#include <linux/memcontrol.h>
#include <linux/cgroup.h>
#include <linux/mm.h>
+#include <linux/smp.h>
#include <linux/page-flags.h>
#include <linux/backing-dev.h>
#include <linux/bit_spinlock.h>
#include <linux/swap.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
+#include <linux/seq_file.h>
#include <asm/uaccess.h>
struct cgroup_subsys mem_cgroup_subsys;
static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
+/*
+ * Statistics for memory cgroup.
+ */
+enum mem_cgroup_stat_index {
+ /*
+ * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
+ */
+ MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
+ MEM_CGROUP_STAT_RSS, /* # of pages charged as rss */
+
+ MEM_CGROUP_STAT_NSTATS,
+};
+
+struct mem_cgroup_stat_cpu {
+ s64 count[MEM_CGROUP_STAT_NSTATS];
+} ____cacheline_aligned_in_smp;
+
+struct mem_cgroup_stat {
+ struct mem_cgroup_stat_cpu cpustat[NR_CPUS];
+};
+
+/*
+ * For accounting under irq disable, no need for increment preempt count.
+ */
+static void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat *stat,
+ enum mem_cgroup_stat_index idx, int val)
+{
+ int cpu = smp_processor_id();
+ stat->cpustat[cpu].count[idx] += val;
+}
+
+static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
+ enum mem_cgroup_stat_index idx)
+{
+ int cpu;
+ s64 ret = 0;
+ for_each_possible_cpu(cpu)
+ ret += stat->cpustat[cpu].count[idx];
+ return ret;
+}
+
/*
* The memory controller data structure. The memory controller controls both
* page cache and RSS per cgroup. We would eventually like to provide
*/
spinlock_t lru_lock;
unsigned long control_type; /* control RSS or RSS+Pagecache */
+ /*
+ * statistics.
+ */
+ struct mem_cgroup_stat stat;
};
/*
struct mem_cgroup *mem_cgroup;
atomic_t ref_cnt; /* Helpful when pages move b/w */
/* mapped and cached states */
+ int flags;
};
+#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
+#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
enum {
MEM_CGROUP_TYPE_UNSPEC = 0,
MEM_CGROUP_TYPE_MAX,
};
+enum charge_type {
+ MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
+ MEM_CGROUP_CHARGE_TYPE_MAPPED,
+};
+
+/*
+ * Always modified under lru lock. Then, not necessary to preempt_disable()
+ */
+static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags,
+ bool charge)
+{
+ int val = (charge)? 1 : -1;
+ struct mem_cgroup_stat *stat = &mem->stat;
+ VM_BUG_ON(!irqs_disabled());
+
+ if (flags & PAGE_CGROUP_FLAG_CACHE)
+ __mem_cgroup_stat_add_safe(stat,
+ MEM_CGROUP_STAT_CACHE, val);
+ else
+ __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val);
+
+}
+
static struct mem_cgroup init_mem_cgroup;
static inline
struct mem_cgroup, css);
}
-inline struct mem_cgroup *mm_cgroup(struct mm_struct *mm)
-{
- return rcu_dereference(mm->mem_cgroup);
-}
-
void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)
{
struct mem_cgroup *mem;
bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
}
+/*
+ * Tie new page_cgroup to struct page under lock_page_cgroup()
+ * This can fail if the page has been tied to a page_cgroup.
+ * If success, returns 0.
+ */
+static int page_cgroup_assign_new_page_cgroup(struct page *page,
+ struct page_cgroup *pc)
+{
+ int ret = 0;
+
+ lock_page_cgroup(page);
+ if (!page_get_page_cgroup(page))
+ page_assign_page_cgroup(page, pc);
+ else /* A page is tied to other pc. */
+ ret = 1;
+ unlock_page_cgroup(page);
+ return ret;
+}
+
+/*
+ * Clear page->page_cgroup member under lock_page_cgroup().
+ * If given "pc" value is different from one page->page_cgroup,
+ * page->cgroup is not cleared.
+ * Returns a value of page->page_cgroup at lock taken.
+ * A can can detect failure of clearing by following
+ * clear_page_cgroup(page, pc) == pc
+ */
+
+static struct page_cgroup *clear_page_cgroup(struct page *page,
+ struct page_cgroup *pc)
+{
+ struct page_cgroup *ret;
+ /* lock and clear */
+ lock_page_cgroup(page);
+ ret = page_get_page_cgroup(page);
+ if (likely(ret == pc))
+ page_assign_page_cgroup(page, NULL);
+ unlock_page_cgroup(page);
+ return ret;
+}
+
static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
{
- if (active)
+ if (active) {
+ pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
list_move(&pc->lru, &pc->mem_cgroup->active_list);
- else
+ } else {
+ pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
list_move(&pc->lru, &pc->mem_cgroup->inactive_list);
+ }
+}
+
+int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
+{
+ int ret;
+
+ task_lock(task);
+ ret = task->mm && mm_cgroup(task->mm) == mem;
+ task_unlock(task);
+ return ret;
}
/*
unsigned long scan;
LIST_HEAD(pc_list);
struct list_head *src;
- struct page_cgroup *pc;
+ struct page_cgroup *pc, *tmp;
if (active)
src = &mem_cont->active_list;
src = &mem_cont->inactive_list;
spin_lock(&mem_cont->lru_lock);
- for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) {
- pc = list_entry(src->prev, struct page_cgroup, lru);
+ scan = 0;
+ list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
+ if (scan >= nr_to_scan)
+ break;
page = pc->page;
VM_BUG_ON(!pc);
+ if (unlikely(!PageLRU(page)))
+ continue;
+
if (PageActive(page) && !active) {
__mem_cgroup_move_lists(pc, true);
- scan--;
continue;
}
if (!PageActive(page) && active) {
__mem_cgroup_move_lists(pc, false);
- scan--;
continue;
}
if (page_zone(page) != z)
continue;
- /*
- * Check if the meta page went away from under us
- */
- if (!list_empty(&pc->lru))
- list_move(&pc->lru, &pc_list);
- else
- continue;
+ scan++;
+ list_move(&pc->lru, &pc_list);
if (__isolate_lru_page(page, mode) == 0) {
list_move(&page->lru, dst);
* 0 if the charge was successful
* < 0 if the cgroup is over its limit
*/
-int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
- gfp_t gfp_mask)
+static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
+ gfp_t gfp_mask, enum charge_type ctype)
{
struct mem_cgroup *mem;
- struct page_cgroup *pc, *race_pc;
+ struct page_cgroup *pc;
unsigned long flags;
unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
* with it
*/
retry:
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- /*
- * The page_cgroup exists and the page has already been accounted
- */
- if (pc) {
- if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) {
- /* this page is under being uncharged ? */
- unlock_page_cgroup(page);
- cpu_relax();
- goto retry;
- } else
- goto done;
+ if (page) {
+ lock_page_cgroup(page);
+ pc = page_get_page_cgroup(page);
+ /*
+ * The page_cgroup exists and
+ * the page has already been accounted.
+ */
+ if (pc) {
+ if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) {
+ /* this page is under being uncharged ? */
+ unlock_page_cgroup(page);
+ cpu_relax();
+ goto retry;
+ } else {
+ unlock_page_cgroup(page);
+ goto done;
+ }
+ }
+ unlock_page_cgroup(page);
}
- unlock_page_cgroup(page);
-
pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
if (pc == NULL)
goto err;
- rcu_read_lock();
/*
- * We always charge the cgroup the mm_struct belongs to
- * the mm_struct's mem_cgroup changes on task migration if the
+ * We always charge the cgroup the mm_struct belongs to.
+ * The mm_struct's mem_cgroup changes on task migration if the
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
if (!mm)
mm = &init_mm;
+ rcu_read_lock();
mem = rcu_dereference(mm->mem_cgroup);
/*
* For every charge from the cgroup, increment reference
* the cgroup limit.
*/
while (res_counter_charge(&mem->res, PAGE_SIZE)) {
- bool is_atomic = gfp_mask & GFP_ATOMIC;
- /*
- * We cannot reclaim under GFP_ATOMIC, fail the charge
- */
- if (is_atomic)
- goto noreclaim;
+ if (!(gfp_mask & __GFP_WAIT))
+ goto out;
if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
continue;
*/
if (res_counter_check_under_limit(&mem->res))
continue;
- /*
- * Since we control both RSS and cache, we end up with a
- * very interesting scenario where we end up reclaiming
- * memory (essentially RSS), since the memory is pushed
- * to swap cache, we eventually end up adding those
- * pages back to our list. Hence we give ourselves a
- * few chances before we fail
- */
- else if (nr_retries--) {
- congestion_wait(WRITE, HZ/10);
- continue;
- }
-noreclaim:
- css_put(&mem->css);
- if (!is_atomic)
- mem_cgroup_out_of_memory(mem, GFP_KERNEL);
- goto free_pc;
- }
- lock_page_cgroup(page);
- /*
- * Check if somebody else beat us to allocating the page_cgroup
- */
- race_pc = page_get_page_cgroup(page);
- if (race_pc) {
- kfree(pc);
- pc = race_pc;
- atomic_inc(&pc->ref_cnt);
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
- goto done;
+ if (!nr_retries--) {
+ mem_cgroup_out_of_memory(mem, gfp_mask);
+ goto out;
+ }
+ congestion_wait(WRITE, HZ/10);
}
atomic_set(&pc->ref_cnt, 1);
pc->mem_cgroup = mem;
pc->page = page;
- page_assign_page_cgroup(page, pc);
+ pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
+ if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
+ pc->flags |= PAGE_CGROUP_FLAG_CACHE;
+
+ if (!page || page_cgroup_assign_new_page_cgroup(page, pc)) {
+ /*
+ * Another charge has been added to this page already.
+ * We take lock_page_cgroup(page) again and read
+ * page->cgroup, increment refcnt.... just retry is OK.
+ */
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ css_put(&mem->css);
+ kfree(pc);
+ if (!page)
+ goto done;
+ goto retry;
+ }
spin_lock_irqsave(&mem->lru_lock, flags);
+ /* Update statistics vector */
+ mem_cgroup_charge_statistics(mem, pc->flags, true);
list_add(&pc->lru, &mem->active_list);
spin_unlock_irqrestore(&mem->lru_lock, flags);
done:
- unlock_page_cgroup(page);
return 0;
-free_pc:
+out:
+ css_put(&mem->css);
kfree(pc);
err:
return -ENOMEM;
}
+int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
+ gfp_t gfp_mask)
+{
+ return mem_cgroup_charge_common(page, mm, gfp_mask,
+ MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
/*
* See if the cached pages should be charged at all?
*/
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
+ int ret = 0;
struct mem_cgroup *mem;
if (!mm)
mm = &init_mm;
+ rcu_read_lock();
mem = rcu_dereference(mm->mem_cgroup);
+ css_get(&mem->css);
+ rcu_read_unlock();
if (mem->control_type == MEM_CGROUP_TYPE_ALL)
- return mem_cgroup_charge(page, mm, gfp_mask);
- else
- return 0;
+ ret = mem_cgroup_charge_common(page, mm, gfp_mask,
+ MEM_CGROUP_CHARGE_TYPE_CACHE);
+ css_put(&mem->css);
+ return ret;
}
/*
if (atomic_dec_and_test(&pc->ref_cnt)) {
page = pc->page;
- lock_page_cgroup(page);
- mem = pc->mem_cgroup;
- css_put(&mem->css);
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
- res_counter_uncharge(&mem->res, PAGE_SIZE);
+ /*
+ * get page->cgroup and clear it under lock.
+ * force_empty can drop page->cgroup without checking refcnt.
+ */
+ if (clear_page_cgroup(page, pc) == pc) {
+ mem = pc->mem_cgroup;
+ css_put(&mem->css);
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ spin_lock_irqsave(&mem->lru_lock, flags);
+ list_del_init(&pc->lru);
+ mem_cgroup_charge_statistics(mem, pc->flags, false);
+ spin_unlock_irqrestore(&mem->lru_lock, flags);
+ kfree(pc);
+ }
+ }
+}
+/*
+ * Returns non-zero if a page (under migration) has valid page_cgroup member.
+ * Refcnt of page_cgroup is incremented.
+ */
- spin_lock_irqsave(&mem->lru_lock, flags);
- list_del_init(&pc->lru);
- spin_unlock_irqrestore(&mem->lru_lock, flags);
- kfree(pc);
+int mem_cgroup_prepare_migration(struct page *page)
+{
+ struct page_cgroup *pc;
+ int ret = 0;
+ lock_page_cgroup(page);
+ pc = page_get_page_cgroup(page);
+ if (pc && atomic_inc_not_zero(&pc->ref_cnt))
+ ret = 1;
+ unlock_page_cgroup(page);
+ return ret;
+}
+
+void mem_cgroup_end_migration(struct page *page)
+{
+ struct page_cgroup *pc = page_get_page_cgroup(page);
+ mem_cgroup_uncharge(pc);
+}
+/*
+ * We know both *page* and *newpage* are now not-on-LRU and Pg_locked.
+ * And no race with uncharge() routines because page_cgroup for *page*
+ * has extra one reference by mem_cgroup_prepare_migration.
+ */
+
+void mem_cgroup_page_migration(struct page *page, struct page *newpage)
+{
+ struct page_cgroup *pc;
+retry:
+ pc = page_get_page_cgroup(page);
+ if (!pc)
+ return;
+ if (clear_page_cgroup(page, pc) != pc)
+ goto retry;
+ pc->page = newpage;
+ lock_page_cgroup(newpage);
+ page_assign_page_cgroup(newpage, pc);
+ unlock_page_cgroup(newpage);
+ return;
+}
+
+/*
+ * 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.
+ */
+#define FORCE_UNCHARGE_BATCH (128)
+static void
+mem_cgroup_force_empty_list(struct mem_cgroup *mem, struct list_head *list)
+{
+ struct page_cgroup *pc;
+ struct page *page;
+ int count;
+ unsigned long flags;
+
+retry:
+ count = FORCE_UNCHARGE_BATCH;
+ spin_lock_irqsave(&mem->lru_lock, flags);
+
+ while (--count && !list_empty(list)) {
+ pc = list_entry(list->prev, struct page_cgroup, lru);
+ page = pc->page;
+ /* Avoid race with charge */
+ atomic_set(&pc->ref_cnt, 0);
+ if (clear_page_cgroup(page, pc) == pc) {
+ css_put(&mem->css);
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ list_del_init(&pc->lru);
+ mem_cgroup_charge_statistics(mem, pc->flags, false);
+ kfree(pc);
+ } else /* being uncharged ? ...do relax */
+ break;
+ }
+ spin_unlock_irqrestore(&mem->lru_lock, flags);
+ if (!list_empty(list)) {
+ cond_resched();
+ goto retry;
}
+ return;
+}
+
+/*
+ * make mem_cgroup's charge to be 0 if there is no task.
+ * This enables deleting this mem_cgroup.
+ */
+
+int mem_cgroup_force_empty(struct mem_cgroup *mem)
+{
+ int ret = -EBUSY;
+ css_get(&mem->css);
+ /*
+ * page reclaim code (kswapd etc..) will move pages between
+` * active_list <-> inactive_list while we don't take a lock.
+ * So, we have to do loop here until all lists are empty.
+ */
+ while (!(list_empty(&mem->active_list) &&
+ list_empty(&mem->inactive_list))) {
+ if (atomic_read(&mem->css.cgroup->count) > 0)
+ goto out;
+ /* drop all page_cgroup in active_list */
+ mem_cgroup_force_empty_list(mem, &mem->active_list);
+ /* drop all page_cgroup in inactive_list */
+ mem_cgroup_force_empty_list(mem, &mem->inactive_list);
+ }
+ ret = 0;
+out:
+ css_put(&mem->css);
+ return ret;
}
+
+
int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
{
*tmp = memparse(buf, &buf);
ppos, buf, s - buf);
}
+
+static ssize_t mem_force_empty_write(struct cgroup *cont,
+ struct cftype *cft, struct file *file,
+ const char __user *userbuf,
+ size_t nbytes, loff_t *ppos)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+ int ret;
+ ret = mem_cgroup_force_empty(mem);
+ if (!ret)
+ ret = nbytes;
+ return ret;
+}
+
+/*
+ * Note: This should be removed if cgroup supports write-only file.
+ */
+
+static ssize_t mem_force_empty_read(struct cgroup *cont,
+ struct cftype *cft,
+ struct file *file, char __user *userbuf,
+ size_t nbytes, loff_t *ppos)
+{
+ return -EINVAL;
+}
+
+
+static const struct mem_cgroup_stat_desc {
+ const char *msg;
+ u64 unit;
+} mem_cgroup_stat_desc[] = {
+ [MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, },
+ [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
+};
+
+static int mem_control_stat_show(struct seq_file *m, void *arg)
+{
+ struct cgroup *cont = m->private;
+ struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
+ struct mem_cgroup_stat *stat = &mem_cont->stat;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) {
+ s64 val;
+
+ val = mem_cgroup_read_stat(stat, i);
+ val *= mem_cgroup_stat_desc[i].unit;
+ seq_printf(m, "%s %lld\n", mem_cgroup_stat_desc[i].msg,
+ (long long)val);
+ }
+ return 0;
+}
+
+static const struct file_operations mem_control_stat_file_operations = {
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int mem_control_stat_open(struct inode *unused, struct file *file)
+{
+ /* XXX __d_cont */
+ struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;
+
+ file->f_op = &mem_control_stat_file_operations;
+ return single_open(file, mem_control_stat_show, cont);
+}
+
+
+
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
.write = mem_control_type_write,
.read = mem_control_type_read,
},
+ {
+ .name = "force_empty",
+ .write = mem_force_empty_write,
+ .read = mem_force_empty_read,
+ },
+ {
+ .name = "stat",
+ .open = mem_control_stat_open,
+ },
};
static struct mem_cgroup init_mem_cgroup;
return &mem->css;
}
+static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
+ struct cgroup *cont)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+ mem_cgroup_force_empty(mem);
+}
+
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
.name = "memory",
.subsys_id = mem_cgroup_subsys_id,
.create = mem_cgroup_create,
+ .pre_destroy = mem_cgroup_pre_destroy,
.destroy = mem_cgroup_destroy,
.populate = mem_cgroup_populate,
.attach = mem_cgroup_move_task,
projects / linux-2.6 / blobdiff