#include <linux/mm_inline.h>
#include <linux/page_cgroup.h>
#include <linux/cpu.h>
+#include <linux/oom.h>
#include "internal.h"
#include <asm/uaccess.h>
/* "mc" and its members are protected by cgroup_mutex */
static struct move_charge_struct {
+ spinlock_t lock; /* for from, to, moving_task */
struct mem_cgroup *from;
struct mem_cgroup *to;
unsigned long precharge;
struct task_struct *moving_task; /* a task moving charges */
wait_queue_head_t waitq; /* a waitq for other context */
} mc = {
+ .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
};
{
int ret;
struct mem_cgroup *curr = NULL;
+ struct task_struct *p;
- task_lock(task);
- rcu_read_lock();
- curr = try_get_mem_cgroup_from_mm(task->mm);
- rcu_read_unlock();
- task_unlock(task);
+ p = find_lock_task_mm(task);
+ if (!p)
+ return 0;
+ curr = try_get_mem_cgroup_from_mm(p->mm);
+ task_unlock(p);
if (!curr)
return 0;
/*
struct zone *zone,
enum lru_list lru)
{
- int nid = zone->zone_pgdat->node_id;
+ int nid = zone_to_nid(zone);
int zid = zone_idx(zone);
struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
struct zone *zone)
{
- int nid = zone->zone_pgdat->node_id;
+ int nid = zone_to_nid(zone);
int zid = zone_idx(zone);
struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
LIST_HEAD(pc_list);
struct list_head *src;
struct page_cgroup *pc, *tmp;
- int nid = z->zone_pgdat->node_id;
+ int nid = zone_to_nid(z);
int zid = zone_idx(z);
struct mem_cgroup_per_zone *mz;
int lru = LRU_FILE * file + active;
return swappiness;
}
+/* A routine for testing mem is not under move_account */
+
+static bool mem_cgroup_under_move(struct mem_cgroup *mem)
+{
+ struct mem_cgroup *from;
+ struct mem_cgroup *to;
+ bool ret = false;
+ /*
+ * Unlike task_move routines, we access mc.to, mc.from not under
+ * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
+ */
+ spin_lock(&mc.lock);
+ from = mc.from;
+ to = mc.to;
+ if (!from)
+ goto unlock;
+ if (from == mem || to == mem
+ || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
+ || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
+ ret = true;
+unlock:
+ spin_unlock(&mc.lock);
+ return ret;
+}
+
+static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
+{
+ if (mc.moving_task && current != mc.moving_task) {
+ if (mem_cgroup_under_move(mem)) {
+ DEFINE_WAIT(wait);
+ prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
+ /* moving charge context might have finished. */
+ if (mc.moving_task)
+ schedule();
+ finish_wait(&mc.waitq, &wait);
+ return true;
+ }
+ }
+ return false;
+}
+
static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
{
int *val = data;
/* we use swappiness of local cgroup */
if (check_soft)
ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
- noswap, get_swappiness(victim), zone,
- zone->zone_pgdat->node_id);
+ noswap, get_swappiness(victim), zone);
else
ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
noswap, get_swappiness(victim));
static void memcg_oom_recover(struct mem_cgroup *mem)
{
- if (atomic_read(&mem->oom_lock))
+ if (mem && atomic_read(&mem->oom_lock))
memcg_wakeup_oom(mem);
}
return NOTIFY_OK;
}
+
+/* See __mem_cgroup_try_charge() for details */
+enum {
+ CHARGE_OK, /* success */
+ CHARGE_RETRY, /* need to retry but retry is not bad */
+ CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
+ CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
+ CHARGE_OOM_DIE, /* the current is killed because of OOM */
+};
+
+static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
+ int csize, bool oom_check)
+{
+ struct mem_cgroup *mem_over_limit;
+ struct res_counter *fail_res;
+ unsigned long flags = 0;
+ int ret;
+
+ ret = res_counter_charge(&mem->res, csize, &fail_res);
+
+ if (likely(!ret)) {
+ if (!do_swap_account)
+ return CHARGE_OK;
+ ret = res_counter_charge(&mem->memsw, csize, &fail_res);
+ if (likely(!ret))
+ return CHARGE_OK;
+
+ mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
+ flags |= MEM_CGROUP_RECLAIM_NOSWAP;
+ } else
+ mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
+
+ if (csize > PAGE_SIZE) /* change csize and retry */
+ return CHARGE_RETRY;
+
+ if (!(gfp_mask & __GFP_WAIT))
+ return CHARGE_WOULDBLOCK;
+
+ ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
+ gfp_mask, flags);
+ /*
+ * try_to_free_mem_cgroup_pages() might not give us a full
+ * picture of reclaim. Some pages are reclaimed and might be
+ * moved to swap cache or just unmapped from the cgroup.
+ * Check the limit again to see if the reclaim reduced the
+ * current usage of the cgroup before giving up
+ */
+ if (ret || mem_cgroup_check_under_limit(mem_over_limit))
+ return CHARGE_RETRY;
+
+ /*
+ * At task move, charge accounts can be doubly counted. So, it's
+ * better to wait until the end of task_move if something is going on.
+ */
+ if (mem_cgroup_wait_acct_move(mem_over_limit))
+ return CHARGE_RETRY;
+
+ /* If we don't need to call oom-killer at el, return immediately */
+ if (!oom_check)
+ return CHARGE_NOMEM;
+ /* check OOM */
+ if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
+ return CHARGE_OOM_DIE;
+
+ return CHARGE_RETRY;
+}
+
/*
* Unlike exported interface, "oom" parameter is added. if oom==true,
* oom-killer can be invoked.
*/
static int __mem_cgroup_try_charge(struct mm_struct *mm,
- gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom)
+ gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom)
{
- struct mem_cgroup *mem, *mem_over_limit;
- int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
- struct res_counter *fail_res;
+ int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ struct mem_cgroup *mem = NULL;
+ int ret;
int csize = CHARGE_SIZE;
/*
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
- mem = *memcg;
- if (likely(!mem)) {
- mem = try_get_mem_cgroup_from_mm(mm);
- *memcg = mem;
- } else {
- css_get(&mem->css);
- }
- if (unlikely(!mem))
- return 0;
-
- VM_BUG_ON(css_is_removed(&mem->css));
- if (mem_cgroup_is_root(mem))
- goto done;
-
- while (1) {
- int ret = 0;
- unsigned long flags = 0;
-
+ if (!*memcg && !mm)
+ goto bypass;
+again:
+ if (*memcg) { /* css should be a valid one */
+ mem = *memcg;
+ VM_BUG_ON(css_is_removed(&mem->css));
+ if (mem_cgroup_is_root(mem))
+ goto done;
if (consume_stock(mem))
goto done;
+ css_get(&mem->css);
+ } else {
+ struct task_struct *p;
- ret = res_counter_charge(&mem->res, csize, &fail_res);
- if (likely(!ret)) {
- if (!do_swap_account)
- break;
- ret = res_counter_charge(&mem->memsw, csize, &fail_res);
- if (likely(!ret))
- break;
- /* mem+swap counter fails */
- res_counter_uncharge(&mem->res, csize);
- flags |= MEM_CGROUP_RECLAIM_NOSWAP;
- mem_over_limit = mem_cgroup_from_res_counter(fail_res,
- memsw);
- } else
- /* mem counter fails */
- mem_over_limit = mem_cgroup_from_res_counter(fail_res,
- res);
-
- /* reduce request size and retry */
- if (csize > PAGE_SIZE) {
- csize = PAGE_SIZE;
- continue;
- }
- if (!(gfp_mask & __GFP_WAIT))
- goto nomem;
-
- ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
- gfp_mask, flags);
- if (ret)
- continue;
-
+ rcu_read_lock();
+ p = rcu_dereference(mm->owner);
+ VM_BUG_ON(!p);
/*
- * try_to_free_mem_cgroup_pages() might not give us a full
- * picture of reclaim. Some pages are reclaimed and might be
- * moved to swap cache or just unmapped from the cgroup.
- * Check the limit again to see if the reclaim reduced the
- * current usage of the cgroup before giving up
- *
+ * because we don't have task_lock(), "p" can exit while
+ * we're here. In that case, "mem" can point to root
+ * cgroup but never be NULL. (and task_struct itself is freed
+ * by RCU, cgroup itself is RCU safe.) Then, we have small
+ * risk here to get wrong cgroup. But such kind of mis-account
+ * by race always happens because we don't have cgroup_mutex().
+ * It's overkill and we allow that small race, here.
*/
- if (mem_cgroup_check_under_limit(mem_over_limit))
- continue;
-
- /* try to avoid oom while someone is moving charge */
- if (mc.moving_task && current != mc.moving_task) {
- struct mem_cgroup *from, *to;
- bool do_continue = false;
+ mem = mem_cgroup_from_task(p);
+ VM_BUG_ON(!mem);
+ if (mem_cgroup_is_root(mem)) {
+ rcu_read_unlock();
+ goto done;
+ }
+ if (consume_stock(mem)) {
/*
- * There is a small race that "from" or "to" can be
- * freed by rmdir, so we use css_tryget().
+ * It seems dagerous to access memcg without css_get().
+ * But considering how consume_stok works, it's not
+ * necessary. If consume_stock success, some charges
+ * from this memcg are cached on this cpu. So, we
+ * don't need to call css_get()/css_tryget() before
+ * calling consume_stock().
*/
- from = mc.from;
- to = mc.to;
- if (from && css_tryget(&from->css)) {
- if (mem_over_limit->use_hierarchy)
- do_continue = css_is_ancestor(
- &from->css,
- &mem_over_limit->css);
- else
- do_continue = (from == mem_over_limit);
- css_put(&from->css);
- }
- if (!do_continue && to && css_tryget(&to->css)) {
- if (mem_over_limit->use_hierarchy)
- do_continue = css_is_ancestor(
- &to->css,
- &mem_over_limit->css);
- else
- do_continue = (to == mem_over_limit);
- css_put(&to->css);
- }
- if (do_continue) {
- DEFINE_WAIT(wait);
- prepare_to_wait(&mc.waitq, &wait,
- TASK_INTERRUPTIBLE);
- /* moving charge context might have finished. */
- if (mc.moving_task)
- schedule();
- finish_wait(&mc.waitq, &wait);
- continue;
- }
+ rcu_read_unlock();
+ goto done;
+ }
+ /* after here, we may be blocked. we need to get refcnt */
+ if (!css_tryget(&mem->css)) {
+ rcu_read_unlock();
+ goto again;
}
+ rcu_read_unlock();
+ }
- if (!nr_retries--) {
- if (!oom)
+ do {
+ bool oom_check;
+
+ /* If killed, bypass charge */
+ if (fatal_signal_pending(current)) {
+ css_put(&mem->css);
+ goto bypass;
+ }
+
+ oom_check = false;
+ if (oom && !nr_oom_retries) {
+ oom_check = true;
+ nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ }
+
+ ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
+
+ switch (ret) {
+ case CHARGE_OK:
+ break;
+ case CHARGE_RETRY: /* not in OOM situation but retry */
+ csize = PAGE_SIZE;
+ css_put(&mem->css);
+ mem = NULL;
+ goto again;
+ case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
+ css_put(&mem->css);
+ goto nomem;
+ case CHARGE_NOMEM: /* OOM routine works */
+ if (!oom) {
+ css_put(&mem->css);
goto nomem;
- if (mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) {
- nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
- continue;
}
- /* When we reach here, current task is dying .*/
+ /* If oom, we never return -ENOMEM */
+ nr_oom_retries--;
+ break;
+ case CHARGE_OOM_DIE: /* Killed by OOM Killer */
css_put(&mem->css);
goto bypass;
}
- }
+ } while (ret != CHARGE_OK);
+
if (csize > PAGE_SIZE)
refill_stock(mem, csize - PAGE_SIZE);
+ css_put(&mem->css);
done:
+ *memcg = mem;
return 0;
nomem:
- css_put(&mem->css);
+ *memcg = NULL;
return -ENOMEM;
bypass:
*memcg = NULL;
res_counter_uncharge(&mem->res, PAGE_SIZE * count);
if (do_swap_account)
res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
- VM_BUG_ON(test_bit(CSS_ROOT, &mem->css.flags));
- WARN_ON_ONCE(count > INT_MAX);
- __css_put(&mem->css, (int)count);
}
- /* we don't need css_put for root */
}
static void mem_cgroup_cancel_charge(struct mem_cgroup *mem)
* < 0 if the cgroup is over its limit
*/
static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
- gfp_t gfp_mask, enum charge_type ctype,
- struct mem_cgroup *memcg)
+ gfp_t gfp_mask, enum charge_type ctype)
{
- struct mem_cgroup *mem;
+ struct mem_cgroup *mem = NULL;
struct page_cgroup *pc;
int ret;
return 0;
prefetchw(pc);
- mem = memcg;
ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
if (ret || !mem)
return ret;
if (unlikely(!mm))
mm = &init_mm;
return mem_cgroup_charge_common(page, mm, gfp_mask,
- MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
+ MEM_CGROUP_CHARGE_TYPE_MAPPED);
}
static void
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
- struct mem_cgroup *mem = NULL;
int ret;
if (mem_cgroup_disabled())
if (!(gfp_mask & __GFP_WAIT)) {
struct page_cgroup *pc;
-
pc = lookup_page_cgroup(page);
if (!pc)
return 0;
unlock_page_cgroup(pc);
}
- if (unlikely(!mm && !mem))
+ if (unlikely(!mm))
mm = &init_mm;
if (page_is_file_cache(page))
return mem_cgroup_charge_common(page, mm, gfp_mask,
- MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
+ MEM_CGROUP_CHARGE_TYPE_CACHE);
/* shmem */
if (PageSwapCache(page)) {
+ struct mem_cgroup *mem = NULL;
+
ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
if (!ret)
__mem_cgroup_commit_charge_swapin(page, mem,
MEM_CGROUP_CHARGE_TYPE_SHMEM);
} else
ret = mem_cgroup_charge_common(page, mm, gfp_mask,
- MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
+ MEM_CGROUP_CHARGE_TYPE_SHMEM);
return ret;
}
goto charge_cur_mm;
*ptr = mem;
ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
- /* drop extra refcnt from tryget */
css_put(&mem->css);
return ret;
charge_cur_mm:
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
- struct mem_cgroup_per_zone *mz;
if (mem_cgroup_disabled())
return NULL;
break;
}
- if (!mem_cgroup_is_root(mem))
- __do_uncharge(mem, ctype);
- if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
- mem_cgroup_swap_statistics(mem, true);
mem_cgroup_charge_statistics(mem, pc, false);
ClearPageCgroupUsed(pc);
* special functions.
*/
- mz = page_cgroup_zoneinfo(pc);
unlock_page_cgroup(pc);
-
+ /*
+ * even after unlock, we have mem->res.usage here and this memcg
+ * will never be freed.
+ */
memcg_check_events(mem, page);
- /* at swapout, this memcg will be accessed to record to swap */
- if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
- css_put(&mem->css);
+ if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
+ mem_cgroup_swap_statistics(mem, true);
+ mem_cgroup_get(mem);
+ }
+ if (!mem_cgroup_is_root(mem))
+ __do_uncharge(mem, ctype);
return mem;
memcg = __mem_cgroup_uncharge_common(page, ctype);
- /* record memcg information */
- if (do_swap_account && swapout && memcg) {
+ /*
+ * record memcg information, if swapout && memcg != NULL,
+ * mem_cgroup_get() was called in uncharge().
+ */
+ if (do_swap_account && swapout && memcg)
swap_cgroup_record(ent, css_id(&memcg->css));
- mem_cgroup_get(memcg);
- }
- if (swapout && memcg)
- css_put(&memcg->css);
}
#endif
*/
if (!mem_cgroup_is_root(to))
res_counter_uncharge(&to->res, PAGE_SIZE);
- css_put(&to->css);
}
return 0;
}
ClearPageCgroupMigration(pc);
unlock_page_cgroup(pc);
- if (unused != oldpage)
- pc = lookup_page_cgroup(unused);
__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
- pc = lookup_page_cgroup(used);
/*
* If a page is a file cache, radix-tree replacement is very atomic
* and we can skip this check. When it was an Anon page, its mapcount
}
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
- gfp_t gfp_mask, int nid,
- int zid)
+ gfp_t gfp_mask)
{
unsigned long nr_reclaimed = 0;
struct mem_cgroup_per_zone *mz, *next_mz = NULL;
if (order > 0)
return 0;
- mctz = soft_limit_tree_node_zone(nid, zid);
+ mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
/*
* This loop can run a while, specially if mem_cgroup's continuously
* keep exceeding their soft limit and putting the system under
static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
- __mem_cgroup_threshold(memcg, false);
- if (do_swap_account)
- __mem_cgroup_threshold(memcg, true);
+ while (memcg) {
+ __mem_cgroup_threshold(memcg, false);
+ if (do_swap_account)
+ __mem_cgroup_threshold(memcg, true);
+
+ memcg = parent_mem_cgroup(memcg);
+ }
}
static int compare_thresholds(const void *a, const void *b)
return 0;
}
-/*
- */
static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
struct cftype *cft, u64 val)
{
goto one_by_one;
}
mc.precharge += count;
- VM_BUG_ON(test_bit(CSS_ROOT, &mem->css.flags));
- WARN_ON_ONCE(count > INT_MAX);
- __css_get(&mem->css, (int)count);
return ret;
}
one_by_one:
static void mem_cgroup_clear_mc(void)
{
+ struct mem_cgroup *from = mc.from;
+ struct mem_cgroup *to = mc.to;
+
/* we must uncharge all the leftover precharges from mc.to */
if (mc.precharge) {
__mem_cgroup_cancel_charge(mc.to, mc.precharge);
mc.precharge = 0;
- memcg_oom_recover(mc.to);
}
/*
* we didn't uncharge from mc.from at mem_cgroup_move_account(), so
if (mc.moved_charge) {
__mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
mc.moved_charge = 0;
- memcg_oom_recover(mc.from);
}
/* we must fixup refcnts and charges */
if (mc.moved_swap) {
- WARN_ON_ONCE(mc.moved_swap > INT_MAX);
/* uncharge swap account from the old cgroup */
if (!mem_cgroup_is_root(mc.from))
res_counter_uncharge(&mc.from->memsw,
*/
res_counter_uncharge(&mc.to->res,
PAGE_SIZE * mc.moved_swap);
- VM_BUG_ON(test_bit(CSS_ROOT, &mc.to->css.flags));
- __css_put(&mc.to->css, mc.moved_swap);
}
/* we've already done mem_cgroup_get(mc.to) */
mc.moved_swap = 0;
}
+ spin_lock(&mc.lock);
mc.from = NULL;
mc.to = NULL;
mc.moving_task = NULL;
+ spin_unlock(&mc.lock);
+ memcg_oom_recover(from);
+ memcg_oom_recover(to);
wake_up_all(&mc.waitq);
}
VM_BUG_ON(mc.moved_charge);
VM_BUG_ON(mc.moved_swap);
VM_BUG_ON(mc.moving_task);
+ spin_lock(&mc.lock);
mc.from = from;
mc.to = mem;
mc.precharge = 0;
mc.moved_charge = 0;
mc.moved_swap = 0;
mc.moving_task = current;
+ spin_unlock(&mc.lock);
ret = mem_cgroup_precharge_mc(mm);
if (ret)
git://bbs.cooldavid.org / net-next-2.6.git / blobdiff