Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e79cb59..46ad252 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* memcontrol.c - Memory Controller
  *
  * Copyright IBM Corporation, 2007
@@ -19,26 +20,17 @@
  * Lockless page tracking & accounting
  * Unified hierarchy configuration model
  * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/page_counter.h>
 #include <linux/memcontrol.h>
 #include <linux/cgroup.h>
-#include <linux/mm.h>
+#include <linux/pagewalk.h>
 #include <linux/sched/mm.h>
 #include <linux/shmem_fs.h>
 #include <linux/hugetlb.h>
 #include <linux/pagemap.h>
+#include <linux/vm_event_item.h>
 #include <linux/smp.h>
 #include <linux/page-flags.h>
 #include <linux/backing-dev.h>
@@ -65,6 +57,8 @@
 #include <linux/lockdep.h>
 #include <linux/file.h>
 #include <linux/tracehook.h>
+#include <linux/psi.h>
+#include <linux/seq_buf.h>
 #include "internal.h"
 #include <net/sock.h>
 #include <net/ip.h>
@@ -94,6 +88,10 @@
 #define do_swap_account		0
 #endif
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
+#endif
+
 /* Whether legacy memory+swap accounting is active */
 static bool do_memsw_account(void)
 {
@@ -248,6 +246,12 @@
 	     iter != NULL;				\
 	     iter = mem_cgroup_iter(NULL, iter, NULL))
 
+static inline bool should_force_charge(void)
+{
+	return tsk_is_oom_victim(current) || fatal_signal_pending(current) ||
+		(current->flags & PF_EXITING);
+}
+
 /* Some nice accessors for the vmpressure. */
 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
 {
@@ -314,6 +318,7 @@
 EXPORT_SYMBOL(memcg_kmem_enabled_key);
 
 struct workqueue_struct *memcg_kmem_cache_wq;
+#endif
 
 static int memcg_shrinker_map_size;
 static DEFINE_MUTEX(memcg_shrinker_map_mutex);
@@ -437,14 +442,6 @@
 	}
 }
 
-#else /* CONFIG_MEMCG_KMEM */
-static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
-{
-	return 0;
-}
-static void memcg_free_shrinker_maps(struct mem_cgroup *memcg) { }
-#endif /* CONFIG_MEMCG_KMEM */
-
 /**
  * mem_cgroup_css_from_page - css of the memcg associated with a page
  * @page: page of interest
@@ -487,7 +484,10 @@
 	unsigned long ino = 0;
 
 	rcu_read_lock();
-	memcg = READ_ONCE(page->mem_cgroup);
+	if (PageSlab(page) && !PageTail(page))
+		memcg = memcg_from_slab_page(page);
+	else
+		memcg = READ_ONCE(page->mem_cgroup);
 	while (memcg && !(memcg->css.flags & CSS_ONLINE))
 		memcg = parent_mem_cgroup(memcg);
 	if (memcg)
@@ -680,10 +680,153 @@
 	return mz;
 }
 
-static unsigned long memcg_sum_events(struct mem_cgroup *memcg,
-				      int event)
+/**
+ * __mod_memcg_state - update cgroup memory statistics
+ * @memcg: the memory cgroup
+ * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
+ * @val: delta to add to the counter, can be negative
+ */
+void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
 {
-	return atomic_long_read(&memcg->events[event]);
+	long x;
+
+	if (mem_cgroup_disabled())
+		return;
+
+	x = val + __this_cpu_read(memcg->vmstats_percpu->stat[idx]);
+	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
+		struct mem_cgroup *mi;
+
+		/*
+		 * Batch local counters to keep them in sync with
+		 * the hierarchical ones.
+		 */
+		__this_cpu_add(memcg->vmstats_local->stat[idx], x);
+		for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+			atomic_long_add(x, &mi->vmstats[idx]);
+		x = 0;
+	}
+	__this_cpu_write(memcg->vmstats_percpu->stat[idx], x);
+}
+
+static struct mem_cgroup_per_node *
+parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
+{
+	struct mem_cgroup *parent;
+
+	parent = parent_mem_cgroup(pn->memcg);
+	if (!parent)
+		return NULL;
+	return mem_cgroup_nodeinfo(parent, nid);
+}
+
+/**
+ * __mod_lruvec_state - update lruvec memory statistics
+ * @lruvec: the lruvec
+ * @idx: the stat item
+ * @val: delta to add to the counter, can be negative
+ *
+ * The lruvec is the intersection of the NUMA node and a cgroup. This
+ * function updates the all three counters that are affected by a
+ * change of state at this level: per-node, per-cgroup, per-lruvec.
+ */
+void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+			int val)
+{
+	pg_data_t *pgdat = lruvec_pgdat(lruvec);
+	struct mem_cgroup_per_node *pn;
+	struct mem_cgroup *memcg;
+	long x;
+
+	/* Update node */
+	__mod_node_page_state(pgdat, idx, val);
+
+	if (mem_cgroup_disabled())
+		return;
+
+	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+	memcg = pn->memcg;
+
+	/* Update memcg */
+	__mod_memcg_state(memcg, idx, val);
+
+	/* Update lruvec */
+	__this_cpu_add(pn->lruvec_stat_local->count[idx], val);
+
+	x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]);
+	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
+		struct mem_cgroup_per_node *pi;
+
+		for (pi = pn; pi; pi = parent_nodeinfo(pi, pgdat->node_id))
+			atomic_long_add(x, &pi->lruvec_stat[idx]);
+		x = 0;
+	}
+	__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
+}
+
+void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val)
+{
+	struct page *page = virt_to_head_page(p);
+	pg_data_t *pgdat = page_pgdat(page);
+	struct mem_cgroup *memcg;
+	struct lruvec *lruvec;
+
+	rcu_read_lock();
+	memcg = memcg_from_slab_page(page);
+
+	/* Untracked pages have no memcg, no lruvec. Update only the node */
+	if (!memcg || memcg == root_mem_cgroup) {
+		__mod_node_page_state(pgdat, idx, val);
+	} else {
+		lruvec = mem_cgroup_lruvec(pgdat, memcg);
+		__mod_lruvec_state(lruvec, idx, val);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * __count_memcg_events - account VM events in a cgroup
+ * @memcg: the memory cgroup
+ * @idx: the event item
+ * @count: the number of events that occured
+ */
+void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
+			  unsigned long count)
+{
+	unsigned long x;
+
+	if (mem_cgroup_disabled())
+		return;
+
+	x = count + __this_cpu_read(memcg->vmstats_percpu->events[idx]);
+	if (unlikely(x > MEMCG_CHARGE_BATCH)) {
+		struct mem_cgroup *mi;
+
+		/*
+		 * Batch local counters to keep them in sync with
+		 * the hierarchical ones.
+		 */
+		__this_cpu_add(memcg->vmstats_local->events[idx], x);
+		for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+			atomic_long_add(x, &mi->vmevents[idx]);
+		x = 0;
+	}
+	__this_cpu_write(memcg->vmstats_percpu->events[idx], x);
+}
+
+static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
+{
+	return atomic_long_read(&memcg->vmevents[event]);
+}
+
+static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
+{
+	long x = 0;
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		x += per_cpu(memcg->vmstats_local->events[event], cpu);
+	return x;
 }
 
 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
@@ -715,35 +858,7 @@
 		nr_pages = -nr_pages; /* for event */
 	}
 
-	__this_cpu_add(memcg->stat_cpu->nr_page_events, nr_pages);
-}
-
-unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
-					   int nid, unsigned int lru_mask)
-{
-	struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
-	unsigned long nr = 0;
-	enum lru_list lru;
-
-	VM_BUG_ON((unsigned)nid >= nr_node_ids);
-
-	for_each_lru(lru) {
-		if (!(BIT(lru) & lru_mask))
-			continue;
-		nr += mem_cgroup_get_lru_size(lruvec, lru);
-	}
-	return nr;
-}
-
-static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
-			unsigned int lru_mask)
-{
-	unsigned long nr = 0;
-	int nid;
-
-	for_each_node_state(nid, N_MEMORY)
-		nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
-	return nr;
+	__this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
 }
 
 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
@@ -751,8 +866,8 @@
 {
 	unsigned long val, next;
 
-	val = __this_cpu_read(memcg->stat_cpu->nr_page_events);
-	next = __this_cpu_read(memcg->stat_cpu->targets[target]);
+	val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
+	next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
 	/* from time_after() in jiffies.h */
 	if ((long)(next - val) < 0) {
 		switch (target) {
@@ -768,7 +883,7 @@
 		default:
 			break;
 		}
-		__this_cpu_write(memcg->stat_cpu->targets[target], next);
+		__this_cpu_write(memcg->vmstats_percpu->targets[target], next);
 		return true;
 	}
 	return false;
@@ -845,7 +960,7 @@
 			if (unlikely(!memcg))
 				memcg = root_mem_cgroup;
 		}
-	} while (!css_tryget_online(&memcg->css));
+	} while (!css_tryget(&memcg->css));
 	rcu_read_unlock();
 	return memcg;
 }
@@ -1031,26 +1146,45 @@
 		css_put(&prev->css);
 }
 
-static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
+					struct mem_cgroup *dead_memcg)
 {
-	struct mem_cgroup *memcg = dead_memcg;
 	struct mem_cgroup_reclaim_iter *iter;
 	struct mem_cgroup_per_node *mz;
 	int nid;
 	int i;
 
-	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
-		for_each_node(nid) {
-			mz = mem_cgroup_nodeinfo(memcg, nid);
-			for (i = 0; i <= DEF_PRIORITY; i++) {
-				iter = &mz->iter[i];
-				cmpxchg(&iter->position,
-					dead_memcg, NULL);
-			}
+	for_each_node(nid) {
+		mz = mem_cgroup_nodeinfo(from, nid);
+		for (i = 0; i <= DEF_PRIORITY; i++) {
+			iter = &mz->iter[i];
+			cmpxchg(&iter->position,
+				dead_memcg, NULL);
 		}
 	}
 }
 
+static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+{
+	struct mem_cgroup *memcg = dead_memcg;
+	struct mem_cgroup *last;
+
+	do {
+		__invalidate_reclaim_iterators(memcg, dead_memcg);
+		last = memcg;
+	} while ((memcg = parent_mem_cgroup(memcg)));
+
+	/*
+	 * When cgruop1 non-hierarchy mode is used,
+	 * parent_mem_cgroup() does not walk all the way up to the
+	 * cgroup root (root_mem_cgroup). So we have to handle
+	 * dead_memcg from cgroup root separately.
+	 */
+	if (last != root_mem_cgroup)
+		__invalidate_reclaim_iterators(root_mem_cgroup,
+						dead_memcg);
+}
+
 /**
  * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
  * @memcg: hierarchy root
@@ -1076,7 +1210,7 @@
 		struct css_task_iter it;
 		struct task_struct *task;
 
-		css_task_iter_start(&iter->css, 0, &it);
+		css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
 		while (!ret && (task = css_task_iter_next(&it)))
 			ret = fn(task, arg);
 		css_task_iter_end(&it);
@@ -1168,32 +1302,6 @@
 		*lru_size += nr_pages;
 }
 
-bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
-{
-	struct mem_cgroup *task_memcg;
-	struct task_struct *p;
-	bool ret;
-
-	p = find_lock_task_mm(task);
-	if (p) {
-		task_memcg = get_mem_cgroup_from_mm(p->mm);
-		task_unlock(p);
-	} else {
-		/*
-		 * All threads may have already detached their mm's, but the oom
-		 * killer still needs to detect if they have already been oom
-		 * killed to prevent needlessly killing additional tasks.
-		 */
-		rcu_read_lock();
-		task_memcg = mem_cgroup_from_task(task);
-		css_get(&task_memcg->css);
-		rcu_read_unlock();
-	}
-	ret = mem_cgroup_is_descendant(task_memcg, memcg);
-	css_put(&task_memcg->css);
-	return ret;
-}
-
 /**
  * mem_cgroup_margin - calculate chargeable space of a memory cgroup
  * @memcg: the memory cgroup
@@ -1269,85 +1377,174 @@
 	return false;
 }
 
-static const unsigned int memcg1_stats[] = {
-	MEMCG_CACHE,
-	MEMCG_RSS,
-	MEMCG_RSS_HUGE,
-	NR_SHMEM,
-	NR_FILE_MAPPED,
-	NR_FILE_DIRTY,
-	NR_WRITEBACK,
-	MEMCG_SWAP,
-};
+static char *memory_stat_format(struct mem_cgroup *memcg)
+{
+	struct seq_buf s;
+	int i;
 
-static const char *const memcg1_stat_names[] = {
-	"cache",
-	"rss",
-	"rss_huge",
-	"shmem",
-	"mapped_file",
-	"dirty",
-	"writeback",
-	"swap",
-};
+	seq_buf_init(&s, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE);
+	if (!s.buffer)
+		return NULL;
+
+	/*
+	 * Provide statistics on the state of the memory subsystem as
+	 * well as cumulative event counters that show past behavior.
+	 *
+	 * This list is ordered following a combination of these gradients:
+	 * 1) generic big picture -> specifics and details
+	 * 2) reflecting userspace activity -> reflecting kernel heuristics
+	 *
+	 * Current memory state:
+	 */
+
+	seq_buf_printf(&s, "anon %llu\n",
+		       (u64)memcg_page_state(memcg, MEMCG_RSS) *
+		       PAGE_SIZE);
+	seq_buf_printf(&s, "file %llu\n",
+		       (u64)memcg_page_state(memcg, MEMCG_CACHE) *
+		       PAGE_SIZE);
+	seq_buf_printf(&s, "kernel_stack %llu\n",
+		       (u64)memcg_page_state(memcg, MEMCG_KERNEL_STACK_KB) *
+		       1024);
+	seq_buf_printf(&s, "slab %llu\n",
+		       (u64)(memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) +
+			     memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE)) *
+		       PAGE_SIZE);
+	seq_buf_printf(&s, "sock %llu\n",
+		       (u64)memcg_page_state(memcg, MEMCG_SOCK) *
+		       PAGE_SIZE);
+
+	seq_buf_printf(&s, "shmem %llu\n",
+		       (u64)memcg_page_state(memcg, NR_SHMEM) *
+		       PAGE_SIZE);
+	seq_buf_printf(&s, "file_mapped %llu\n",
+		       (u64)memcg_page_state(memcg, NR_FILE_MAPPED) *
+		       PAGE_SIZE);
+	seq_buf_printf(&s, "file_dirty %llu\n",
+		       (u64)memcg_page_state(memcg, NR_FILE_DIRTY) *
+		       PAGE_SIZE);
+	seq_buf_printf(&s, "file_writeback %llu\n",
+		       (u64)memcg_page_state(memcg, NR_WRITEBACK) *
+		       PAGE_SIZE);
+
+	/*
+	 * TODO: We should eventually replace our own MEMCG_RSS_HUGE counter
+	 * with the NR_ANON_THP vm counter, but right now it's a pain in the
+	 * arse because it requires migrating the work out of rmap to a place
+	 * where the page->mem_cgroup is set up and stable.
+	 */
+	seq_buf_printf(&s, "anon_thp %llu\n",
+		       (u64)memcg_page_state(memcg, MEMCG_RSS_HUGE) *
+		       PAGE_SIZE);
+
+	for (i = 0; i < NR_LRU_LISTS; i++)
+		seq_buf_printf(&s, "%s %llu\n", mem_cgroup_lru_names[i],
+			       (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
+			       PAGE_SIZE);
+
+	seq_buf_printf(&s, "slab_reclaimable %llu\n",
+		       (u64)memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) *
+		       PAGE_SIZE);
+	seq_buf_printf(&s, "slab_unreclaimable %llu\n",
+		       (u64)memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE) *
+		       PAGE_SIZE);
+
+	/* Accumulated memory events */
+
+	seq_buf_printf(&s, "pgfault %lu\n", memcg_events(memcg, PGFAULT));
+	seq_buf_printf(&s, "pgmajfault %lu\n", memcg_events(memcg, PGMAJFAULT));
+
+	seq_buf_printf(&s, "workingset_refault %lu\n",
+		       memcg_page_state(memcg, WORKINGSET_REFAULT));
+	seq_buf_printf(&s, "workingset_activate %lu\n",
+		       memcg_page_state(memcg, WORKINGSET_ACTIVATE));
+	seq_buf_printf(&s, "workingset_nodereclaim %lu\n",
+		       memcg_page_state(memcg, WORKINGSET_NODERECLAIM));
+
+	seq_buf_printf(&s, "pgrefill %lu\n", memcg_events(memcg, PGREFILL));
+	seq_buf_printf(&s, "pgscan %lu\n",
+		       memcg_events(memcg, PGSCAN_KSWAPD) +
+		       memcg_events(memcg, PGSCAN_DIRECT));
+	seq_buf_printf(&s, "pgsteal %lu\n",
+		       memcg_events(memcg, PGSTEAL_KSWAPD) +
+		       memcg_events(memcg, PGSTEAL_DIRECT));
+	seq_buf_printf(&s, "pgactivate %lu\n", memcg_events(memcg, PGACTIVATE));
+	seq_buf_printf(&s, "pgdeactivate %lu\n", memcg_events(memcg, PGDEACTIVATE));
+	seq_buf_printf(&s, "pglazyfree %lu\n", memcg_events(memcg, PGLAZYFREE));
+	seq_buf_printf(&s, "pglazyfreed %lu\n", memcg_events(memcg, PGLAZYFREED));
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	seq_buf_printf(&s, "thp_fault_alloc %lu\n",
+		       memcg_events(memcg, THP_FAULT_ALLOC));
+	seq_buf_printf(&s, "thp_collapse_alloc %lu\n",
+		       memcg_events(memcg, THP_COLLAPSE_ALLOC));
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+	/* The above should easily fit into one page */
+	WARN_ON_ONCE(seq_buf_has_overflowed(&s));
+
+	return s.buffer;
+}
 
 #define K(x) ((x) << (PAGE_SHIFT-10))
 /**
- * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
+ * mem_cgroup_print_oom_context: Print OOM information relevant to
+ * memory controller.
  * @memcg: The memory cgroup that went over limit
  * @p: Task that is going to be killed
  *
  * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
  * enabled
  */
-void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
+void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
 {
-	struct mem_cgroup *iter;
-	unsigned int i;
-
 	rcu_read_lock();
 
+	if (memcg) {
+		pr_cont(",oom_memcg=");
+		pr_cont_cgroup_path(memcg->css.cgroup);
+	} else
+		pr_cont(",global_oom");
 	if (p) {
-		pr_info("Task in ");
+		pr_cont(",task_memcg=");
 		pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
-		pr_cont(" killed as a result of limit of ");
-	} else {
-		pr_info("Memory limit reached of cgroup ");
 	}
-
-	pr_cont_cgroup_path(memcg->css.cgroup);
-	pr_cont("\n");
-
 	rcu_read_unlock();
+}
+
+/**
+ * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
+ * memory controller.
+ * @memcg: The memory cgroup that went over limit
+ */
+void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
+{
+	char *buf;
 
 	pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
 		K((u64)page_counter_read(&memcg->memory)),
 		K((u64)memcg->memory.max), memcg->memory.failcnt);
-	pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
-		K((u64)page_counter_read(&memcg->memsw)),
-		K((u64)memcg->memsw.max), memcg->memsw.failcnt);
-	pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
-		K((u64)page_counter_read(&memcg->kmem)),
-		K((u64)memcg->kmem.max), memcg->kmem.failcnt);
-
-	for_each_mem_cgroup_tree(iter, memcg) {
-		pr_info("Memory cgroup stats for ");
-		pr_cont_cgroup_path(iter->css.cgroup);
-		pr_cont(":");
-
-		for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
-			if (memcg1_stats[i] == MEMCG_SWAP && !do_swap_account)
-				continue;
-			pr_cont(" %s:%luKB", memcg1_stat_names[i],
-				K(memcg_page_state(iter, memcg1_stats[i])));
-		}
-
-		for (i = 0; i < NR_LRU_LISTS; i++)
-			pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
-				K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
-
-		pr_cont("\n");
+	if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+		pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
+			K((u64)page_counter_read(&memcg->swap)),
+			K((u64)memcg->swap.max), memcg->swap.failcnt);
+	else {
+		pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
+			K((u64)page_counter_read(&memcg->memsw)),
+			K((u64)memcg->memsw.max), memcg->memsw.failcnt);
+		pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
+			K((u64)page_counter_read(&memcg->kmem)),
+			K((u64)memcg->kmem.max), memcg->kmem.failcnt);
 	}
+
+	pr_info("Memory cgroup stats for ");
+	pr_cont_cgroup_path(memcg->css.cgroup);
+	pr_cont(":");
+	buf = memory_stat_format(memcg);
+	if (!buf)
+		return;
+	pr_info("%s", buf);
+	kfree(buf);
 }
 
 /*
@@ -1370,6 +1567,11 @@
 	return max;
 }
 
+unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
+{
+	return page_counter_read(&memcg->memory);
+}
+
 static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
 				     int order)
 {
@@ -1382,8 +1584,13 @@
 	};
 	bool ret;
 
-	mutex_lock(&oom_lock);
-	ret = out_of_memory(&oc);
+	if (mutex_lock_killable(&oom_lock))
+		return true;
+	/*
+	 * A few threads which were not waiting at mutex_lock_killable() can
+	 * fail to bail out. Therefore, check again after holding oom_lock.
+	 */
+	ret = should_force_charge() || out_of_memory(&oc);
 	mutex_unlock(&oom_lock);
 	return ret;
 }
@@ -1403,11 +1610,15 @@
 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
 		int nid, bool noswap)
 {
-	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
+	struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
+
+	if (lruvec_page_state(lruvec, NR_INACTIVE_FILE) ||
+	    lruvec_page_state(lruvec, NR_ACTIVE_FILE))
 		return true;
 	if (noswap || !total_swap_pages)
 		return false;
-	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
+	if (lruvec_page_state(lruvec, NR_INACTIVE_ANON) ||
+	    lruvec_page_state(lruvec, NR_ACTIVE_ANON))
 		return true;
 	return false;
 
@@ -1666,9 +1877,14 @@
 
 static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
 {
+	enum oom_status ret;
+	bool locked;
+
 	if (order > PAGE_ALLOC_COSTLY_ORDER)
 		return OOM_SKIPPED;
 
+	memcg_memory_event(memcg, MEMCG_OOM);
+
 	/*
 	 * We are in the middle of the charge context here, so we
 	 * don't want to block when potentially sitting on a callstack
@@ -1698,10 +1914,23 @@
 		return OOM_ASYNC;
 	}
 
-	if (mem_cgroup_out_of_memory(memcg, mask, order))
-		return OOM_SUCCESS;
+	mem_cgroup_mark_under_oom(memcg);
 
-	return OOM_FAILED;
+	locked = mem_cgroup_oom_trylock(memcg);
+
+	if (locked)
+		mem_cgroup_oom_notify(memcg);
+
+	mem_cgroup_unmark_under_oom(memcg);
+	if (mem_cgroup_out_of_memory(memcg, mask, order))
+		ret = OOM_SUCCESS;
+	else
+		ret = OOM_FAILED;
+
+	if (locked)
+		mem_cgroup_oom_unlock(memcg);
+
+	return ret;
 }
 
 /**
@@ -2040,21 +2269,22 @@
 	for_each_online_cpu(cpu) {
 		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
 		struct mem_cgroup *memcg;
+		bool flush = false;
 
+		rcu_read_lock();
 		memcg = stock->cached;
-		if (!memcg || !stock->nr_pages || !css_tryget(&memcg->css))
-			continue;
-		if (!mem_cgroup_is_descendant(memcg, root_memcg)) {
-			css_put(&memcg->css);
-			continue;
-		}
-		if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
+		if (memcg && stock->nr_pages &&
+		    mem_cgroup_is_descendant(memcg, root_memcg))
+			flush = true;
+		rcu_read_unlock();
+
+		if (flush &&
+		    !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
 			if (cpu == curcpu)
 				drain_local_stock(&stock->work);
 			else
 				schedule_work_on(cpu, &stock->work);
 		}
-		css_put(&memcg->css);
 	}
 	put_cpu();
 	mutex_unlock(&percpu_charge_mutex);
@@ -2063,7 +2293,7 @@
 static int memcg_hotplug_cpu_dead(unsigned int cpu)
 {
 	struct memcg_stock_pcp *stock;
-	struct mem_cgroup *memcg;
+	struct mem_cgroup *memcg, *mi;
 
 	stock = &per_cpu(memcg_stock, cpu);
 	drain_stock(stock);
@@ -2075,9 +2305,10 @@
 			int nid;
 			long x;
 
-			x = this_cpu_xchg(memcg->stat_cpu->count[i], 0);
+			x = this_cpu_xchg(memcg->vmstats_percpu->stat[i], 0);
 			if (x)
-				atomic_long_add(x, &memcg->stat[i]);
+				for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+					atomic_long_add(x, &memcg->vmstats[i]);
 
 			if (i >= NR_VM_NODE_STAT_ITEMS)
 				continue;
@@ -2088,16 +2319,19 @@
 				pn = mem_cgroup_nodeinfo(memcg, nid);
 				x = this_cpu_xchg(pn->lruvec_stat_cpu->count[i], 0);
 				if (x)
-					atomic_long_add(x, &pn->lruvec_stat[i]);
+					do {
+						atomic_long_add(x, &pn->lruvec_stat[i]);
+					} while ((pn = parent_nodeinfo(pn, nid)));
 			}
 		}
 
 		for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
 			long x;
 
-			x = this_cpu_xchg(memcg->stat_cpu->events[i], 0);
+			x = this_cpu_xchg(memcg->vmstats_percpu->events[i], 0);
 			if (x)
-				atomic_long_add(x, &memcg->events[i]);
+				for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+					atomic_long_add(x, &memcg->vmevents[i]);
 		}
 	}
 
@@ -2125,11 +2359,67 @@
 }
 
 /*
+ * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
+ * enough to still cause a significant slowdown in most cases, while still
+ * allowing diagnostics and tracing to proceed without becoming stuck.
+ */
+#define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
+
+/*
+ * When calculating the delay, we use these either side of the exponentiation to
+ * maintain precision and scale to a reasonable number of jiffies (see the table
+ * below.
+ *
+ * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
+ *   overage ratio to a delay.
+ * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down down the
+ *   proposed penalty in order to reduce to a reasonable number of jiffies, and
+ *   to produce a reasonable delay curve.
+ *
+ * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
+ * reasonable delay curve compared to precision-adjusted overage, not
+ * penalising heavily at first, but still making sure that growth beyond the
+ * limit penalises misbehaviour cgroups by slowing them down exponentially. For
+ * example, with a high of 100 megabytes:
+ *
+ *  +-------+------------------------+
+ *  | usage | time to allocate in ms |
+ *  +-------+------------------------+
+ *  | 100M  |                      0 |
+ *  | 101M  |                      6 |
+ *  | 102M  |                     25 |
+ *  | 103M  |                     57 |
+ *  | 104M  |                    102 |
+ *  | 105M  |                    159 |
+ *  | 106M  |                    230 |
+ *  | 107M  |                    313 |
+ *  | 108M  |                    409 |
+ *  | 109M  |                    518 |
+ *  | 110M  |                    639 |
+ *  | 111M  |                    774 |
+ *  | 112M  |                    921 |
+ *  | 113M  |                   1081 |
+ *  | 114M  |                   1254 |
+ *  | 115M  |                   1439 |
+ *  | 116M  |                   1638 |
+ *  | 117M  |                   1849 |
+ *  | 118M  |                   2000 |
+ *  | 119M  |                   2000 |
+ *  | 120M  |                   2000 |
+ *  +-------+------------------------+
+ */
+ #define MEMCG_DELAY_PRECISION_SHIFT 20
+ #define MEMCG_DELAY_SCALING_SHIFT 14
+
+/*
  * Scheduled by try_charge() to be executed from the userland return path
  * and reclaims memory over the high limit.
  */
 void mem_cgroup_handle_over_high(void)
 {
+	unsigned long usage, high, clamped_high;
+	unsigned long pflags;
+	unsigned long penalty_jiffies, overage;
 	unsigned int nr_pages = current->memcg_nr_pages_over_high;
 	struct mem_cgroup *memcg;
 
@@ -2138,8 +2428,75 @@
 
 	memcg = get_mem_cgroup_from_mm(current->mm);
 	reclaim_high(memcg, nr_pages, GFP_KERNEL);
-	css_put(&memcg->css);
 	current->memcg_nr_pages_over_high = 0;
+
+	/*
+	 * memory.high is breached and reclaim is unable to keep up. Throttle
+	 * allocators proactively to slow down excessive growth.
+	 *
+	 * We use overage compared to memory.high to calculate the number of
+	 * jiffies to sleep (penalty_jiffies). Ideally this value should be
+	 * fairly lenient on small overages, and increasingly harsh when the
+	 * memcg in question makes it clear that it has no intention of stopping
+	 * its crazy behaviour, so we exponentially increase the delay based on
+	 * overage amount.
+	 */
+
+	usage = page_counter_read(&memcg->memory);
+	high = READ_ONCE(memcg->high);
+
+	if (usage <= high)
+		goto out;
+
+	/*
+	 * Prevent division by 0 in overage calculation by acting as if it was a
+	 * threshold of 1 page
+	 */
+	clamped_high = max(high, 1UL);
+
+	overage = div_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT,
+			  clamped_high);
+
+	penalty_jiffies = ((u64)overage * overage * HZ)
+		>> (MEMCG_DELAY_PRECISION_SHIFT + MEMCG_DELAY_SCALING_SHIFT);
+
+	/*
+	 * Factor in the task's own contribution to the overage, such that four
+	 * N-sized allocations are throttled approximately the same as one
+	 * 4N-sized allocation.
+	 *
+	 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
+	 * larger the current charge patch is than that.
+	 */
+	penalty_jiffies = penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
+
+	/*
+	 * Clamp the max delay per usermode return so as to still keep the
+	 * application moving forwards and also permit diagnostics, albeit
+	 * extremely slowly.
+	 */
+	penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
+
+	/*
+	 * Don't sleep if the amount of jiffies this memcg owes us is so low
+	 * that it's not even worth doing, in an attempt to be nice to those who
+	 * go only a small amount over their memory.high value and maybe haven't
+	 * been aggressively reclaimed enough yet.
+	 */
+	if (penalty_jiffies <= HZ / 100)
+		goto out;
+
+	/*
+	 * If we exit early, we're guaranteed to die (since
+	 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
+	 * need to account for any ill-begotten jiffies to pay them off later.
+	 */
+	psi_memstall_enter(&pflags);
+	schedule_timeout_killable(penalty_jiffies);
+	psi_memstall_leave(&pflags);
+
+out:
+	css_put(&memcg->css);
 }
 
 static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
@@ -2152,7 +2509,6 @@
 	unsigned long nr_reclaimed;
 	bool may_swap = true;
 	bool drained = false;
-	bool oomed = false;
 	enum oom_status oom_status;
 
 	if (mem_cgroup_is_root(memcg))
@@ -2179,14 +2535,21 @@
 	}
 
 	/*
+	 * Memcg doesn't have a dedicated reserve for atomic
+	 * allocations. But like the global atomic pool, we need to
+	 * put the burden of reclaim on regular allocation requests
+	 * and let these go through as privileged allocations.
+	 */
+	if (gfp_mask & __GFP_ATOMIC)
+		goto force;
+
+	/*
 	 * Unlike in global OOM situations, memcg is not in a physical
 	 * memory shortage.  Allow dying and OOM-killed tasks to
 	 * bypass the last charges so that they can exit quickly and
 	 * free their memory.
 	 */
-	if (unlikely(tsk_is_oom_victim(current) ||
-		     fatal_signal_pending(current) ||
-		     current->flags & PF_EXITING))
+	if (unlikely(should_force_charge()))
 		goto force;
 
 	/*
@@ -2241,7 +2604,7 @@
 	if (nr_retries--)
 		goto retry;
 
-	if (gfp_mask & __GFP_RETRY_MAYFAIL && oomed)
+	if (gfp_mask & __GFP_RETRY_MAYFAIL)
 		goto nomem;
 
 	if (gfp_mask & __GFP_NOFAIL)
@@ -2250,8 +2613,6 @@
 	if (fatal_signal_pending(current))
 		goto force;
 
-	memcg_memory_event(mem_over_limit, MEMCG_OOM);
-
 	/*
 	 * keep retrying as long as the memcg oom killer is able to make
 	 * a forward progress or bypass the charge if the oom killer
@@ -2262,7 +2623,6 @@
 	switch (oom_status) {
 	case OOM_SUCCESS:
 		nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
-		oomed = true;
 		goto retry;
 	case OOM_FAILED:
 		goto force;
@@ -2329,13 +2689,13 @@
 
 static void lock_page_lru(struct page *page, int *isolated)
 {
-	struct zone *zone = page_zone(page);
+	pg_data_t *pgdat = page_pgdat(page);
 
-	spin_lock_irq(zone_lru_lock(zone));
+	spin_lock_irq(&pgdat->lru_lock);
 	if (PageLRU(page)) {
 		struct lruvec *lruvec;
 
-		lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		ClearPageLRU(page);
 		del_page_from_lru_list(page, lruvec, page_lru(page));
 		*isolated = 1;
@@ -2345,17 +2705,17 @@
 
 static void unlock_page_lru(struct page *page, int isolated)
 {
-	struct zone *zone = page_zone(page);
+	pg_data_t *pgdat = page_pgdat(page);
 
 	if (isolated) {
 		struct lruvec *lruvec;
 
-		lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		SetPageLRU(page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
 	}
-	spin_unlock_irq(zone_lru_lock(zone));
+	spin_unlock_irq(&pgdat->lru_lock);
 }
 
 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
@@ -2460,17 +2820,18 @@
 /*
  * Enqueue the creation of a per-memcg kmem_cache.
  */
-static void __memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
+static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
 					       struct kmem_cache *cachep)
 {
 	struct memcg_kmem_cache_create_work *cw;
 
+	if (!css_tryget_online(&memcg->css))
+		return;
+
 	cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
 	if (!cw)
 		return;
 
-	css_get(&memcg->css);
-
 	cw->memcg = memcg;
 	cw->cachep = cachep;
 	INIT_WORK(&cw->work, memcg_kmem_cache_create_func);
@@ -2478,25 +2839,6 @@
 	queue_work(memcg_kmem_cache_wq, &cw->work);
 }
 
-static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
-					     struct kmem_cache *cachep)
-{
-	/*
-	 * We need to stop accounting when we kmalloc, because if the
-	 * corresponding kmalloc cache is not yet created, the first allocation
-	 * in __memcg_schedule_kmem_cache_create will recurse.
-	 *
-	 * However, it is better to enclose the whole function. Depending on
-	 * the debugging options enabled, INIT_WORK(), for instance, can
-	 * trigger an allocation. This too, will make us recurse. Because at
-	 * this point we can't allow ourselves back into memcg_kmem_get_cache,
-	 * the safest choice is to do it like this, wrapping the whole function.
-	 */
-	current->memcg_kmem_skip_account = 1;
-	__memcg_schedule_kmem_cache_create(memcg, cachep);
-	current->memcg_kmem_skip_account = 0;
-}
-
 static inline bool memcg_kmem_bypass(void)
 {
 	if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
@@ -2524,6 +2866,7 @@
 {
 	struct mem_cgroup *memcg;
 	struct kmem_cache *memcg_cachep;
+	struct memcg_cache_array *arr;
 	int kmemcg_id;
 
 	VM_BUG_ON(!is_root_cache(cachep));
@@ -2531,17 +2874,28 @@
 	if (memcg_kmem_bypass())
 		return cachep;
 
-	if (current->memcg_kmem_skip_account)
-		return cachep;
+	rcu_read_lock();
 
-	memcg = get_mem_cgroup_from_current();
+	if (unlikely(current->active_memcg))
+		memcg = current->active_memcg;
+	else
+		memcg = mem_cgroup_from_task(current);
+
+	if (!memcg || memcg == root_mem_cgroup)
+		goto out_unlock;
+
 	kmemcg_id = READ_ONCE(memcg->kmemcg_id);
 	if (kmemcg_id < 0)
-		goto out;
+		goto out_unlock;
 
-	memcg_cachep = cache_from_memcg_idx(cachep, kmemcg_id);
-	if (likely(memcg_cachep))
-		return memcg_cachep;
+	arr = rcu_dereference(cachep->memcg_params.memcg_caches);
+
+	/*
+	 * Make sure we will access the up-to-date value. The code updating
+	 * memcg_caches issues a write barrier to match the data dependency
+	 * barrier inside READ_ONCE() (see memcg_create_kmem_cache()).
+	 */
+	memcg_cachep = READ_ONCE(arr->entries[kmemcg_id]);
 
 	/*
 	 * If we are in a safe context (can wait, and not in interrupt
@@ -2554,10 +2908,20 @@
 	 * memcg_create_kmem_cache, this means no further allocation
 	 * could happen with the slab_mutex held. So it's better to
 	 * defer everything.
+	 *
+	 * If the memcg is dying or memcg_cache is about to be released,
+	 * don't bother creating new kmem_caches. Because memcg_cachep
+	 * is ZEROed as the fist step of kmem offlining, we don't need
+	 * percpu_ref_tryget_live() here. css_tryget_online() check in
+	 * memcg_schedule_kmem_cache_create() will prevent us from
+	 * creation of a new kmem_cache.
 	 */
-	memcg_schedule_kmem_cache_create(memcg, cachep);
-out:
-	css_put(&memcg->css);
+	if (unlikely(!memcg_cachep))
+		memcg_schedule_kmem_cache_create(memcg, cachep);
+	else if (percpu_ref_tryget(&memcg_cachep->memcg_params.refcnt))
+		cachep = memcg_cachep;
+out_unlock:
+	rcu_read_unlock();
 	return cachep;
 }
 
@@ -2568,11 +2932,11 @@
 void memcg_kmem_put_cache(struct kmem_cache *cachep)
 {
 	if (!is_root_cache(cachep))
-		css_put(&cachep->memcg_params.memcg->css);
+		percpu_ref_put(&cachep->memcg_params.refcnt);
 }
 
 /**
- * memcg_kmem_charge_memcg: charge a kmem page
+ * __memcg_kmem_charge_memcg: charge a kmem page
  * @page: page to charge
  * @gfp: reclaim mode
  * @order: allocation order
@@ -2580,7 +2944,7 @@
  *
  * Returns 0 on success, an error code on failure.
  */
-int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
+int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
 			    struct mem_cgroup *memcg)
 {
 	unsigned int nr_pages = 1 << order;
@@ -2593,24 +2957,31 @@
 
 	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
 	    !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) {
+
+		/*
+		 * Enforce __GFP_NOFAIL allocation because callers are not
+		 * prepared to see failures and likely do not have any failure
+		 * handling code.
+		 */
+		if (gfp & __GFP_NOFAIL) {
+			page_counter_charge(&memcg->kmem, nr_pages);
+			return 0;
+		}
 		cancel_charge(memcg, nr_pages);
 		return -ENOMEM;
 	}
-
-	page->mem_cgroup = memcg;
-
 	return 0;
 }
 
 /**
- * memcg_kmem_charge: charge a kmem page to the current memory cgroup
+ * __memcg_kmem_charge: charge a kmem page to the current memory cgroup
  * @page: page to charge
  * @gfp: reclaim mode
  * @order: allocation order
  *
  * Returns 0 on success, an error code on failure.
  */
-int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
+int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
 {
 	struct mem_cgroup *memcg;
 	int ret = 0;
@@ -2620,19 +2991,37 @@
 
 	memcg = get_mem_cgroup_from_current();
 	if (!mem_cgroup_is_root(memcg)) {
-		ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
-		if (!ret)
+		ret = __memcg_kmem_charge_memcg(page, gfp, order, memcg);
+		if (!ret) {
+			page->mem_cgroup = memcg;
 			__SetPageKmemcg(page);
+		}
 	}
 	css_put(&memcg->css);
 	return ret;
 }
+
 /**
- * memcg_kmem_uncharge: uncharge a kmem page
+ * __memcg_kmem_uncharge_memcg: uncharge a kmem page
+ * @memcg: memcg to uncharge
+ * @nr_pages: number of pages to uncharge
+ */
+void __memcg_kmem_uncharge_memcg(struct mem_cgroup *memcg,
+				 unsigned int nr_pages)
+{
+	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+		page_counter_uncharge(&memcg->kmem, nr_pages);
+
+	page_counter_uncharge(&memcg->memory, nr_pages);
+	if (do_memsw_account())
+		page_counter_uncharge(&memcg->memsw, nr_pages);
+}
+/**
+ * __memcg_kmem_uncharge: uncharge a kmem page
  * @page: page to uncharge
  * @order: allocation order
  */
-void memcg_kmem_uncharge(struct page *page, int order)
+void __memcg_kmem_uncharge(struct page *page, int order)
 {
 	struct mem_cgroup *memcg = page->mem_cgroup;
 	unsigned int nr_pages = 1 << order;
@@ -2641,14 +3030,7 @@
 		return;
 
 	VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
-
-	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
-		page_counter_uncharge(&memcg->kmem, nr_pages);
-
-	page_counter_uncharge(&memcg->memory, nr_pages);
-	if (do_memsw_account())
-		page_counter_uncharge(&memcg->memsw, nr_pages);
-
+	__memcg_kmem_uncharge_memcg(memcg, nr_pages);
 	page->mem_cgroup = NULL;
 
 	/* slab pages do not have PageKmemcg flag set */
@@ -2663,7 +3045,7 @@
 
 /*
  * Because tail pages are not marked as "used", set it. We're under
- * zone_lru_lock and migration entries setup in all page mappings.
+ * pgdat->lru_lock and migration entries setup in all page mappings.
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
 {
@@ -2953,50 +3335,15 @@
 	return retval;
 }
 
-struct accumulated_stats {
-	unsigned long stat[MEMCG_NR_STAT];
-	unsigned long events[NR_VM_EVENT_ITEMS];
-	unsigned long lru_pages[NR_LRU_LISTS];
-	const unsigned int *stats_array;
-	const unsigned int *events_array;
-	int stats_size;
-	int events_size;
-};
-
-static void accumulate_memcg_tree(struct mem_cgroup *memcg,
-				  struct accumulated_stats *acc)
-{
-	struct mem_cgroup *mi;
-	int i;
-
-	for_each_mem_cgroup_tree(mi, memcg) {
-		for (i = 0; i < acc->stats_size; i++)
-			acc->stat[i] += memcg_page_state(mi,
-				acc->stats_array ? acc->stats_array[i] : i);
-
-		for (i = 0; i < acc->events_size; i++)
-			acc->events[i] += memcg_sum_events(mi,
-				acc->events_array ? acc->events_array[i] : i);
-
-		for (i = 0; i < NR_LRU_LISTS; i++)
-			acc->lru_pages[i] +=
-				mem_cgroup_nr_lru_pages(mi, BIT(i));
-	}
-}
-
 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
 {
-	unsigned long val = 0;
+	unsigned long val;
 
 	if (mem_cgroup_is_root(memcg)) {
-		struct mem_cgroup *iter;
-
-		for_each_mem_cgroup_tree(iter, memcg) {
-			val += memcg_page_state(iter, MEMCG_CACHE);
-			val += memcg_page_state(iter, MEMCG_RSS);
-			if (swap)
-				val += memcg_page_state(iter, MEMCG_SWAP);
-		}
+		val = memcg_page_state(memcg, MEMCG_CACHE) +
+			memcg_page_state(memcg, MEMCG_RSS);
+		if (swap)
+			val += memcg_page_state(memcg, MEMCG_SWAP);
 	} else {
 		if (!swap)
 			val = page_counter_read(&memcg->memory);
@@ -3057,6 +3404,72 @@
 	}
 }
 
+static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg, bool slab_only)
+{
+	unsigned long stat[MEMCG_NR_STAT];
+	struct mem_cgroup *mi;
+	int node, cpu, i;
+	int min_idx, max_idx;
+
+	if (slab_only) {
+		min_idx = NR_SLAB_RECLAIMABLE;
+		max_idx = NR_SLAB_UNRECLAIMABLE;
+	} else {
+		min_idx = 0;
+		max_idx = MEMCG_NR_STAT;
+	}
+
+	for (i = min_idx; i < max_idx; i++)
+		stat[i] = 0;
+
+	for_each_online_cpu(cpu)
+		for (i = min_idx; i < max_idx; i++)
+			stat[i] += per_cpu(memcg->vmstats_percpu->stat[i], cpu);
+
+	for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+		for (i = min_idx; i < max_idx; i++)
+			atomic_long_add(stat[i], &mi->vmstats[i]);
+
+	if (!slab_only)
+		max_idx = NR_VM_NODE_STAT_ITEMS;
+
+	for_each_node(node) {
+		struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
+		struct mem_cgroup_per_node *pi;
+
+		for (i = min_idx; i < max_idx; i++)
+			stat[i] = 0;
+
+		for_each_online_cpu(cpu)
+			for (i = min_idx; i < max_idx; i++)
+				stat[i] += per_cpu(
+					pn->lruvec_stat_cpu->count[i], cpu);
+
+		for (pi = pn; pi; pi = parent_nodeinfo(pi, node))
+			for (i = min_idx; i < max_idx; i++)
+				atomic_long_add(stat[i], &pi->lruvec_stat[i]);
+	}
+}
+
+static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg)
+{
+	unsigned long events[NR_VM_EVENT_ITEMS];
+	struct mem_cgroup *mi;
+	int cpu, i;
+
+	for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+		events[i] = 0;
+
+	for_each_online_cpu(cpu)
+		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+			events[i] += per_cpu(memcg->vmstats_percpu->events[i],
+					     cpu);
+
+	for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+			atomic_long_add(events[i], &mi->vmevents[i]);
+}
+
 #ifdef CONFIG_MEMCG_KMEM
 static int memcg_online_kmem(struct mem_cgroup *memcg)
 {
@@ -3102,16 +3515,23 @@
 	 */
 	memcg->kmem_state = KMEM_ALLOCATED;
 
-	memcg_deactivate_kmem_caches(memcg);
-
-	kmemcg_id = memcg->kmemcg_id;
-	BUG_ON(kmemcg_id < 0);
-
 	parent = parent_mem_cgroup(memcg);
 	if (!parent)
 		parent = root_mem_cgroup;
 
 	/*
+	 * Deactivate and reparent kmem_caches. Then flush percpu
+	 * slab statistics to have precise values at the parent and
+	 * all ancestor levels. It's required to keep slab stats
+	 * accurate after the reparenting of kmem_caches.
+	 */
+	memcg_deactivate_kmem_caches(memcg, parent);
+	memcg_flush_percpu_vmstats(memcg, true);
+
+	kmemcg_id = memcg->kmemcg_id;
+	BUG_ON(kmemcg_id < 0);
+
+	/*
 	 * Change kmemcg_id of this cgroup and all its descendants to the
 	 * parent's id, and then move all entries from this cgroup's list_lrus
 	 * to ones of the parent. After we have finished, all list_lrus
@@ -3141,9 +3561,8 @@
 		memcg_offline_kmem(memcg);
 
 	if (memcg->kmem_state == KMEM_ALLOCATED) {
-		memcg_destroy_kmem_caches(memcg);
+		WARN_ON(!list_empty(&memcg->kmem_caches));
 		static_branch_dec(&memcg_kmem_enabled_key);
-		WARN_ON(page_counter_read(&memcg->kmem));
 	}
 }
 #else
@@ -3235,6 +3654,9 @@
 			ret = mem_cgroup_resize_max(memcg, nr_pages, true);
 			break;
 		case _KMEM:
+			pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
+				     "Please report your usecase to linux-mm@kvack.org if you "
+				     "depend on this functionality.\n");
 			ret = memcg_update_kmem_max(memcg, nr_pages);
 			break;
 		case _TCP:
@@ -3320,6 +3742,42 @@
 #endif
 
 #ifdef CONFIG_NUMA
+
+#define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
+#define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
+#define LRU_ALL	     ((1 << NR_LRU_LISTS) - 1)
+
+static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
+					   int nid, unsigned int lru_mask)
+{
+	struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
+	unsigned long nr = 0;
+	enum lru_list lru;
+
+	VM_BUG_ON((unsigned)nid >= nr_node_ids);
+
+	for_each_lru(lru) {
+		if (!(BIT(lru) & lru_mask))
+			continue;
+		nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
+	}
+	return nr;
+}
+
+static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
+					     unsigned int lru_mask)
+{
+	unsigned long nr = 0;
+	enum lru_list lru;
+
+	for_each_lru(lru) {
+		if (!(BIT(lru) & lru_mask))
+			continue;
+		nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru);
+	}
+	return nr;
+}
+
 static int memcg_numa_stat_show(struct seq_file *m, void *v)
 {
 	struct numa_stat {
@@ -3336,7 +3794,7 @@
 	const struct numa_stat *stat;
 	int nid;
 	unsigned long nr;
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
 
 	for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
 		nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
@@ -3370,6 +3828,28 @@
 }
 #endif /* CONFIG_NUMA */
 
+static const unsigned int memcg1_stats[] = {
+	MEMCG_CACHE,
+	MEMCG_RSS,
+	MEMCG_RSS_HUGE,
+	NR_SHMEM,
+	NR_FILE_MAPPED,
+	NR_FILE_DIRTY,
+	NR_WRITEBACK,
+	MEMCG_SWAP,
+};
+
+static const char *const memcg1_stat_names[] = {
+	"cache",
+	"rss",
+	"rss_huge",
+	"shmem",
+	"mapped_file",
+	"dirty",
+	"writeback",
+	"swap",
+};
+
 /* Universal VM events cgroup1 shows, original sort order */
 static const unsigned int memcg1_events[] = {
 	PGPGIN,
@@ -3387,11 +3867,10 @@
 
 static int memcg_stat_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
 	unsigned long memory, memsw;
 	struct mem_cgroup *mi;
 	unsigned int i;
-	struct accumulated_stats acc;
 
 	BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
 	BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
@@ -3400,17 +3879,18 @@
 		if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
 			continue;
 		seq_printf(m, "%s %lu\n", memcg1_stat_names[i],
-			   memcg_page_state(memcg, memcg1_stats[i]) *
+			   memcg_page_state_local(memcg, memcg1_stats[i]) *
 			   PAGE_SIZE);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
 		seq_printf(m, "%s %lu\n", memcg1_event_names[i],
-			   memcg_sum_events(memcg, memcg1_events[i]));
+			   memcg_events_local(memcg, memcg1_events[i]));
 
 	for (i = 0; i < NR_LRU_LISTS; i++)
 		seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
-			   mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
+			   memcg_page_state_local(memcg, NR_LRU_BASE + i) *
+			   PAGE_SIZE);
 
 	/* Hierarchical information */
 	memory = memsw = PAGE_COUNTER_MAX;
@@ -3424,27 +3904,22 @@
 		seq_printf(m, "hierarchical_memsw_limit %llu\n",
 			   (u64)memsw * PAGE_SIZE);
 
-	memset(&acc, 0, sizeof(acc));
-	acc.stats_size = ARRAY_SIZE(memcg1_stats);
-	acc.stats_array = memcg1_stats;
-	acc.events_size = ARRAY_SIZE(memcg1_events);
-	acc.events_array = memcg1_events;
-	accumulate_memcg_tree(memcg, &acc);
-
 	for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
 		if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
 			continue;
 		seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
-			   (u64)acc.stat[i] * PAGE_SIZE);
+			   (u64)memcg_page_state(memcg, memcg1_stats[i]) *
+			   PAGE_SIZE);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
 		seq_printf(m, "total_%s %llu\n", memcg1_event_names[i],
-			   (u64)acc.events[i]);
+			   (u64)memcg_events(memcg, memcg1_events[i]));
 
 	for (i = 0; i < NR_LRU_LISTS; i++)
 		seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i],
-			   (u64)acc.lru_pages[i] * PAGE_SIZE);
+			   (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
+			   PAGE_SIZE);
 
 #ifdef CONFIG_DEBUG_VM
 	{
@@ -3625,8 +4100,7 @@
 	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
 
 	/* Allocate memory for new array of thresholds */
-	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
-			GFP_KERNEL);
+	new = kmalloc(struct_size(new, entries, size), GFP_KERNEL);
 	if (!new) {
 		ret = -ENOMEM;
 		goto unlock;
@@ -3820,7 +4294,7 @@
 
 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(sf);
 
 	seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
 	seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
@@ -3847,6 +4321,8 @@
 
 #ifdef CONFIG_CGROUP_WRITEBACK
 
+#include <trace/events/writeback.h>
+
 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
 {
 	return wb_domain_init(&memcg->cgwb_domain, gfp);
@@ -3872,6 +4348,22 @@
 	return &memcg->cgwb_domain;
 }
 
+/*
+ * idx can be of type enum memcg_stat_item or node_stat_item.
+ * Keep in sync with memcg_exact_page().
+ */
+static unsigned long memcg_exact_page_state(struct mem_cgroup *memcg, int idx)
+{
+	long x = atomic_long_read(&memcg->vmstats[idx]);
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		x += per_cpu_ptr(memcg->vmstats_percpu, cpu)->stat[idx];
+	if (x < 0)
+		x = 0;
+	return x;
+}
+
 /**
  * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
  * @wb: bdi_writeback in question
@@ -3897,12 +4389,12 @@
 	struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
 	struct mem_cgroup *parent;
 
-	*pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
+	*pdirty = memcg_exact_page_state(memcg, NR_FILE_DIRTY);
 
 	/* this should eventually include NR_UNSTABLE_NFS */
-	*pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
-	*pfilepages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
-						     (1 << LRU_ACTIVE_FILE));
+	*pwriteback = memcg_exact_page_state(memcg, NR_WRITEBACK);
+	*pfilepages = memcg_exact_page_state(memcg, NR_INACTIVE_FILE) +
+			memcg_exact_page_state(memcg, NR_ACTIVE_FILE);
 	*pheadroom = PAGE_COUNTER_MAX;
 
 	while ((parent = parent_mem_cgroup(memcg))) {
@@ -3914,6 +4406,130 @@
 	}
 }
 
+/*
+ * Foreign dirty flushing
+ *
+ * There's an inherent mismatch between memcg and writeback.  The former
+ * trackes ownership per-page while the latter per-inode.  This was a
+ * deliberate design decision because honoring per-page ownership in the
+ * writeback path is complicated, may lead to higher CPU and IO overheads
+ * and deemed unnecessary given that write-sharing an inode across
+ * different cgroups isn't a common use-case.
+ *
+ * Combined with inode majority-writer ownership switching, this works well
+ * enough in most cases but there are some pathological cases.  For
+ * example, let's say there are two cgroups A and B which keep writing to
+ * different but confined parts of the same inode.  B owns the inode and
+ * A's memory is limited far below B's.  A's dirty ratio can rise enough to
+ * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
+ * triggering background writeback.  A will be slowed down without a way to
+ * make writeback of the dirty pages happen.
+ *
+ * Conditions like the above can lead to a cgroup getting repatedly and
+ * severely throttled after making some progress after each
+ * dirty_expire_interval while the underyling IO device is almost
+ * completely idle.
+ *
+ * Solving this problem completely requires matching the ownership tracking
+ * granularities between memcg and writeback in either direction.  However,
+ * the more egregious behaviors can be avoided by simply remembering the
+ * most recent foreign dirtying events and initiating remote flushes on
+ * them when local writeback isn't enough to keep the memory clean enough.
+ *
+ * The following two functions implement such mechanism.  When a foreign
+ * page - a page whose memcg and writeback ownerships don't match - is
+ * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
+ * bdi_writeback on the page owning memcg.  When balance_dirty_pages()
+ * decides that the memcg needs to sleep due to high dirty ratio, it calls
+ * mem_cgroup_flush_foreign() which queues writeback on the recorded
+ * foreign bdi_writebacks which haven't expired.  Both the numbers of
+ * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
+ * limited to MEMCG_CGWB_FRN_CNT.
+ *
+ * The mechanism only remembers IDs and doesn't hold any object references.
+ * As being wrong occasionally doesn't matter, updates and accesses to the
+ * records are lockless and racy.
+ */
+void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
+					     struct bdi_writeback *wb)
+{
+	struct mem_cgroup *memcg = page->mem_cgroup;
+	struct memcg_cgwb_frn *frn;
+	u64 now = get_jiffies_64();
+	u64 oldest_at = now;
+	int oldest = -1;
+	int i;
+
+	trace_track_foreign_dirty(page, wb);
+
+	/*
+	 * Pick the slot to use.  If there is already a slot for @wb, keep
+	 * using it.  If not replace the oldest one which isn't being
+	 * written out.
+	 */
+	for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
+		frn = &memcg->cgwb_frn[i];
+		if (frn->bdi_id == wb->bdi->id &&
+		    frn->memcg_id == wb->memcg_css->id)
+			break;
+		if (time_before64(frn->at, oldest_at) &&
+		    atomic_read(&frn->done.cnt) == 1) {
+			oldest = i;
+			oldest_at = frn->at;
+		}
+	}
+
+	if (i < MEMCG_CGWB_FRN_CNT) {
+		/*
+		 * Re-using an existing one.  Update timestamp lazily to
+		 * avoid making the cacheline hot.  We want them to be
+		 * reasonably up-to-date and significantly shorter than
+		 * dirty_expire_interval as that's what expires the record.
+		 * Use the shorter of 1s and dirty_expire_interval / 8.
+		 */
+		unsigned long update_intv =
+			min_t(unsigned long, HZ,
+			      msecs_to_jiffies(dirty_expire_interval * 10) / 8);
+
+		if (time_before64(frn->at, now - update_intv))
+			frn->at = now;
+	} else if (oldest >= 0) {
+		/* replace the oldest free one */
+		frn = &memcg->cgwb_frn[oldest];
+		frn->bdi_id = wb->bdi->id;
+		frn->memcg_id = wb->memcg_css->id;
+		frn->at = now;
+	}
+}
+
+/* issue foreign writeback flushes for recorded foreign dirtying events */
+void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+	unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10);
+	u64 now = jiffies_64;
+	int i;
+
+	for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
+		struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i];
+
+		/*
+		 * If the record is older than dirty_expire_interval,
+		 * writeback on it has already started.  No need to kick it
+		 * off again.  Also, don't start a new one if there's
+		 * already one in flight.
+		 */
+		if (time_after64(frn->at, now - intv) &&
+		    atomic_read(&frn->done.cnt) == 1) {
+			frn->at = 0;
+			trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
+			cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id, 0,
+					       WB_REASON_FOREIGN_FLUSH,
+					       &frn->done);
+		}
+	}
+}
+
 #else	/* CONFIG_CGROUP_WRITEBACK */
 
 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
@@ -4321,14 +4937,12 @@
 
 static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
 {
-	VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
-	atomic_add(n, &memcg->id.ref);
+	refcount_add(n, &memcg->id.ref);
 }
 
 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
 {
-	VM_BUG_ON(atomic_read(&memcg->id.ref) < n);
-	if (atomic_sub_and_test(n, &memcg->id.ref)) {
+	if (refcount_sub_and_test(n, &memcg->id.ref)) {
 		mem_cgroup_id_remove(memcg);
 
 		/* Memcg ID pins CSS */
@@ -4336,11 +4950,6 @@
 	}
 }
 
-static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
-{
-	mem_cgroup_id_get_many(memcg, 1);
-}
-
 static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
 {
 	mem_cgroup_id_put_many(memcg, 1);
@@ -4376,8 +4985,15 @@
 	if (!pn)
 		return 1;
 
+	pn->lruvec_stat_local = alloc_percpu(struct lruvec_stat);
+	if (!pn->lruvec_stat_local) {
+		kfree(pn);
+		return 1;
+	}
+
 	pn->lruvec_stat_cpu = alloc_percpu(struct lruvec_stat);
 	if (!pn->lruvec_stat_cpu) {
+		free_percpu(pn->lruvec_stat_local);
 		kfree(pn);
 		return 1;
 	}
@@ -4399,6 +5015,7 @@
 		return;
 
 	free_percpu(pn->lruvec_stat_cpu);
+	free_percpu(pn->lruvec_stat_local);
 	kfree(pn);
 }
 
@@ -4408,21 +5025,29 @@
 
 	for_each_node(node)
 		free_mem_cgroup_per_node_info(memcg, node);
-	free_percpu(memcg->stat_cpu);
+	free_percpu(memcg->vmstats_percpu);
+	free_percpu(memcg->vmstats_local);
 	kfree(memcg);
 }
 
 static void mem_cgroup_free(struct mem_cgroup *memcg)
 {
 	memcg_wb_domain_exit(memcg);
+	/*
+	 * Flush percpu vmstats and vmevents to guarantee the value correctness
+	 * on parent's and all ancestor levels.
+	 */
+	memcg_flush_percpu_vmstats(memcg, false);
+	memcg_flush_percpu_vmevents(memcg);
 	__mem_cgroup_free(memcg);
 }
 
 static struct mem_cgroup *mem_cgroup_alloc(void)
 {
 	struct mem_cgroup *memcg;
-	size_t size;
+	unsigned int size;
 	int node;
+	int __maybe_unused i;
 
 	size = sizeof(struct mem_cgroup);
 	size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
@@ -4437,8 +5062,12 @@
 	if (memcg->id.id < 0)
 		goto fail;
 
-	memcg->stat_cpu = alloc_percpu(struct mem_cgroup_stat_cpu);
-	if (!memcg->stat_cpu)
+	memcg->vmstats_local = alloc_percpu(struct memcg_vmstats_percpu);
+	if (!memcg->vmstats_local)
+		goto fail;
+
+	memcg->vmstats_percpu = alloc_percpu(struct memcg_vmstats_percpu);
+	if (!memcg->vmstats_percpu)
 		goto fail;
 
 	for_each_node(node)
@@ -4462,6 +5091,14 @@
 #endif
 #ifdef CONFIG_CGROUP_WRITEBACK
 	INIT_LIST_HEAD(&memcg->cgwb_list);
+	for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
+		memcg->cgwb_frn[i].done =
+			__WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
+	INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
+	memcg->deferred_split_queue.split_queue_len = 0;
 #endif
 	idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
 	return memcg;
@@ -4512,6 +5149,9 @@
 
 	/* The following stuff does not apply to the root */
 	if (!parent) {
+#ifdef CONFIG_MEMCG_KMEM
+		INIT_LIST_HEAD(&memcg->kmem_caches);
+#endif
 		root_mem_cgroup = memcg;
 		return &memcg->css;
 	}
@@ -4545,7 +5185,7 @@
 	}
 
 	/* Online state pins memcg ID, memcg ID pins CSS */
-	atomic_set(&memcg->id.ref, 1);
+	refcount_set(&memcg->id.ref, 1);
 	css_get(css);
 	return 0;
 }
@@ -4573,6 +5213,8 @@
 	memcg_offline_kmem(memcg);
 	wb_memcg_offline(memcg);
 
+	drain_all_stock(memcg);
+
 	mem_cgroup_id_put(memcg);
 }
 
@@ -4586,7 +5228,12 @@
 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+	int __maybe_unused i;
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+	for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
+		wb_wait_for_completion(&memcg->cgwb_frn[i].done);
+#endif
 	if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
 		static_branch_dec(&memcg_sockets_enabled_key);
 
@@ -4669,7 +5316,7 @@
 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
 						unsigned long addr, pte_t ptent)
 {
-	struct page *page = _vm_normal_page(vma, addr, ptent, true);
+	struct page *page = vm_normal_page(vma, addr, ptent);
 
 	if (!page || !page_mapped(page))
 		return NULL;
@@ -4750,7 +5397,7 @@
 	/* shmem/tmpfs may report page out on swap: account for that too. */
 	if (shmem_mapping(mapping)) {
 		page = find_get_entry(mapping, pgoff);
-		if (radix_tree_exceptional_entry(page)) {
+		if (xa_is_value(page)) {
 			swp_entry_t swp = radix_to_swp_entry(page);
 			if (do_memsw_account())
 				*entry = swp;
@@ -4782,6 +5429,8 @@
 				   struct mem_cgroup *from,
 				   struct mem_cgroup *to)
 {
+	struct lruvec *from_vec, *to_vec;
+	struct pglist_data *pgdat;
 	unsigned long flags;
 	unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
 	int ret;
@@ -4805,11 +5454,15 @@
 
 	anon = PageAnon(page);
 
+	pgdat = page_pgdat(page);
+	from_vec = mem_cgroup_lruvec(pgdat, from);
+	to_vec = mem_cgroup_lruvec(pgdat, to);
+
 	spin_lock_irqsave(&from->move_lock, flags);
 
 	if (!anon && page_mapped(page)) {
-		__mod_memcg_state(from, NR_FILE_MAPPED, -nr_pages);
-		__mod_memcg_state(to, NR_FILE_MAPPED, nr_pages);
+		__mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
+		__mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
 	}
 
 	/*
@@ -4821,16 +5474,24 @@
 		struct address_space *mapping = page_mapping(page);
 
 		if (mapping_cap_account_dirty(mapping)) {
-			__mod_memcg_state(from, NR_FILE_DIRTY, -nr_pages);
-			__mod_memcg_state(to, NR_FILE_DIRTY, nr_pages);
+			__mod_lruvec_state(from_vec, NR_FILE_DIRTY, -nr_pages);
+			__mod_lruvec_state(to_vec, NR_FILE_DIRTY, nr_pages);
 		}
 	}
 
 	if (PageWriteback(page)) {
-		__mod_memcg_state(from, NR_WRITEBACK, -nr_pages);
-		__mod_memcg_state(to, NR_WRITEBACK, nr_pages);
+		__mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
+		__mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
 	}
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	if (compound && !list_empty(page_deferred_list(page))) {
+		spin_lock(&from->deferred_split_queue.split_queue_lock);
+		list_del_init(page_deferred_list(page));
+		from->deferred_split_queue.split_queue_len--;
+		spin_unlock(&from->deferred_split_queue.split_queue_lock);
+	}
+#endif
 	/*
 	 * It is safe to change page->mem_cgroup here because the page
 	 * is referenced, charged, and isolated - we can't race with
@@ -4839,6 +5500,17 @@
 
 	/* caller should have done css_get */
 	page->mem_cgroup = to;
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	if (compound && list_empty(page_deferred_list(page))) {
+		spin_lock(&to->deferred_split_queue.split_queue_lock);
+		list_add_tail(page_deferred_list(page),
+			      &to->deferred_split_queue.split_queue);
+		to->deferred_split_queue.split_queue_len++;
+		spin_unlock(&to->deferred_split_queue.split_queue_lock);
+	}
+#endif
+
 	spin_unlock_irqrestore(&from->move_lock, flags);
 
 	ret = 0;
@@ -4870,8 +5542,8 @@
  *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
  *     target for charge migration. if @target is not NULL, the entry is stored
  *     in target->ent.
- *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is MEMORY_DEVICE_PUBLIC
- *     or MEMORY_DEVICE_PRIVATE (so ZONE_DEVICE page and thus not on the lru).
+ *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is MEMORY_DEVICE_PRIVATE
+ *     (so ZONE_DEVICE page and thus not on the lru).
  *     For now we such page is charge like a regular page would be as for all
  *     intent and purposes it is just special memory taking the place of a
  *     regular page.
@@ -4905,8 +5577,7 @@
 		 */
 		if (page->mem_cgroup == mc.from) {
 			ret = MC_TARGET_PAGE;
-			if (is_device_private_page(page) ||
-			    is_device_public_page(page))
+			if (is_device_private_page(page))
 				ret = MC_TARGET_DEVICE;
 			if (target)
 				target->page = page;
@@ -4977,8 +5648,8 @@
 	if (ptl) {
 		/*
 		 * Note their can not be MC_TARGET_DEVICE for now as we do not
-		 * support transparent huge page with MEMORY_DEVICE_PUBLIC or
-		 * MEMORY_DEVICE_PRIVATE but this might change.
+		 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
+		 * this might change.
 		 */
 		if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
 			mc.precharge += HPAGE_PMD_NR;
@@ -4998,17 +5669,16 @@
 	return 0;
 }
 
+static const struct mm_walk_ops precharge_walk_ops = {
+	.pmd_entry	= mem_cgroup_count_precharge_pte_range,
+};
+
 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
 {
 	unsigned long precharge;
 
-	struct mm_walk mem_cgroup_count_precharge_walk = {
-		.pmd_entry = mem_cgroup_count_precharge_pte_range,
-		.mm = mm,
-	};
 	down_read(&mm->mmap_sem);
-	walk_page_range(0, mm->highest_vm_end,
-			&mem_cgroup_count_precharge_walk);
+	walk_page_range(mm, 0, mm->highest_vm_end, &precharge_walk_ops, NULL);
 	up_read(&mm->mmap_sem);
 
 	precharge = mc.precharge;
@@ -5277,13 +5947,12 @@
 	return ret;
 }
 
+static const struct mm_walk_ops charge_walk_ops = {
+	.pmd_entry	= mem_cgroup_move_charge_pte_range,
+};
+
 static void mem_cgroup_move_charge(void)
 {
-	struct mm_walk mem_cgroup_move_charge_walk = {
-		.pmd_entry = mem_cgroup_move_charge_pte_range,
-		.mm = mc.mm,
-	};
-
 	lru_add_drain_all();
 	/*
 	 * Signal lock_page_memcg() to take the memcg's move_lock
@@ -5309,7 +5978,8 @@
 	 * When we have consumed all precharges and failed in doing
 	 * additional charge, the page walk just aborts.
 	 */
-	walk_page_range(0, mc.mm->highest_vm_end, &mem_cgroup_move_charge_walk);
+	walk_page_range(mc.mm, 0, mc.mm->highest_vm_end, &charge_walk_ops,
+			NULL);
 
 	up_read(&mc.mm->mmap_sem);
 	atomic_dec(&mc.from->moving_account);
@@ -5353,6 +6023,16 @@
 		root_mem_cgroup->use_hierarchy = false;
 }
 
+static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
+{
+	if (value == PAGE_COUNTER_MAX)
+		seq_puts(m, "max\n");
+	else
+		seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE);
+
+	return 0;
+}
+
 static u64 memory_current_read(struct cgroup_subsys_state *css,
 			       struct cftype *cft)
 {
@@ -5363,15 +6043,8 @@
 
 static int memory_min_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
-	unsigned long min = READ_ONCE(memcg->memory.min);
-
-	if (min == PAGE_COUNTER_MAX)
-		seq_puts(m, "max\n");
-	else
-		seq_printf(m, "%llu\n", (u64)min * PAGE_SIZE);
-
-	return 0;
+	return seq_puts_memcg_tunable(m,
+		READ_ONCE(mem_cgroup_from_seq(m)->memory.min));
 }
 
 static ssize_t memory_min_write(struct kernfs_open_file *of,
@@ -5393,15 +6066,8 @@
 
 static int memory_low_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
-	unsigned long low = READ_ONCE(memcg->memory.low);
-
-	if (low == PAGE_COUNTER_MAX)
-		seq_puts(m, "max\n");
-	else
-		seq_printf(m, "%llu\n", (u64)low * PAGE_SIZE);
-
-	return 0;
+	return seq_puts_memcg_tunable(m,
+		READ_ONCE(mem_cgroup_from_seq(m)->memory.low));
 }
 
 static ssize_t memory_low_write(struct kernfs_open_file *of,
@@ -5423,15 +6089,7 @@
 
 static int memory_high_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
-	unsigned long high = READ_ONCE(memcg->high);
-
-	if (high == PAGE_COUNTER_MAX)
-		seq_puts(m, "max\n");
-	else
-		seq_printf(m, "%llu\n", (u64)high * PAGE_SIZE);
-
-	return 0;
+	return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->high));
 }
 
 static ssize_t memory_high_write(struct kernfs_open_file *of,
@@ -5460,15 +6118,8 @@
 
 static int memory_max_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
-	unsigned long max = READ_ONCE(memcg->memory.max);
-
-	if (max == PAGE_COUNTER_MAX)
-		seq_puts(m, "max\n");
-	else
-		seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
-
-	return 0;
+	return seq_puts_memcg_tunable(m,
+		READ_ONCE(mem_cgroup_from_seq(m)->memory.max));
 }
 
 static ssize_t memory_max_write(struct kernfs_open_file *of,
@@ -5520,104 +6171,48 @@
 	return nbytes;
 }
 
+static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
+{
+	seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW]));
+	seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH]));
+	seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX]));
+	seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
+	seq_printf(m, "oom_kill %lu\n",
+		   atomic_long_read(&events[MEMCG_OOM_KILL]));
+}
+
 static int memory_events_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
 
-	seq_printf(m, "low %lu\n",
-		   atomic_long_read(&memcg->memory_events[MEMCG_LOW]));
-	seq_printf(m, "high %lu\n",
-		   atomic_long_read(&memcg->memory_events[MEMCG_HIGH]));
-	seq_printf(m, "max %lu\n",
-		   atomic_long_read(&memcg->memory_events[MEMCG_MAX]));
-	seq_printf(m, "oom %lu\n",
-		   atomic_long_read(&memcg->memory_events[MEMCG_OOM]));
-	seq_printf(m, "oom_kill %lu\n",
-		   atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
+	__memory_events_show(m, memcg->memory_events);
+	return 0;
+}
 
+static int memory_events_local_show(struct seq_file *m, void *v)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+	__memory_events_show(m, memcg->memory_events_local);
 	return 0;
 }
 
 static int memory_stat_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
-	struct accumulated_stats acc;
-	int i;
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+	char *buf;
 
-	/*
-	 * Provide statistics on the state of the memory subsystem as
-	 * well as cumulative event counters that show past behavior.
-	 *
-	 * This list is ordered following a combination of these gradients:
-	 * 1) generic big picture -> specifics and details
-	 * 2) reflecting userspace activity -> reflecting kernel heuristics
-	 *
-	 * Current memory state:
-	 */
-
-	memset(&acc, 0, sizeof(acc));
-	acc.stats_size = MEMCG_NR_STAT;
-	acc.events_size = NR_VM_EVENT_ITEMS;
-	accumulate_memcg_tree(memcg, &acc);
-
-	seq_printf(m, "anon %llu\n",
-		   (u64)acc.stat[MEMCG_RSS] * PAGE_SIZE);
-	seq_printf(m, "file %llu\n",
-		   (u64)acc.stat[MEMCG_CACHE] * PAGE_SIZE);
-	seq_printf(m, "kernel_stack %llu\n",
-		   (u64)acc.stat[MEMCG_KERNEL_STACK_KB] * 1024);
-	seq_printf(m, "slab %llu\n",
-		   (u64)(acc.stat[NR_SLAB_RECLAIMABLE] +
-			 acc.stat[NR_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);
-	seq_printf(m, "sock %llu\n",
-		   (u64)acc.stat[MEMCG_SOCK] * PAGE_SIZE);
-
-	seq_printf(m, "shmem %llu\n",
-		   (u64)acc.stat[NR_SHMEM] * PAGE_SIZE);
-	seq_printf(m, "file_mapped %llu\n",
-		   (u64)acc.stat[NR_FILE_MAPPED] * PAGE_SIZE);
-	seq_printf(m, "file_dirty %llu\n",
-		   (u64)acc.stat[NR_FILE_DIRTY] * PAGE_SIZE);
-	seq_printf(m, "file_writeback %llu\n",
-		   (u64)acc.stat[NR_WRITEBACK] * PAGE_SIZE);
-
-	for (i = 0; i < NR_LRU_LISTS; i++)
-		seq_printf(m, "%s %llu\n", mem_cgroup_lru_names[i],
-			   (u64)acc.lru_pages[i] * PAGE_SIZE);
-
-	seq_printf(m, "slab_reclaimable %llu\n",
-		   (u64)acc.stat[NR_SLAB_RECLAIMABLE] * PAGE_SIZE);
-	seq_printf(m, "slab_unreclaimable %llu\n",
-		   (u64)acc.stat[NR_SLAB_UNRECLAIMABLE] * PAGE_SIZE);
-
-	/* Accumulated memory events */
-
-	seq_printf(m, "pgfault %lu\n", acc.events[PGFAULT]);
-	seq_printf(m, "pgmajfault %lu\n", acc.events[PGMAJFAULT]);
-
-	seq_printf(m, "pgrefill %lu\n", acc.events[PGREFILL]);
-	seq_printf(m, "pgscan %lu\n", acc.events[PGSCAN_KSWAPD] +
-		   acc.events[PGSCAN_DIRECT]);
-	seq_printf(m, "pgsteal %lu\n", acc.events[PGSTEAL_KSWAPD] +
-		   acc.events[PGSTEAL_DIRECT]);
-	seq_printf(m, "pgactivate %lu\n", acc.events[PGACTIVATE]);
-	seq_printf(m, "pgdeactivate %lu\n", acc.events[PGDEACTIVATE]);
-	seq_printf(m, "pglazyfree %lu\n", acc.events[PGLAZYFREE]);
-	seq_printf(m, "pglazyfreed %lu\n", acc.events[PGLAZYFREED]);
-
-	seq_printf(m, "workingset_refault %lu\n",
-		   acc.stat[WORKINGSET_REFAULT]);
-	seq_printf(m, "workingset_activate %lu\n",
-		   acc.stat[WORKINGSET_ACTIVATE]);
-	seq_printf(m, "workingset_nodereclaim %lu\n",
-		   acc.stat[WORKINGSET_NODERECLAIM]);
-
+	buf = memory_stat_format(memcg);
+	if (!buf)
+		return -ENOMEM;
+	seq_puts(m, buf);
+	kfree(buf);
 	return 0;
 }
 
 static int memory_oom_group_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
 
 	seq_printf(m, "%d\n", memcg->oom_group);
 
@@ -5683,6 +6278,12 @@
 		.seq_show = memory_events_show,
 	},
 	{
+		.name = "events.local",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.file_offset = offsetof(struct mem_cgroup, events_local_file),
+		.seq_show = memory_events_local_show,
+	},
+	{
 		.name = "stat",
 		.flags = CFTYPE_NOT_ON_ROOT,
 		.seq_show = memory_stat_show,
@@ -5746,7 +6347,7 @@
  *
  *             | memory.current, if memory.current < memory.low
  * low_usage = |
-	       | 0, otherwise.
+ *	       | 0, otherwise.
  *
  *
  * Such definition of the effective memory.low provides the expected
@@ -6045,7 +6646,7 @@
 	__mod_memcg_state(ug->memcg, MEMCG_RSS_HUGE, -ug->nr_huge);
 	__mod_memcg_state(ug->memcg, NR_SHMEM, -ug->nr_shmem);
 	__count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
-	__this_cpu_add(ug->memcg->stat_cpu->nr_page_events, nr_pages);
+	__this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, nr_pages);
 	memcg_check_events(ug->memcg, ug->dummy_page);
 	local_irq_restore(flags);
 
@@ -6080,7 +6681,7 @@
 		unsigned int nr_pages = 1;
 
 		if (PageTransHuge(page)) {
-			nr_pages <<= compound_order(page);
+			nr_pages = compound_nr(page);
 			ug->nr_huge += nr_pages;
 		}
 		if (PageAnon(page))
@@ -6092,7 +6693,7 @@
 		}
 		ug->pgpgout++;
 	} else {
-		ug->nr_kmem += 1 << compound_order(page);
+		ug->nr_kmem += compound_nr(page);
 		__ClearPageKmemcg(page);
 	}
 
@@ -6377,7 +6978,7 @@
 #ifdef CONFIG_MEMCG_SWAP
 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
 {
-	while (!atomic_inc_not_zero(&memcg->id.ref)) {
+	while (!refcount_inc_not_zero(&memcg->id.ref)) {
 		/*
 		 * The root cgroup cannot be destroyed, so it's refcount must
 		 * always be >= 1.
@@ -6600,15 +7201,8 @@
 
 static int swap_max_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
-	unsigned long max = READ_ONCE(memcg->swap.max);
-
-	if (max == PAGE_COUNTER_MAX)
-		seq_puts(m, "max\n");
-	else
-		seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
-
-	return 0;
+	return seq_puts_memcg_tunable(m,
+		READ_ONCE(mem_cgroup_from_seq(m)->swap.max));
 }
 
 static ssize_t swap_max_write(struct kernfs_open_file *of,
@@ -6630,7 +7224,7 @@
 
 static int swap_events_show(struct seq_file *m, void *v)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
 
 	seq_printf(m, "max %lu\n",
 		   atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));