[PATCH 11/13] memcg: lazy LRU free (NEW)

KAMEZAWA Hiroyuki
2008-09-22T11:17:56Z

Free page_cgroup from its LRU in batched manner.

When uncharge() is called, page is pushed onto per-cpu vector and
removed from LRU, later.. This routine resembles to global LRU's pagevec.
This patch is half of the whole patch and a set with following lazy LRU add
patch.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

mm/memcontrol.c | 163 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 153 insertions(+), 10 deletions(-)

Index: mmotm-2.6.27-rc6+/mm/memcontrol.c
===================================================================
--- mmotm-2.6.27-rc6+.orig/mm/memcontrol.c
+++ mmotm-2.6.27-rc6+/mm/memcontrol.c
@@ -35,6 +35,7 @@
#include <linux/vmalloc.h>
#include <linux/mm_inline.h>
#include <linux/page_cgroup.h>
+#include <linux/cpu.h>

#include <asm/uaccess.h>

@@ -533,6 +534,116 @@ out:
return ret;
}

+
+#define MEMCG_PCPVEC_SIZE (14) /* size of pagevec */
+struct memcg_percpu_vec {
+ int nr;
+ int limit;
+ struct page_cgroup *vec[MEMCG_PCPVEC_SIZE];
+};
+static DEFINE_PER_CPU(struct memcg_percpu_vec, memcg_free_vec);
+
+static void
+__release_page_cgroup(struct memcg_percpu_vec *mpv)
+{
+ unsigned long flags;
+ struct mem_cgroup_per_zone *mz, *prev_mz;
+ struct page_cgroup *pc;
+ int i, nr;
+
+ local_irq_save(flags);
+ nr = mpv->nr;
+ mpv->nr = 0;
+ prev_mz = NULL;
+ for (i = nr - 1; i >= 0; i--) {
+ pc = mpv->vec[i];
+ VM_BUG_ON(PageCgroupUsed(pc));
+ mz = page_cgroup_zoneinfo(pc);
+ if (prev_mz != mz) {
+ if (prev_mz)
+ spin_unlock(&prev_mz->lru_lock);
+ prev_mz = mz;
+ spin_lock(&mz->lru_lock);
+ }
+ __mem_cgroup_remove_list(mz, pc);
+ css_put(&pc->mem_cgroup->css);
+ pc->mem_cgroup = NULL;
+ }
+ if (prev_mz)
+ spin_unlock(&prev_mz->lru_lock);
+ local_irq_restore(flags);
+
+}
+
+static void
+release_page_cgroup(struct page_cgroup *pc)
+{
+ struct memcg_percpu_vec *mpv;
+
+ mpv = &get_cpu_var(memcg_free_vec);
+ mpv->vec[mpv->nr++] = pc;
+ if (mpv->nr >= mpv->limit)
+ __release_page_cgroup(mpv);
+ put_cpu_var(memcg_free_vec);
+}
+
+static void page_cgroup_start_cache_cpu(int cpu)
+{
+ struct memcg_percpu_vec *mpv;
+ mpv = &per_cpu(memcg_free_vec, cpu);
+ mpv->limit = MEMCG_PCPVEC_SIZE;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void page_cgroup_stop_cache_cpu(int cpu)
+{
+ struct memcg_percpu_vec *mpv;
+ mpv = &per_cpu(memcg_free_vec, cpu);
+ mpv->limit = 0;
+}
+#endif
+
+
+/*
+ * Used when freeing memory resource controller to remove all
+ * page_cgroup (in obsolete list).
+ */
+static DEFINE_MUTEX(memcg_force_drain_mutex);
+
+static void drain_page_cgroup_local(struct work_struct *work)
+{
+ struct memcg_percpu_vec *mpv;
+ mpv = &get_cpu_var(memcg_free_vec);
+ __release_page_cgroup(mpv);
+ put_cpu_var(mpv);
+}
+
+static void drain_page_cgroup_cpu(int cpu)
+{
+ int local_cpu;
+ struct work_struct work;
+
+ local_cpu = get_cpu();
+ if (local_cpu == cpu) {
+ drain_page_cgroup_local(NULL);
+ put_cpu();
+ return;
+ }
+ put_cpu();
+
+ INIT_WORK(&work, drain_page_cgroup_local);
+ schedule_work_on(cpu, &work);
+ flush_work(&work);
+}
+
+static void drain_page_cgroup_all(void)
+{
+ mutex_lock(&memcg_force_drain_mutex);
+ schedule_on_each_cpu(drain_page_cgroup_local);
+ mutex_unlock(&memcg_force_drain_mutex);
+}
+
+
/*
* Charge the memory controller for page usage.
* Return
@@ -703,8 +814,6 @@ __mem_cgroup_uncharge_common(struct page
{
struct page_cgroup *pc;
struct mem_cgroup *mem;
- struct mem_cgroup_per_zone *mz;
- unsigned long flags;

if (mem_cgroup_subsys.disabled)
return;
@@ -722,16 +831,10 @@ __mem_cgroup_uncharge_common(struct page
}
ClearPageCgroupUsed(pc);
unlock_page_cgroup(pc);
+ preempt_enable();

mem = pc->mem_cgroup;
- mz = page_cgroup_zoneinfo(pc);
-
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_remove_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
- pc->mem_cgroup = NULL;
- css_put(&mem->css);
- preempt_enable();
+ release_page_cgroup(pc);
res_counter_uncharge(&mem->res, PAGE_SIZE);

return;
@@ -889,6 +992,7 @@ static void mem_cgroup_force_empty_list(
if (!PageLRU(page) || !get_page_unless_zero(page)) {
list_move(&pc->lru, list);
spin_unlock_irqrestore(&mz->lru_lock, flags);
+ drain_page_cgroup_all();
yield();
spin_lock_irqsave(&mz->lru_lock, flags);
continue;
@@ -907,6 +1011,7 @@ static void mem_cgroup_force_empty_list(
unlock_page(page);
put_page(page);
spin_unlock_irqrestore(&mz->lru_lock, flags);
+ drain_page_cgroup_all();
yield();
spin_lock_irqsave(&mz->lru_lock, flags);
} else {
@@ -935,6 +1040,7 @@ static int mem_cgroup_force_empty(struct
* So, we have to do loop here until all lists are empty.
*/
while (mem->res.usage > 0) {
+ drain_page_cgroup_all();
if (atomic_read(&mem->css.cgroup->count) > 0)
goto out;
for_each_node_state(node, N_POSSIBLE)
@@ -947,6 +1053,7 @@ static int mem_cgroup_force_empty(struct
}
}
ret = 0;
+ drain_page_cgroup_all();
out:
css_put(&mem->css);
return ret;
@@ -1151,6 +1258,38 @@ static void mem_cgroup_free(struct mem_c
vfree(mem);
}

+static void mem_cgroup_init_pcp(int cpu)
+{
+ page_cgroup_start_cache_cpu(cpu);
+}
+
+static int cpu_memcgroup_callback(struct notifier_block *nb,
+ unsigned long action, void *hcpu)
+{
+ int cpu = (long)hcpu;
+
+ switch(action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ mem_cgroup_init_pcp(cpu);
+ break;
+#ifdef CONFIG_HOTPLUG_CPU
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ page_cgroup_stop_cache_cpu(cpu);
+ drain_page_cgroup_cpu(cpu);
+ break;
+#endif
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __refdata memcgroup_nb =
+{
+ .notifier_call = cpu_memcgroup_callback,
+};

static struct cgroup_subsys_state *
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
@@ -1161,6 +1300,10 @@ mem_cgroup_create(struct cgroup_subsys *
if (unlikely((cont->parent) == NULL)) {
page_cgroup_init();
mem = &init_mem_cgroup;
+ cpu_memcgroup_callback(&memcgroup_nb,
+ (unsigned long)CPU_UP_PREPARE,
+ (void *)(long)smp_processor_id());
+ register_hotcpu_notifier(&memcgroup_nb);
} else {
mem = mem_cgroup_alloc();
if (!mem)