This patch creates a thread pool for memcg-kswapd. All memcg which needs
background recalim are linked to a list and memcg-kswapd picks up a memcg
from the list and run reclaim.
The concern of using per-memcg-kswapd thread is the system overhead including
memory and cputime.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Ying Han <yinghan@xxxxxxxxxx>
---
include/linux/memcontrol.h | 69 +++++++++++++++++++++++++++++++++++++
mm/memcontrol.c | 82 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 151 insertions(+), 0 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 3ece36d..9157c4d 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -84,6 +84,11 @@ extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
extern int mem_cgroup_watermark_ok(struct mem_cgroup *mem, int charge_flags);
+bool mem_cgroup_kswapd_can_sleep(void);
+struct mem_cgroup *mem_cgroup_get_shrink_target(void);
+void mem_cgroup_put_shrink_target(struct mem_cgroup *mem);
+wait_queue_head_t *mem_cgroup_kswapd_waitq(void);
+
static inline
int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
{
@@ -355,6 +360,70 @@ static inline void mem_cgroup_split_huge_fixup(struct page *head,
{
}
+/* background reclaim stats */
+static inline void mem_cgroup_kswapd_steal(struct mem_cgroup *memcg,
+ int val)
+{
+ return 0;
+}
+
+static inline void mem_cgroup_pg_steal(struct mem_cgroup *memcg,
+ int val)
+{
+ return 0;
+}
+
+static inline void mem_cgroup_kswapd_pgscan(struct mem_cgroup *memcg,
+ int val)
+{
+ return 0;
+}
+
+static inline void mem_cgroup_pg_pgscan(struct mem_cgroup *memcg,
+ int val)
+{
+ return 0;
+}
+
+static inline void mem_cgroup_pgrefill(struct mem_cgroup *memcg,
+ int val)
+{
+ return 0;
+}
+
+static inline void mem_cgroup_pg_outrun(struct mem_cgroup *memcg,
+ int val)
+{
+ return 0;
+}
+
+static inline void mem_cgroup_alloc_stall(struct mem_cgroup *memcg,
+ int val)
+{
+ return 0;
+}
+
+static inline bool mem_cgroup_kswapd_can_sleep(void)
+{
+ return false;
+}
+
+static inline
+struct mem_cgroup *mem_cgroup_get_shrink_target(void)
+{
+ return NULL;
+}
+
+static inline void mem_cgroup_put_shrink_target(struct mem_cgroup *mem)
+{
+}
+
+static inline
+wait_queue_head_t *mem_cgroup_kswapd_waitq(void)
+{
+ return NULL;
+}
+
#endif /* CONFIG_CGROUP_MEM_CONT */
#if !defined(CONFIG_CGROUP_MEM_RES_CTLR) || !defined(CONFIG_DEBUG_VM)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6029f1b..527ad9a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -49,6 +49,8 @@
#include <linux/cpu.h>
#include <linux/oom.h>
#include "internal.h"
+#include <linux/kthread.h>
+#include <linux/freezer.h>
#include <asm/uaccess.h>
@@ -262,6 +264,14 @@ struct mem_cgroup {
* mem_cgroup ? And what type of charges should we move ?
*/
unsigned long move_charge_at_immigrate;
+
+ /* !=0 if a kswapd runs */
+ atomic_t kswapd_running;
+ /* for waiting the end*/
+ wait_queue_head_t memcg_kswapd_end;
+ /* for shceduling */
+ struct list_head memcg_kswapd_wait_list;
+
/*
* percpu counter.
*/
@@ -4392,6 +4402,76 @@ static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
return 0;
}
+/*
+ * Controls for background memory reclam stuff.
+ */
+struct memcg_kswapd_work {
+ spinlock_t lock;
+ struct list_head list;
+ wait_queue_head_t waitq;
+};
+
+struct memcg_kswapd_work memcg_kswapd_control;
+
+static void memcg_kswapd_wait_end(struct mem_cgroup *mem)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&mem->memcg_kswapd_end, &wait, TASK_INTERRUPTIBLE);
+ if (atomic_read(&mem->kswapd_running))
+ schedule();
+ finish_wait(&mem->memcg_kswapd_end, &wait);
+}
+
+struct mem_cgroup *mem_cgroup_get_shrink_target(void)
+{
+ struct mem_cgroup *mem;
+
+ spin_lock(&memcg_kswapd_control.lock);
+ rcu_read_lock();
+ do {
+ mem = NULL;
+ if (!list_empty(&memcg_kswapd_control.list)) {
+ mem = list_entry(memcg_kswapd_control.list.next,
+ struct mem_cgroup,
+ memcg_kswapd_wait_list);
+ list_del_init(&mem->memcg_kswapd_wait_list);
+ }
+ } while (mem && !css_tryget(&mem->css));
+ if (mem)
+ atomic_inc(&mem->kswapd_running);
+ rcu_read_unlock();
+ spin_unlock(&memcg_kswapd_control.lock);
+ return mem;
+}
+
+void mem_cgroup_put_shrink_target(struct mem_cgroup *mem)
+{
+ if (!mem)
+ return;
+ atomic_dec(&mem->kswapd_running);
+ if (!mem_cgroup_watermark_ok(mem, CHARGE_WMARK_HIGH)) {
+ spin_lock(&memcg_kswapd_control.lock);
+ if (list_empty(&mem->memcg_kswapd_wait_list)) {
+ list_add_tail(&mem->memcg_kswapd_wait_list,
+ &memcg_kswapd_control.list);
+ }
+ spin_unlock(&memcg_kswapd_control.lock);
+ }
+ wake_up_all(&mem->memcg_kswapd_end);
+ cgroup_release_and_wakeup_rmdir(&mem->css);
+}
+
+bool mem_cgroup_kswapd_can_sleep(void)
+{
+ return list_empty(&memcg_kswapd_control.list);
+}
+
+wait_queue_head_t *mem_cgroup_kswapd_waitq(void)
+{
+ return &memcg_kswapd_control.waitq;
+}
+
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
@@ -4755,6 +4835,8 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
atomic_set(&mem->refcnt, 1);
mem->move_charge_at_immigrate = 0;
mutex_init(&mem->thresholds_lock);
+ init_waitqueue_head(&mem->memcg_kswapd_end);
+ INIT_LIST_HEAD(&mem->memcg_kswapd_wait_list);
return &mem->css;
free_out:
__mem_cgroup_free(mem);
--
1.7.3.1
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