+ if (do_swap_account) {
+ if (res_counter_check_under_limit(&mem->res) &&
+ res_counter_check_under_limit(&mem->memsw))
+ return true;
+ } else
+ if (res_counter_check_under_limit(&mem->res))
+ return true;
+ return false;
+}
+
+static unsigned int get_swappiness(struct mem_cgroup *memcg)
+{
+ struct cgroup *cgrp = memcg->css.cgroup;
+ unsigned int swappiness;
+
+ /* root ? */
+ if (cgrp->parent == NULL)
+ return vm_swappiness;
+
+ spin_lock(&memcg->reclaim_param_lock);
+ swappiness = memcg->swappiness;
+ spin_unlock(&memcg->reclaim_param_lock);
+
+ return swappiness;
+}
+
+/*
+ * Dance down the hierarchy if needed to reclaim memory. We remember the
+ * last child we reclaimed from, so that we don't end up penalizing
+ * one child extensively based on its position in the children list.
+ *
+ * root_mem is the original ancestor that we've been reclaim from.
+ */
+static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
+ gfp_t gfp_mask, bool noswap)
+{
+ struct mem_cgroup *next_mem;
+ int ret = 0;
+
+ /*
+ * Reclaim unconditionally and don't check for return value.
+ * We need to reclaim in the current group and down the tree.
+ * One might think about checking for children before reclaiming,
+ * but there might be left over accounting, even after children
+ * have left.
+ */
+ ret += try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap,
+ get_swappiness(root_mem));
+ if (mem_cgroup_check_under_limit(root_mem))
+ return 1; /* indicate reclaim has succeeded */
+ if (!root_mem->use_hierarchy)
+ return ret;
+
+ next_mem = mem_cgroup_get_next_node(root_mem);
+
+ while (next_mem != root_mem) {
+ if (mem_cgroup_is_obsolete(next_mem)) {
+ next_mem = mem_cgroup_get_next_node(root_mem);
+ continue;
+ }
+ ret += try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap,
+ get_swappiness(next_mem));
+ if (mem_cgroup_check_under_limit(root_mem))
+ return 1; /* indicate reclaim has succeeded */
+ next_mem = mem_cgroup_get_next_node(root_mem);
+ }
+ return ret;
+}
+
+bool mem_cgroup_oom_called(struct task_struct *task)
+{
+ bool ret = false;
+ struct mem_cgroup *mem;
+ struct mm_struct *mm;
+
+ rcu_read_lock();
+ mm = task->mm;
+ if (!mm)
+ mm = &init_mm;
+ mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
+ ret = true;
+ rcu_read_unlock();
+ return ret;
+}
+/*
+ * 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)
+{
+ struct mem_cgroup *mem, *mem_over_limit;
+ int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ struct res_counter *fail_res;
+
+ if (unlikely(test_thread_flag(TIF_MEMDIE))) {
+ /* Don't account this! */
+ *memcg = NULL;
+ return 0;
+ }
+
+ /*
+ * 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).
+ */
+ 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(mem_cgroup_is_obsolete(mem));
+
+ while (1) {
+ int ret;
+ bool noswap = false;
+
+ ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
+ if (likely(!ret)) {
+ if (!do_swap_account)
+ break;
+ ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
+ &fail_res);
+ if (likely(!ret))
+ break;
+ /* mem+swap counter fails */
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ noswap = true;
+ 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);
+
+ if (!(gfp_mask & __GFP_WAIT))
+ goto nomem;
+
+ ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
+ noswap);
+ if (ret)
+ continue;
+
+ /*
+ * 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 (mem_cgroup_check_under_limit(mem_over_limit))
+ continue;
+
+ if (!nr_retries--) {
+ if (oom) {
+ mutex_lock(&memcg_tasklist);
+ mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
+ mutex_unlock(&memcg_tasklist);
+ mem_over_limit->last_oom_jiffies = jiffies;
+ }
+ goto nomem;
+ }
+ }
+ return 0;
+nomem:
+ css_put(&mem->css);
+ return -ENOMEM;
+}
+
+static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
+{
+ struct mem_cgroup *mem;
+ swp_entry_t ent;
+
+ if (!PageSwapCache(page))
+ return NULL;
+
+ ent.val = page_private(page);
+ mem = lookup_swap_cgroup(ent);
+ if (!mem)
+ return NULL;
+ if (!css_tryget(&mem->css))
+ return NULL;
+ return mem;
+}
+
+/*
+ * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
+ * USED state. If already USED, uncharge and return.
+ */
+
+static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
+ struct page_cgroup *pc,
+ enum charge_type ctype)
+{
+ /* try_charge() can return NULL to *memcg, taking care of it. */
+ if (!mem)
+ return;
+
+ lock_page_cgroup(pc);
+ if (unlikely(PageCgroupUsed(pc))) {
+ unlock_page_cgroup(pc);
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ if (do_swap_account)
+ res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ css_put(&mem->css);
+ return;
+ }
+ pc->mem_cgroup = mem;
+ smp_wmb();
+ pc->flags = pcg_default_flags[ctype];
+
+ mem_cgroup_charge_statistics(mem, pc, true);
+
+ unlock_page_cgroup(pc);
+}
+
+/**
+ * mem_cgroup_move_account - move account of the page
+ * @pc: page_cgroup of the page.
+ * @from: mem_cgroup which the page is moved from.
+ * @to: mem_cgroup which the page is moved to. @from != @to.
+ *
+ * The caller must confirm following.
+ * - page is not on LRU (isolate_page() is useful.)
+ *
+ * returns 0 at success,
+ * returns -EBUSY when lock is busy or "pc" is unstable.
+ *
+ * This function does "uncharge" from old cgroup but doesn't do "charge" to
+ * new cgroup. It should be done by a caller.
+ */
+
+static int mem_cgroup_move_account(struct page_cgroup *pc,
+ struct mem_cgroup *from, struct mem_cgroup *to)
+{
+ struct mem_cgroup_per_zone *from_mz, *to_mz;
+ int nid, zid;
+ int ret = -EBUSY;
+
+ VM_BUG_ON(from == to);
+ VM_BUG_ON(PageLRU(pc->page));
+
+ nid = page_cgroup_nid(pc);
+ zid = page_cgroup_zid(pc);
+ from_mz = mem_cgroup_zoneinfo(from, nid, zid);
+ to_mz = mem_cgroup_zoneinfo(to, nid, zid);
+
+ if (!trylock_page_cgroup(pc))
+ return ret;
+
+ if (!PageCgroupUsed(pc))
+ goto out;
+
+ if (pc->mem_cgroup != from)
+ goto out;
+
+ res_counter_uncharge(&from->res, PAGE_SIZE);
+ mem_cgroup_charge_statistics(from, pc, false);
+ if (do_swap_account)
+ res_counter_uncharge(&from->memsw, PAGE_SIZE);
+ css_put(&from->css);
+
+ css_get(&to->css);
+ pc->mem_cgroup = to;
+ mem_cgroup_charge_statistics(to, pc, true);
+ ret = 0;
+out:
+ unlock_page_cgroup(pc);
+ return ret;
+}
+
+/*
+ * move charges to its parent.
+ */
+
+static int mem_cgroup_move_parent(struct page_cgroup *pc,
+ struct mem_cgroup *child,
+ gfp_t gfp_mask)
+{
+ struct page *page = pc->page;
+ struct cgroup *cg = child->css.cgroup;
+ struct cgroup *pcg = cg->parent;
+ struct mem_cgroup *parent;
+ int ret;
+
+ /* Is ROOT ? */
+ if (!pcg)
+ return -EINVAL;
+
+
+ parent = mem_cgroup_from_cont(pcg);
+
+
+ ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
+ if (ret || !parent)
+ return ret;
+
+ if (!get_page_unless_zero(page)) {
+ ret = -EBUSY;
+ goto uncharge;
+ }
+
+ ret = isolate_lru_page(page);
+
+ if (ret)
+ goto cancel;
+
+ ret = mem_cgroup_move_account(pc, child, parent);
+
+ putback_lru_page(page);
+ if (!ret) {
+ put_page(page);
+ /* drop extra refcnt by try_charge() */
+ css_put(&parent->css);
+ return 0;
+ }
+
+cancel:
+ put_page(page);
+uncharge:
+ /* drop extra refcnt by try_charge() */
+ css_put(&parent->css);
+ /* uncharge if move fails */
+ res_counter_uncharge(&parent->res, PAGE_SIZE);
+ if (do_swap_account)
+ res_counter_uncharge(&parent->memsw, PAGE_SIZE);
+ return ret;
+}
+
+/*
+ * Charge the memory controller for page usage.
+ * Return
+ * 0 if the charge was successful
+ * < 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)
+{
+ struct mem_cgroup *mem;
+ struct page_cgroup *pc;
+ int ret;
+
+ pc = lookup_page_cgroup(page);
+ /* can happen at boot */
+ if (unlikely(!pc))
+ return 0;
+ prefetchw(pc);
+
+ mem = memcg;
+ ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
+ if (ret || !mem)
+ return ret;
+
+ __mem_cgroup_commit_charge(mem, pc, ctype);
+ return 0;
+}
+
+int mem_cgroup_newpage_charge(struct page *page,
+ struct mm_struct *mm, gfp_t gfp_mask)
+{
+ if (mem_cgroup_disabled())
+ return 0;
+ if (PageCompound(page))
+ return 0;
+ /*
+ * If already mapped, we don't have to account.
+ * If page cache, page->mapping has address_space.
+ * But page->mapping may have out-of-use anon_vma pointer,
+ * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
+ * is NULL.
+ */
+ if (page_mapped(page) || (page->mapping && !PageAnon(page)))
+ return 0;