+ int ret;
+
+ if (mem_cgroup_disabled())
+ return 0;
+
+ if (!do_swap_account)
+ goto charge_cur_mm;
+ /*
+ * A racing thread's fault, or swapoff, may have already updated
+ * the pte, and even removed page from swap cache: return success
+ * to go on to do_swap_page()'s pte_same() test, which should fail.
+ */
+ if (!PageSwapCache(page))
+ return 0;
+ mem = try_get_mem_cgroup_from_swapcache(page);
+ if (!mem)
+ 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:
+ if (unlikely(!mm))
+ mm = &init_mm;
+ return __mem_cgroup_try_charge(mm, mask, ptr, true);
+}
+
+static void
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+ enum charge_type ctype)
+{
+ struct page_cgroup *pc;
+
+ if (mem_cgroup_disabled())
+ return;
+ if (!ptr)
+ return;
+ pc = lookup_page_cgroup(page);
+ mem_cgroup_lru_del_before_commit_swapcache(page);
+ __mem_cgroup_commit_charge(ptr, pc, ctype);
+ mem_cgroup_lru_add_after_commit_swapcache(page);
+ /*
+ * Now swap is on-memory. This means this page may be
+ * counted both as mem and swap....double count.
+ * Fix it by uncharging from memsw. Basically, this SwapCache is stable
+ * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
+ * may call delete_from_swap_cache() before reach here.
+ */
+ if (do_swap_account && PageSwapCache(page)) {
+ swp_entry_t ent = {.val = page_private(page)};
+ unsigned short id;
+ struct mem_cgroup *memcg;
+
+ id = swap_cgroup_record(ent, 0);
+ rcu_read_lock();
+ memcg = mem_cgroup_lookup(id);
+ if (memcg) {
+ /*
+ * This recorded memcg can be obsolete one. So, avoid
+ * calling css_tryget
+ */
+ res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ mem_cgroup_put(memcg);
+ }
+ rcu_read_unlock();
+ }
+ /* add this page(page_cgroup) to the LRU we want. */
+
+}
+
+void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+{
+ __mem_cgroup_commit_charge_swapin(page, ptr,
+ MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
+{
+ if (mem_cgroup_disabled())
+ return;
+ if (!mem)
+ return;
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ if (do_swap_account)
+ res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ css_put(&mem->css);
+}
+
+
+/*
+ * uncharge if !page_mapped(page)
+ */
+static struct mem_cgroup *
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
+{
+ struct page_cgroup *pc;
+ struct mem_cgroup *mem = NULL;