[Devel] [PATCH] memory.swappiness

[YAMAMOTO Takashi]

here's a trivial patch to implement memory.swappiness,
which controls swappiness for cgroup memory reclamation.

it's against 2.6.24-rc3-mm2.

YAMAMOTO Takashi


Signed-off-by: YAMAMOTO Takashi <yamamoto at valinux.co.jp>
---

--- linux-2.6.24-rc3-mm2-swappiness/include/linux/memcontrol.h.BACKUP	2007-12-03 11:49:27.176669111 +0900
+++ linux-2.6.24-rc3-mm2-swappiness/include/linux/memcontrol.h	2007-12-03 10:00:29.049448425 +0900
@@ -46,6 +46,7 @@ extern void mem_cgroup_out_of_memory(str
 extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
 					gfp_t gfp_mask);
 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
+extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
 
 static inline struct mem_cgroup *mm_cgroup(const struct mm_struct *mm)
 {
--- linux-2.6.24-rc3-mm2-swappiness/mm/vmscan.c.BACKUP	2007-12-03 07:49:00.000000000 +0900
+++ linux-2.6.24-rc3-mm2-swappiness/mm/vmscan.c	2007-12-03 10:01:57.559803379 +0900
@@ -1030,7 +1030,7 @@ static int calc_reclaim_mapped(struct sc
 	 *
 	 * Max temporary value is vm_total_pages*100.
 	 */
-	imbalance *= (vm_swappiness + 1);
+	imbalance *= (sc->swappiness + 1);
 	imbalance /= 100;
 
 	/*
@@ -1445,7 +1445,7 @@ unsigned long try_to_free_mem_cgroup_pag
 		.may_writepage = !laptop_mode,
 		.may_swap = 1,
 		.swap_cluster_max = SWAP_CLUSTER_MAX,
-		.swappiness = vm_swappiness,
+		.swappiness = mem_cgroup_swappiness(mem_cont),
 		.order = 0,
 		.mem_cgroup = mem_cont,
 		.isolate_pages = mem_cgroup_isolate_pages,
--- linux-2.6.24-rc3-mm2-swappiness/mm/memcontrol.c.BACKUP	2007-12-03 07:49:00.000000000 +0900
+++ linux-2.6.24-rc3-mm2-swappiness/mm/memcontrol.c	2007-12-03 11:22:40.157163781 +0900
@@ -133,6 +133,7 @@ struct mem_cgroup {
 
 	unsigned long control_type;	/* control RSS or RSS+Pagecache */
 	int	prev_priority;	/* for recording reclaim priority */
+	unsigned int swappiness;	/* swappiness */
 	/*
 	 * statistics.
 	 */
@@ -1077,7 +1078,23 @@ static int mem_control_stat_open(struct 
 	return single_open(file, mem_control_stat_show, cont);
 }
 
+static int mem_cgroup_swappiness_write(struct cgroup *cont, struct cftype *cft,
+				       u64 val)
+{
+	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+
+	if (val > 100)
+		return -EINVAL;
+	mem->swappiness = val;
+	return 0;
+}
+
+static u64 mem_cgroup_swappiness_read(struct cgroup *cont, struct cftype *cft)
+{
+	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
 
+	return mem->swappiness;
+}
 
 static struct cftype mem_cgroup_files[] = {
 	{
@@ -1110,8 +1127,21 @@ static struct cftype mem_cgroup_files[] 
 		.name = "stat",
 		.open = mem_control_stat_open,
 	},
+	{
+		.name = "swappiness",
+		.write_uint = mem_cgroup_swappiness_write,
+		.read_uint = mem_cgroup_swappiness_read,
+	},
 };
 
+/* XXX probably it's better to move try_to_free_mem_cgroup_pages to
+  memcontrol.c and kill this */
+int mem_cgroup_swappiness(struct mem_cgroup *mem)
+{
+
+	return mem->swappiness;
+}
+
 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 {
 	struct mem_cgroup_per_node *pn;
@@ -1155,6 +1185,8 @@ mem_cgroup_create(struct cgroup_subsys *
 	res_counter_init(&mem->res);
 
 	mem->control_type = MEM_CGROUP_TYPE_ALL;
+	mem->swappiness = 60; /* XXX probably should inherit a value from
+				either parent cgroup or global vm_swappiness */
 	memset(&mem->info, 0, sizeof(mem->info));
 
 	for_each_node_state(node, N_POSSIBLE)
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