Enabled with CONFIG_CGROUP_MEM_RES_CTLR_KMEM.

Adds the following files:
     - memory.kmem.independent_kmem_limit
     - memory.kmem.usage_in_bytes
     - memory.kmem.limit_in_bytes

Signed-off-by: Suleiman Souhlal<redacted>
---
  mm/memcontrol.c |  121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
  1 files changed, 120 insertions(+), 1 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 228d646..11e31d6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

@@ -235,6 +235,10 @@ struct mem_cgroup {
  	 */
  	struct res_counter memsw;
  	/*
+	 * the counter to account for kernel memory usage.
+	 */
+	struct res_counter kmem_bytes;
+	/*

  	 * Per cgroup active and inactive list, similar to the
  	 * per zone LRU lists.
  	 */

@@ -293,6 +297,7 @@ struct mem_cgroup {
  #ifdef CONFIG_INET
  	struct tcp_memcontrol tcp_mem;
  #endif
+	int independent_kmem_limit;
  };

  /* Stuffs for move charges at task migration. */

@@ -354,6 +359,7 @@ enum charge_type {
  #define _MEM			(0)
  #define _MEMSWAP		(1)
  #define _OOM_TYPE		(2)
+#define _KMEM			(3)
  #define MEMFILE_PRIVATE(x, val)	(((x)<<  16) | (val))
  #define MEMFILE_TYPE(val)	(((val)>>  16)&  0xffff)
  #define MEMFILE_ATTR(val)	((val)&  0xffff)

@@ -370,6 +376,8 @@ enum charge_type {

  static void mem_cgroup_get(struct mem_cgroup *memcg);
  static void mem_cgroup_put(struct mem_cgroup *memcg);
+static void memcg_kmem_init(struct mem_cgroup *memcg,
+    struct mem_cgroup *parent);

  /* Writing them here to avoid exposing memcg's inner layout */
  #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM

@@ -1402,6 +1410,10 @@ done:
  		res_counter_read_u64(&memcg->memsw, RES_USAGE)>>  10,
  		res_counter_read_u64(&memcg->memsw, RES_LIMIT)>>  10,
  		res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
+	printk(KERN_INFO "kmem: usage %llukB, limit %llukB, failcnt %llu\n",
+		res_counter_read_u64(&memcg->kmem_bytes, RES_USAGE)>>  10,
+		res_counter_read_u64(&memcg->kmem_bytes, RES_LIMIT)>>  10,
+		res_counter_read_u64(&memcg->kmem_bytes, RES_FAILCNT));
  }

  /*

@@ -3840,6 +3852,9 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
  		else
  			val = res_counter_read_u64(&memcg->memsw, name);
  		break;
+	case _KMEM:
+		val = res_counter_read_u64(&memcg->kmem_bytes, name);
+		break;
  	default:
  		BUG();
  		break;

@@ -3872,8 +3887,14 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
  			break;
  		if (type == _MEM)
  			ret = mem_cgroup_resize_limit(memcg, val);
-		else
+		else if (type == _MEMSWAP)
  			ret = mem_cgroup_resize_memsw_limit(memcg, val);
+		else if (type == _KMEM) {
+			if (!memcg->independent_kmem_limit)
+				return -EINVAL;
+			ret = res_counter_set_limit(&memcg->kmem_bytes, val);
+		} else
+			return -EINVAL;
  		break;
  	case RES_SOFT_LIMIT:
  		ret = res_counter_memparse_write_strategy(buffer,&val);

@@ -4572,8 +4593,47 @@ static int mem_control_numa_stat_open(struct inode *unused, struct file *file)
  #endif /* CONFIG_NUMA */

  #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+static u64
+mem_cgroup_independent_kmem_limit_read(struct cgroup *cgrp, struct cftype *cft)
+{
+	return mem_cgroup_from_cont(cgrp)->independent_kmem_limit;
+}
+
+static int mem_cgroup_independent_kmem_limit_write(struct cgroup *cgrp,
+    struct cftype *cft, u64 val)
+{
+	mem_cgroup_from_cont(cgrp)->independent_kmem_limit = !!val;
+
+	return 0;
+}
+
+static struct cftype kmem_cgroup_files[] = {
+	{
+		.name = "kmem.independent_kmem_limit",
+		.write_u64 = mem_cgroup_independent_kmem_limit_write,
+		.read_u64 = mem_cgroup_independent_kmem_limit_read,
+	},
+	{
+		.name = "kmem.limit_in_bytes",
+		.private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
+		.write_string = mem_cgroup_write,
+		.read_u64 = mem_cgroup_read,
+	},
+	{
+		.name = "kmem.usage_in_bytes",
+		.private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
+		.read_u64 = mem_cgroup_read,
+	},
+};
+
  static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss)
  {
+	int ret;
+
+	ret = cgroup_add_files(cont, ss, kmem_cgroup_files,
+	    ARRAY_SIZE(kmem_cgroup_files));
+	if (ret)
+		return ret;
  	/*
  	 * Part of this would be better living in a separate allocation
  	 * function, leaving us with just the cgroup tree population work.

@@ -4587,6 +4647,10 @@ static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss)
  static void kmem_cgroup_destroy(struct cgroup_subsys *ss,
  				struct cgroup *cont)
  {
+	struct mem_cgroup *memcg;
+
+	memcg = mem_cgroup_from_cont(cont);
+	BUG_ON(res_counter_read_u64(&memcg->kmem_bytes, RES_USAGE) != 0);