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -21,6 +21,11 @@
 #include <linux/ctype.h>
 #include <linux/kallsyms.h>
 
+#ifdef CONFIG_CONTAINER_KMEM
+#include <linux/container.h>
+#include <linux/res_counter.h>
+#endif
+
 /*
  * Lock order:
  *   1. slab_lock(page)
@@ -3870,3 +4011,105 @@ static int __init slab_sysfs_init(void)
 
 __initcall(slab_sysfs_init);
 #endif
+
+#ifdef CONFIG_CONTAINER_KMEM
+struct kmem_container {
+	struct container_subsys_state css;
+	struct res_counter res;
+};
+
+static inline
+struct kmem_container *css_to_kmem(struct container_subsys_state *css)
+{
+	return container_of(css, struct kmem_container, css);
+}
+
+static inline 
+struct kmem_container *container_to_kmem(struct container *cont)
+{
+	return css_to_kmem(container_subsys_state(cont, kmem_subsys_id));
+}
+
+static inline
+struct kmem_container *task_kmem_container(struct task_struct *tsk)
+{
+	return css_to_kmem(task_subsys_state(tsk, kmem_subsys_id));
+}
+
+/*
+ * containers interface
+ */
+
+static struct kmem_container init_kmem_container;
+
+static struct container_subsys_state *kmem_create(struct container_subsys *ss,
+		struct container *container)
+{
+	struct kmem_container *mem;
+
+	if (unlikely((container->parent) == NULL))
+		mem = &init_kmem_container;
+	else
+		mem = kzalloc(sizeof(struct kmem_container), GFP_KERNEL);
+
+	if (mem == NULL)
+		return NULL;
+
+	res_counter_init(&mem->res);
+	return &mem->css;
+
+}
+
+static void kmem_destroy(struct container_subsys *ss,
+		struct container *container)
+{
+	kfree(container_to_kmem(container));
+}
+
+static ssize_t kmem_container_read(struct container *cont, struct cftype *cft,
+		struct file *file, char __user *userbuf, size_t nbytes,
+		loff_t *ppos)
+{
+	return res_counter_read(&container_to_kmem(cont)->res,
+			cft->private, userbuf, nbytes, ppos);
+}
+
+static ssize_t kmem_container_write(struct container *cont, struct cftype *cft,
+		struct file *file, const char __user *userbuf,
+		size_t nbytes, loff_t *ppos)
+{
+	return res_counter_write(&container_to_kmem(cont)->res,
+			cft->private, userbuf, nbytes, ppos);
+}
+
+static struct cftype kmem_files[] = {
+	{
+		.name = "usage",
+		.private = RES_USAGE,
+		.read = kmem_container_read,
+	},
+	{
+		.name = "limit",
+		.private = RES_LIMIT,
+		.write = kmem_container_write,
+		.read = kmem_container_read,
+	},
+	{
+		.name = "failcnt",
+		.private = RES_FAILCNT,
+		.read = kmem_container_read,
+	},
+};
+
+static int kmem_populate(struct container_subsys *ss, struct container *cnt)
+{
+	return container_add_files(cnt, ss, kmem_files, ARRAY_SIZE(kmem_files));
+}
+
+struct container_subsys kmem_subsys = {
+	.name = "kmem",
+	.create = kmem_create,
+	.destroy  = kmem_destroy,
+	.populate = kmem_populate,
+	.subsys_id = kmem_subsys_id,
+	.early_init = 1,
+};
+#endif