Create a daemon which does background page reclaim.
This daemon
* starts when usage > high_watermark
* stops when usage < low_watermark.
Because kthread_run() cannot be used when init_mem_cgroup is initialized(Sigh),
thread for init_mem_cgroup is invoked later by initcall.
Changes from YAMAMOTO-san's version
* use kthread instead of workqueue.
Signed-off-by: KAMEZAWA Hiroyuki <[EMAIL PROTECTED]>
From: YAMAMOTO Takashi <[EMAIL PROTECTED]>
mm/memcontrol.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 79 insertions(+)
Index: linux-2.6.24-rc3-mm1/mm/memcontrol.c
===================================================================
--- linux-2.6.24-rc3-mm1.orig/mm/memcontrol.c 2007-11-28 16:44:57.000000000
+0900
+++ linux-2.6.24-rc3-mm1/mm/memcontrol.c 2007-11-28 17:21:57.000000000
+0900
@@ -30,6 +30,8 @@
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
#include <asm/uaccess.h>
@@ -122,6 +124,13 @@
*/
struct res_counter res;
/*
+ * background reclaim
+ */
+ struct {
+ wait_queue_head_t waitq;
+ struct task_struct *thread;
+ } daemon;
+ /*
* Per cgroup active and inactive list, similar to the
* per zone LRU lists.
*/
@@ -401,6 +410,17 @@
}
}
+static void
+mem_cgroup_schedule_reclaim(struct mem_cgroup *mem)
+{
+ if (!unlikely(mem->daemon.thread))
+ return;
+ if (!waitqueue_active(&mem->daemon.waitq))
+ return;
+ wake_up_interruptible(&mem->daemon.waitq);
+}
+
+
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
int ret;
@@ -677,6 +697,8 @@
mem_cgroup_out_of_memory(mem, GFP_KERNEL);
goto free_pc;
}
+ if (res_counter_above_high_watermark(&mem->res))
+ mem_cgroup_schedule_reclaim(mem);
atomic_set(&pc->ref_cnt, 1);
pc->mem_cgroup = mem;
@@ -832,6 +854,38 @@
}
/*
+ * Background page reclaim daeom for memory controller.
+ */
+
+static int mem_cgroup_reclaim_daemon(void *data)
+{
+ DEFINE_WAIT(wait);
+ struct mem_cgroup *mem = data;
+
+ css_get(&mem->css);
+ set_freezable();
+
+ while (!kthread_should_stop()) {
+ prepare_to_wait(&mem->daemon.waitq, &wait, TASK_INTERRUPTIBLE);
+
+ if (res_counter_below_low_watermark(&mem->res)) {
+ if (!kthread_should_stop()) {
+ schedule();
+ try_to_freeze();
+ }
+ finish_wait(&mem->daemon.waitq, &wait);
+ continue;
+ }
+ finish_wait(&mem->daemon.waitq, &wait);
+ try_to_free_mem_cgroup_pages(mem, GFP_HIGHUSER_MOVABLE);
+ }
+
+ css_put(&mem->css);
+
+ return 0;
+}
+
+/*
* This routine traverse page_cgroup in given list and drop them all.
* This routine ignores page_cgroup->ref_cnt.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
@@ -1045,6 +1100,7 @@
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
int ret;
+
ret = mem_cgroup_force_empty(mem);
if (!ret)
ret = nbytes;
@@ -1188,6 +1244,16 @@
static struct mem_cgroup init_mem_cgroup;
+static int __init mem_cgroup_reclaim_init(void)
+{
+ init_mem_cgroup.daemon.thread = kthread_run(mem_cgroup_reclaim_daemon,
+ &init_mem_cgroup, "memcontd");
+ if (IS_ERR(init_mem_cgroup.daemon.thread))
+ BUG();
+ return 0;
+}
+late_initcall(mem_cgroup_reclaim_init);
+
static struct cgroup_subsys_state *
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
@@ -1212,6 +1278,17 @@
if (alloc_mem_cgroup_per_zone_info(mem, node))
goto free_out;
+ /* Memory Reclaim Daemon per cgroup */
+ init_waitqueue_head(&mem->daemon.waitq);
+ if (mem != &init_mem_cgroup) {
+ /* Complicated...but we cannot call kthread create here..*/
+ /* init call will later assign kthread */
+ mem->daemon.thread = kthread_run(mem_cgroup_reclaim_daemon,
+ mem, "memcontd");
+ if (IS_ERR(mem->daemon.thread))
+ goto free_out;
+ }
+
return &mem->css;
free_out:
for_each_node_state(node, N_POSSIBLE)
@@ -1226,6 +1303,7 @@
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
mem_cgroup_force_empty(mem);
+ kthread_stop(mem->daemon.thread);
}
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
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