Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 652f602..ae703ea 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /* memcontrol.h - Memory Controller
  *
  * Copyright IBM Corporation, 2007
@@ -5,16 +6,6 @@
  *
  * Copyright 2007 OpenVZ SWsoft Inc
  * Author: Pavel Emelianov <xemul@openvz.org>
- *
- * 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.
  */
 
 #ifndef _LINUX_MEMCONTROL_H
@@ -78,7 +69,7 @@
 
 struct mem_cgroup_id {
 	int id;
-	atomic_t ref;
+	refcount_t ref;
 };
 
 /*
@@ -94,8 +85,8 @@
 	MEM_CGROUP_NTARGETS,
 };
 
-struct mem_cgroup_stat_cpu {
-	long count[MEMCG_NR_STAT];
+struct memcg_vmstats_percpu {
+	long stat[MEMCG_NR_STAT];
 	unsigned long events[NR_VM_EVENT_ITEMS];
 	unsigned long nr_page_events;
 	unsigned long targets[MEM_CGROUP_NTARGETS];
@@ -126,6 +117,10 @@
 struct mem_cgroup_per_node {
 	struct lruvec		lruvec;
 
+	/* Legacy local VM stats */
+	struct lruvec_stat __percpu *lruvec_stat_local;
+
+	/* Subtree VM stats (batched updates) */
 	struct lruvec_stat __percpu *lruvec_stat_cpu;
 	atomic_long_t		lruvec_stat[NR_VM_NODE_STAT_ITEMS];
 
@@ -133,9 +128,8 @@
 
 	struct mem_cgroup_reclaim_iter	iter[DEF_PRIORITY + 1];
 
-#ifdef CONFIG_MEMCG_KMEM
 	struct memcg_shrinker_map __rcu	*shrinker_map;
-#endif
+
 	struct rb_node		tree_node;	/* RB tree node */
 	unsigned long		usage_in_excess;/* Set to the value by which */
 						/* the soft limit is exceeded*/
@@ -189,6 +183,23 @@
 #endif
 
 /*
+ * Remember four most recent foreign writebacks with dirty pages in this
+ * cgroup.  Inode sharing is expected to be uncommon and, even if we miss
+ * one in a given round, we're likely to catch it later if it keeps
+ * foreign-dirtying, so a fairly low count should be enough.
+ *
+ * See mem_cgroup_track_foreign_dirty_slowpath() for details.
+ */
+#define MEMCG_CGWB_FRN_CNT	4
+
+struct memcg_cgwb_frn {
+	u64 bdi_id;			/* bdi->id of the foreign inode */
+	int memcg_id;			/* memcg->css.id of foreign inode */
+	u64 at;				/* jiffies_64 at the time of dirtying */
+	struct wb_completion done;	/* tracks in-flight foreign writebacks */
+};
+
+/*
  * The memory controller data structure. The memory controller controls both
  * page cache and RSS per cgroup. We would eventually like to provide
  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
@@ -238,8 +249,9 @@
 	/* OOM-Killer disable */
 	int		oom_kill_disable;
 
-	/* memory.events */
+	/* memory.events and memory.events.local */
 	struct cgroup_file events_file;
+	struct cgroup_file events_local_file;
 
 	/* handle for "memory.swap.events" */
 	struct cgroup_file swap_events_file;
@@ -273,14 +285,20 @@
 	atomic_t		moving_account;
 	struct task_struct	*move_lock_task;
 
-	/* memory.stat */
-	struct mem_cgroup_stat_cpu __percpu *stat_cpu;
+	/* Legacy local VM stats and events */
+	struct memcg_vmstats_percpu __percpu *vmstats_local;
+
+	/* Subtree VM stats and events (batched updates) */
+	struct memcg_vmstats_percpu __percpu *vmstats_percpu;
 
 	MEMCG_PADDING(_pad2_);
 
-	atomic_long_t		stat[MEMCG_NR_STAT];
-	atomic_long_t		events[NR_VM_EVENT_ITEMS];
-	atomic_long_t memory_events[MEMCG_NR_MEMORY_EVENTS];
+	atomic_long_t		vmstats[MEMCG_NR_STAT];
+	atomic_long_t		vmevents[NR_VM_EVENT_ITEMS];
+
+	/* memory.events */
+	atomic_long_t		memory_events[MEMCG_NR_MEMORY_EVENTS];
+	atomic_long_t		memory_events_local[MEMCG_NR_MEMORY_EVENTS];
 
 	unsigned long		socket_pressure;
 
@@ -305,12 +323,17 @@
 #ifdef CONFIG_CGROUP_WRITEBACK
 	struct list_head cgwb_list;
 	struct wb_domain cgwb_domain;
+	struct memcg_cgwb_frn cgwb_frn[MEMCG_CGWB_FRN_CNT];
 #endif
 
 	/* List of events which userspace want to receive */
 	struct list_head event_list;
 	spinlock_t event_list_lock;
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	struct deferred_split deferred_split_queue;
+#endif
+
 	struct mem_cgroup_per_node *nodeinfo[0];
 	/* WARNING: nodeinfo must be the last member here */
 };
@@ -333,6 +356,19 @@
 	return !cgroup_subsys_enabled(memory_cgrp_subsys);
 }
 
+static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg,
+						  bool in_low_reclaim)
+{
+	if (mem_cgroup_disabled())
+		return 0;
+
+	if (in_low_reclaim)
+		return READ_ONCE(memcg->memory.emin);
+
+	return max(READ_ONCE(memcg->memory.emin),
+		   READ_ONCE(memcg->memory.elow));
+}
+
 enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
 						struct mem_cgroup *memcg);
 
@@ -392,7 +428,6 @@
 
 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
 
-bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 
 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
@@ -429,6 +464,11 @@
 }
 struct mem_cgroup *mem_cgroup_from_id(unsigned short id);
 
+static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
+{
+	return mem_cgroup_from_css(seq_css(m));
+}
+
 static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
 {
 	struct mem_cgroup_per_node *mz;
@@ -496,22 +536,6 @@
 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 		int zid, int nr_pages);
 
-unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
-					   int nid, unsigned int lru_mask);
-
-static inline
-unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
-{
-	struct mem_cgroup_per_node *mz;
-	unsigned long nr_pages = 0;
-	int zid;
-
-	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
-	for (zid = 0; zid < MAX_NR_ZONES; zid++)
-		nr_pages += mz->lru_zone_size[zid][lru];
-	return nr_pages;
-}
-
 static inline
 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
 		enum lru_list lru, int zone_idx)
@@ -526,9 +550,13 @@
 
 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg);
 
-void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
+unsigned long mem_cgroup_size(struct mem_cgroup *memcg);
+
+void mem_cgroup_print_oom_context(struct mem_cgroup *memcg,
 				struct task_struct *p);
 
+void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg);
+
 static inline void mem_cgroup_enter_user_fault(void)
 {
 	WARN_ON(current->in_user_fault);
@@ -559,11 +587,13 @@
 void __unlock_page_memcg(struct mem_cgroup *memcg);
 void unlock_page_memcg(struct page *page);
 
-/* idx can be of type enum memcg_stat_item or node_stat_item */
-static inline unsigned long memcg_page_state(struct mem_cgroup *memcg,
-					     int idx)
+/*
+ * idx can be of type enum memcg_stat_item or node_stat_item.
+ * Keep in sync with memcg_exact_page_state().
+ */
+static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
 {
-	long x = atomic_long_read(&memcg->stat[idx]);
+	long x = atomic_long_read(&memcg->vmstats[idx]);
 #ifdef CONFIG_SMP
 	if (x < 0)
 		x = 0;
@@ -571,23 +601,27 @@
 	return x;
 }
 
-/* idx can be of type enum memcg_stat_item or node_stat_item */
-static inline void __mod_memcg_state(struct mem_cgroup *memcg,
-				     int idx, int val)
+/*
+ * idx can be of type enum memcg_stat_item or node_stat_item.
+ * Keep in sync with memcg_exact_page_state().
+ */
+static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
+						   int idx)
 {
-	long x;
+	long x = 0;
+	int cpu;
 
-	if (mem_cgroup_disabled())
-		return;
-
-	x = val + __this_cpu_read(memcg->stat_cpu->count[idx]);
-	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
-		atomic_long_add(x, &memcg->stat[idx]);
+	for_each_possible_cpu(cpu)
+		x += per_cpu(memcg->vmstats_local->stat[idx], cpu);
+#ifdef CONFIG_SMP
+	if (x < 0)
 		x = 0;
-	}
-	__this_cpu_write(memcg->stat_cpu->count[idx], x);
+#endif
+	return x;
 }
 
+void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);
+
 /* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void mod_memcg_state(struct mem_cgroup *memcg,
 				   int idx, int val)
@@ -648,32 +682,30 @@
 	return x;
 }
 
-static inline void __mod_lruvec_state(struct lruvec *lruvec,
-				      enum node_stat_item idx, int val)
+static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
+						    enum node_stat_item idx)
 {
 	struct mem_cgroup_per_node *pn;
-	long x;
-
-	/* Update node */
-	__mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
+	long x = 0;
+	int cpu;
 
 	if (mem_cgroup_disabled())
-		return;
+		return node_page_state(lruvec_pgdat(lruvec), idx);
 
 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
-
-	/* Update memcg */
-	__mod_memcg_state(pn->memcg, idx, val);
-
-	/* Update lruvec */
-	x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]);
-	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
-		atomic_long_add(x, &pn->lruvec_stat[idx]);
+	for_each_possible_cpu(cpu)
+		x += per_cpu(pn->lruvec_stat_local->count[idx], cpu);
+#ifdef CONFIG_SMP
+	if (x < 0)
 		x = 0;
-	}
-	__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
+#endif
+	return x;
 }
 
+void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+			int val);
+void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val);
+
 static inline void mod_lruvec_state(struct lruvec *lruvec,
 				    enum node_stat_item idx, int val)
 {
@@ -714,22 +746,8 @@
 						gfp_t gfp_mask,
 						unsigned long *total_scanned);
 
-static inline 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->stat_cpu->events[idx]);
-	if (unlikely(x > MEMCG_CHARGE_BATCH)) {
-		atomic_long_add(x, &memcg->events[idx]);
-		x = 0;
-	}
-	__this_cpu_write(memcg->stat_cpu->events[idx], x);
-}
+void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
+			  unsigned long count);
 
 static inline void count_memcg_events(struct mem_cgroup *memcg,
 				      enum vm_event_item idx,
@@ -767,8 +785,17 @@
 static inline void memcg_memory_event(struct mem_cgroup *memcg,
 				      enum memcg_memory_event event)
 {
-	atomic_long_inc(&memcg->memory_events[event]);
-	cgroup_file_notify(&memcg->events_file);
+	atomic_long_inc(&memcg->memory_events_local[event]);
+	cgroup_file_notify(&memcg->events_local_file);
+
+	do {
+		atomic_long_inc(&memcg->memory_events[event]);
+		cgroup_file_notify(&memcg->events_file);
+
+		if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
+			break;
+	} while ((memcg = parent_mem_cgroup(memcg)) &&
+		 !mem_cgroup_is_root(memcg));
 }
 
 static inline void memcg_memory_event_mm(struct mm_struct *mm,
@@ -817,6 +844,12 @@
 {
 }
 
+static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg,
+						  bool in_low_reclaim)
+{
+	return 0;
+}
+
 static inline enum mem_cgroup_protection mem_cgroup_protected(
 	struct mem_cgroup *root, struct mem_cgroup *memcg)
 {
@@ -884,12 +917,6 @@
 	return true;
 }
 
-static inline bool task_in_mem_cgroup(struct task_struct *task,
-				      const struct mem_cgroup *memcg)
-{
-	return true;
-}
-
 static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
 {
 	return NULL;
@@ -935,6 +962,11 @@
 	return NULL;
 }
 
+static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
+{
+	return NULL;
+}
+
 static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
 {
 	return NULL;
@@ -945,11 +977,6 @@
 	return true;
 }
 
-static inline unsigned long
-mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
-{
-	return 0;
-}
 static inline
 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
 		enum lru_list lru, int zone_idx)
@@ -957,20 +984,23 @@
 	return 0;
 }
 
-static inline unsigned long
-mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
-			     int nid, unsigned int lru_mask)
-{
-	return 0;
-}
-
 static inline unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
 {
 	return 0;
 }
 
+static inline unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
+{
+	return 0;
+}
+
 static inline void
-mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
+mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
+{
+}
+
+static inline void
+mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
 {
 }
 
@@ -1019,8 +1049,13 @@
 {
 }
 
-static inline unsigned long memcg_page_state(struct mem_cgroup *memcg,
-					     int idx)
+static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
+{
+	return 0;
+}
+
+static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
+						   int idx)
 {
 	return 0;
 }
@@ -1055,6 +1090,12 @@
 	return node_page_state(lruvec_pgdat(lruvec), idx);
 }
 
+static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
+						    enum node_stat_item idx)
+{
+	return node_page_state(lruvec_pgdat(lruvec), idx);
+}
+
 static inline void __mod_lruvec_state(struct lruvec *lruvec,
 				      enum node_stat_item idx, int val)
 {
@@ -1079,6 +1120,14 @@
 	mod_node_page_state(page_pgdat(page), idx, val);
 }
 
+static inline void __mod_lruvec_slab_state(void *p, enum node_stat_item idx,
+					   int val)
+{
+	struct page *page = virt_to_head_page(p);
+
+	__mod_node_page_state(page_pgdat(page), idx, val);
+}
+
 static inline
 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 					    gfp_t gfp_mask,
@@ -1097,6 +1146,12 @@
 {
 }
 
+static inline void __count_memcg_events(struct mem_cgroup *memcg,
+					enum vm_event_item idx,
+					unsigned long count)
+{
+}
+
 static inline void count_memcg_page_event(struct page *page,
 					  int idx)
 {
@@ -1160,6 +1215,16 @@
 	__mod_lruvec_page_state(page, idx, -1);
 }
 
+static inline void __inc_lruvec_slab_state(void *p, enum node_stat_item idx)
+{
+	__mod_lruvec_slab_state(p, idx, 1);
+}
+
+static inline void __dec_lruvec_slab_state(void *p, enum node_stat_item idx)
+{
+	__mod_lruvec_slab_state(p, idx, -1);
+}
+
 /* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void inc_memcg_state(struct mem_cgroup *memcg,
 				   int idx)
@@ -1219,6 +1284,21 @@
 			 unsigned long *pheadroom, unsigned long *pdirty,
 			 unsigned long *pwriteback);
 
+void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
+					     struct bdi_writeback *wb);
+
+static inline void mem_cgroup_track_foreign_dirty(struct page *page,
+						  struct bdi_writeback *wb)
+{
+	if (mem_cgroup_disabled())
+		return;
+
+	if (unlikely(&page->mem_cgroup->css != wb->memcg_css))
+		mem_cgroup_track_foreign_dirty_slowpath(page, wb);
+}
+
+void mem_cgroup_flush_foreign(struct bdi_writeback *wb);
+
 #else	/* CONFIG_CGROUP_WRITEBACK */
 
 static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
@@ -1234,6 +1314,15 @@
 {
 }
 
+static inline void mem_cgroup_track_foreign_dirty(struct page *page,
+						  struct bdi_writeback *wb)
+{
+}
+
+static inline void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
+{
+}
+
 #endif	/* CONFIG_CGROUP_WRITEBACK */
 
 struct sock;
@@ -1254,6 +1343,11 @@
 	} while ((memcg = parent_mem_cgroup(memcg)));
 	return false;
 }
+
+extern int memcg_expand_shrinker_maps(int new_id);
+
+extern void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
+				   int nid, int shrinker_id);
 #else
 #define mem_cgroup_sockets_enabled 0
 static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
@@ -1262,16 +1356,24 @@
 {
 	return false;
 }
+
+static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
+					  int nid, int shrinker_id)
+{
+}
 #endif
 
 struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
 void memcg_kmem_put_cache(struct kmem_cache *cachep);
-int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
-			    struct mem_cgroup *memcg);
-int memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
-void memcg_kmem_uncharge(struct page *page, int order);
 
 #ifdef CONFIG_MEMCG_KMEM
+int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
+void __memcg_kmem_uncharge(struct page *page, int order);
+int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
+			      struct mem_cgroup *memcg);
+void __memcg_kmem_uncharge_memcg(struct mem_cgroup *memcg,
+				 unsigned int nr_pages);
+
 extern struct static_key_false memcg_kmem_enabled_key;
 extern struct workqueue_struct *memcg_kmem_cache_wq;
 
@@ -1292,6 +1394,34 @@
 	return static_branch_unlikely(&memcg_kmem_enabled_key);
 }
 
+static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
+{
+	if (memcg_kmem_enabled())
+		return __memcg_kmem_charge(page, gfp, order);
+	return 0;
+}
+
+static inline void memcg_kmem_uncharge(struct page *page, int order)
+{
+	if (memcg_kmem_enabled())
+		__memcg_kmem_uncharge(page, order);
+}
+
+static inline int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp,
+					  int order, struct mem_cgroup *memcg)
+{
+	if (memcg_kmem_enabled())
+		return __memcg_kmem_charge_memcg(page, gfp, order, memcg);
+	return 0;
+}
+
+static inline void memcg_kmem_uncharge_memcg(struct page *page, int order,
+					     struct mem_cgroup *memcg)
+{
+	if (memcg_kmem_enabled())
+		__memcg_kmem_uncharge_memcg(memcg, 1 << order);
+}
+
 /*
  * helper for accessing a memcg's index. It will be used as an index in the
  * child cache array in kmem_cache, and also to derive its name. This function
@@ -1302,11 +1432,26 @@
 	return memcg ? memcg->kmemcg_id : -1;
 }
 
-extern int memcg_expand_shrinker_maps(int new_id);
-
-extern void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
-				   int nid, int shrinker_id);
 #else
+
+static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
+{
+	return 0;
+}
+
+static inline void memcg_kmem_uncharge(struct page *page, int order)
+{
+}
+
+static inline int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
+{
+	return 0;
+}
+
+static inline void __memcg_kmem_uncharge(struct page *page, int order)
+{
+}
+
 #define for_each_memcg_cache_index(_idx)	\
 	for (; NULL; )
 
@@ -1328,8 +1473,6 @@
 {
 }
 
-static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
-					  int nid, int shrinker_id) { }
 #endif /* CONFIG_MEMCG_KMEM */
 
 #endif /* _LINUX_MEMCONTROL_H */