From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/mm/vmscan.c | 2027 +++++++++++++++++++++++++++++++++--------------------------
 1 files changed, 1,133 insertions(+), 894 deletions(-)

diff --git a/kernel/mm/vmscan.c b/kernel/mm/vmscan.c
index 17de2f3..f94f52e 100644
--- a/kernel/mm/vmscan.c
+++ b/kernel/mm/vmscan.c
@@ -63,6 +63,12 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/vmscan.h>
 
+#undef CREATE_TRACE_POINTS
+#include <trace/hooks/vmscan.h>
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(mm_vmscan_direct_reclaim_begin);
+EXPORT_TRACEPOINT_SYMBOL_GPL(mm_vmscan_direct_reclaim_end);
+
 struct scan_control {
 	/* How many pages shrink_list() should reclaim */
 	unsigned long nr_to_reclaim;
@@ -79,6 +85,19 @@
 	 */
 	struct mem_cgroup *target_mem_cgroup;
 
+	/*
+	 * Scan pressure balancing between anon and file LRUs
+	 */
+	unsigned long	anon_cost;
+	unsigned long	file_cost;
+
+	/* Can active pages be deactivated as part of reclaim? */
+#define DEACTIVATE_ANON 1
+#define DEACTIVATE_FILE 2
+	unsigned int may_deactivate:2;
+	unsigned int force_deactivate:1;
+	unsigned int skipped_deactivate:1;
+
 	/* Writepage batching in laptop mode; RECLAIM_WRITE */
 	unsigned int may_writepage:1;
 
@@ -89,9 +108,12 @@
 	unsigned int may_swap:1;
 
 	/*
-	 * Cgroups are not reclaimed below their configured memory.low,
-	 * unless we threaten to OOM. If any cgroups are skipped due to
-	 * memory.low and nothing was reclaimed, go back for memory.low.
+	 * Cgroup memory below memory.low is protected as long as we
+	 * don't threaten to OOM. If any cgroup is reclaimed at
+	 * reduced force or passed over entirely due to its memory.low
+	 * setting (memcg_low_skipped), and nothing is reclaimed as a
+	 * result, then go back for one more cycle that reclaims the protected
+	 * memory (memcg_low_reclaim) to avert OOM.
 	 */
 	unsigned int memcg_low_reclaim:1;
 	unsigned int memcg_low_skipped:1;
@@ -100,6 +122,12 @@
 
 	/* One of the zones is ready for compaction */
 	unsigned int compaction_ready:1;
+
+	/* There is easily reclaimable cold cache in the current node */
+	unsigned int cache_trim_mode:1;
+
+	/* The file pages on the current node are dangerously low */
+	unsigned int file_is_tiny:1;
 
 	/* Allocation order */
 	s8 order;
@@ -128,21 +156,10 @@
 		unsigned int file_taken;
 		unsigned int taken;
 	} nr;
-};
 
-#ifdef ARCH_HAS_PREFETCH
-#define prefetch_prev_lru_page(_page, _base, _field)			\
-	do {								\
-		if ((_page)->lru.prev != _base) {			\
-			struct page *prev;				\
-									\
-			prev = lru_to_page(&(_page->lru));		\
-			prefetch(&prev->_field);			\
-		}							\
-	} while (0)
-#else
-#define prefetch_prev_lru_page(_page, _base, _field) do { } while (0)
-#endif
+	/* for recording the reclaimed slab by now */
+	struct reclaim_state reclaim_state;
+};
 
 #ifdef ARCH_HAS_PREFETCHW
 #define prefetchw_prev_lru_page(_page, _base, _field)			\
@@ -159,20 +176,43 @@
 #endif
 
 /*
- * From 0 .. 100.  Higher means more swappy.
+ * From 0 .. 200.  Higher means more swappy.
  */
 int vm_swappiness = 60;
-/*
- * The total number of pages which are beyond the high watermark within all
- * zones.
- */
-unsigned long vm_total_pages;
+
+#define DEF_KSWAPD_THREADS_PER_NODE 1
+static int kswapd_threads = DEF_KSWAPD_THREADS_PER_NODE;
+static int __init kswapd_per_node_setup(char *str)
+{
+	int tmp;
+
+	if (kstrtoint(str, 0, &tmp) < 0)
+		return 0;
+
+	if (tmp > MAX_KSWAPD_THREADS || tmp <= 0)
+		return 0;
+
+	kswapd_threads = tmp;
+	return 1;
+}
+__setup("kswapd_per_node=", kswapd_per_node_setup);
+
+static void set_task_reclaim_state(struct task_struct *task,
+				   struct reclaim_state *rs)
+{
+	/* Check for an overwrite */
+	WARN_ON_ONCE(rs && task->reclaim_state);
+
+	/* Check for the nulling of an already-nulled member */
+	WARN_ON_ONCE(!rs && !task->reclaim_state);
+
+	task->reclaim_state = rs;
+}
 
 static LIST_HEAD(shrinker_list);
 static DECLARE_RWSEM(shrinker_rwsem);
 
-#ifdef CONFIG_MEMCG_KMEM
-
+#ifdef CONFIG_MEMCG
 /*
  * We allow subsystems to populate their shrinker-related
  * LRU lists before register_shrinker_prepared() is called
@@ -224,25 +264,14 @@
 	idr_remove(&shrinker_idr, id);
 	up_write(&shrinker_rwsem);
 }
-#else /* CONFIG_MEMCG_KMEM */
-static int prealloc_memcg_shrinker(struct shrinker *shrinker)
-{
-	return 0;
-}
 
-static void unregister_memcg_shrinker(struct shrinker *shrinker)
+static bool cgroup_reclaim(struct scan_control *sc)
 {
-}
-#endif /* CONFIG_MEMCG_KMEM */
-
-#ifdef CONFIG_MEMCG
-static bool global_reclaim(struct scan_control *sc)
-{
-	return !sc->target_mem_cgroup;
+	return sc->target_mem_cgroup;
 }
 
 /**
- * sane_reclaim - is the usual dirty throttling mechanism operational?
+ * writeback_throttling_sane - is the usual dirty throttling mechanism available?
  * @sc: scan_control in question
  *
  * The normal page dirty throttling mechanism in balance_dirty_pages() is
@@ -254,11 +283,9 @@
  * This function tests whether the vmscan currently in progress can assume
  * that the normal dirty throttling mechanism is operational.
  */
-static bool sane_reclaim(struct scan_control *sc)
+static bool writeback_throttling_sane(struct scan_control *sc)
 {
-	struct mem_cgroup *memcg = sc->target_mem_cgroup;
-
-	if (!memcg)
+	if (!cgroup_reclaim(sc))
 		return true;
 #ifdef CONFIG_CGROUP_WRITEBACK
 	if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
@@ -266,50 +293,24 @@
 #endif
 	return false;
 }
-
-static void set_memcg_congestion(pg_data_t *pgdat,
-				struct mem_cgroup *memcg,
-				bool congested)
-{
-	struct mem_cgroup_per_node *mn;
-
-	if (!memcg)
-		return;
-
-	mn = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
-	WRITE_ONCE(mn->congested, congested);
-}
-
-static bool memcg_congested(pg_data_t *pgdat,
-			struct mem_cgroup *memcg)
-{
-	struct mem_cgroup_per_node *mn;
-
-	mn = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
-	return READ_ONCE(mn->congested);
-
-}
 #else
-static bool global_reclaim(struct scan_control *sc)
+static int prealloc_memcg_shrinker(struct shrinker *shrinker)
 {
-	return true;
+	return 0;
 }
 
-static bool sane_reclaim(struct scan_control *sc)
-{
-	return true;
-}
-
-static inline void set_memcg_congestion(struct pglist_data *pgdat,
-				struct mem_cgroup *memcg, bool congested)
+static void unregister_memcg_shrinker(struct shrinker *shrinker)
 {
 }
 
-static inline bool memcg_congested(struct pglist_data *pgdat,
-			struct mem_cgroup *memcg)
+static bool cgroup_reclaim(struct scan_control *sc)
 {
 	return false;
+}
 
+static bool writeback_throttling_sane(struct scan_control *sc)
+{
+	return true;
 }
 #endif
 
@@ -339,31 +340,21 @@
  */
 unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx)
 {
-	unsigned long lru_size;
+	unsigned long size = 0;
 	int zid;
 
-	if (!mem_cgroup_disabled())
-		lru_size = mem_cgroup_get_lru_size(lruvec, lru);
-	else
-		lru_size = node_page_state(lruvec_pgdat(lruvec), NR_LRU_BASE + lru);
-
-	for (zid = zone_idx + 1; zid < MAX_NR_ZONES; zid++) {
+	for (zid = 0; zid <= zone_idx && zid < MAX_NR_ZONES; zid++) {
 		struct zone *zone = &lruvec_pgdat(lruvec)->node_zones[zid];
-		unsigned long size;
 
 		if (!managed_zone(zone))
 			continue;
 
 		if (!mem_cgroup_disabled())
-			size = mem_cgroup_get_zone_lru_size(lruvec, lru, zid);
+			size += mem_cgroup_get_zone_lru_size(lruvec, lru, zid);
 		else
-			size = zone_page_state(&lruvec_pgdat(lruvec)->node_zones[zid],
-				       NR_ZONE_LRU_BASE + lru);
-		lru_size -= min(size, lru_size);
+			size += zone_page_state(zone, NR_ZONE_LRU_BASE + lru);
 	}
-
-	return lru_size;
-
+	return size;
 }
 
 /*
@@ -371,7 +362,7 @@
  */
 int prealloc_shrinker(struct shrinker *shrinker)
 {
-	size_t size = sizeof(*shrinker->nr_deferred);
+	unsigned int size = sizeof(*shrinker->nr_deferred);
 
 	if (shrinker->flags & SHRINKER_NUMA_AWARE)
 		size *= nr_node_ids;
@@ -409,7 +400,7 @@
 {
 	down_write(&shrinker_rwsem);
 	list_add_tail(&shrinker->list, &shrinker_list);
-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG
 	if (shrinker->flags & SHRINKER_MEMCG_AWARE)
 		idr_replace(&shrinker_idr, shrinker, shrinker->id);
 #endif
@@ -475,13 +466,22 @@
 	nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
 
 	total_scan = nr;
-	delta = freeable >> priority;
-	delta *= 4;
-	do_div(delta, shrinker->seeks);
+	if (shrinker->seeks) {
+		delta = freeable >> priority;
+		delta *= 4;
+		do_div(delta, shrinker->seeks);
+	} else {
+		/*
+		 * These objects don't require any IO to create. Trim
+		 * them aggressively under memory pressure to keep
+		 * them from causing refetches in the IO caches.
+		 */
+		delta = freeable / 2;
+	}
 
 	total_scan += delta;
 	if (total_scan < 0) {
-		pr_err("shrink_slab: %pF negative objects to delete nr=%ld\n",
+		pr_err("shrink_slab: %pS negative objects to delete nr=%ld\n",
 		       shrinker->scan_objects, total_scan);
 		total_scan = freeable;
 		next_deferred = nr;
@@ -567,7 +567,7 @@
 	return freed;
 }
 
-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG
 static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
 			struct mem_cgroup *memcg, int priority)
 {
@@ -575,7 +575,7 @@
 	unsigned long ret, freed = 0;
 	int i;
 
-	if (!memcg_kmem_enabled() || !mem_cgroup_online(memcg))
+	if (!mem_cgroup_online(memcg))
 		return 0;
 
 	if (!down_read_trylock(&shrinker_rwsem))
@@ -600,6 +600,11 @@
 				clear_bit(i, map->map);
 			continue;
 		}
+
+		/* Call non-slab shrinkers even though kmem is disabled */
+		if (!memcg_kmem_enabled() &&
+		    !(shrinker->flags & SHRINKER_NONSLAB))
+			continue;
 
 		ret = do_shrink_slab(&sc, shrinker, priority);
 		if (ret == SHRINK_EMPTY) {
@@ -637,13 +642,13 @@
 	up_read(&shrinker_rwsem);
 	return freed;
 }
-#else /* CONFIG_MEMCG_KMEM */
+#else /* CONFIG_MEMCG */
 static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
 			struct mem_cgroup *memcg, int priority)
 {
 	return 0;
 }
-#endif /* CONFIG_MEMCG_KMEM */
+#endif /* CONFIG_MEMCG */
 
 /**
  * shrink_slab - shrink slab caches
@@ -665,12 +670,17 @@
  *
  * Returns the number of reclaimed slab objects.
  */
-static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
+unsigned long shrink_slab(gfp_t gfp_mask, int nid,
 				 struct mem_cgroup *memcg,
 				 int priority)
 {
 	unsigned long ret, freed = 0;
 	struct shrinker *shrinker;
+	bool bypass = false;
+
+	trace_android_vh_shrink_slab_bypass(gfp_mask, nid, memcg, priority, &bypass);
+	if (bypass)
+		return 0;
 
 	/*
 	 * The root memcg might be allocated even though memcg is disabled
@@ -698,7 +708,7 @@
 		freed += ret;
 		/*
 		 * Bail out if someone want to register a new shrinker to
-		 * prevent the regsitration from being stalled for long periods
+		 * prevent the registration from being stalled for long periods
 		 * by parallel ongoing shrinking.
 		 */
 		if (rwsem_is_contended(&shrinker_rwsem)) {
@@ -712,6 +722,7 @@
 	cond_resched();
 	return freed;
 }
+EXPORT_SYMBOL_GPL(shrink_slab);
 
 void drop_slab_node(int nid)
 {
@@ -719,6 +730,9 @@
 
 	do {
 		struct mem_cgroup *memcg = NULL;
+
+		if (fatal_signal_pending(current))
+			return;
 
 		freed = 0;
 		memcg = mem_cgroup_iter(NULL, NULL, NULL);
@@ -740,15 +754,14 @@
 {
 	/*
 	 * A freeable page cache page is referenced only by the caller
-	 * that isolated the page, the page cache radix tree and
-	 * optional buffer heads at page->private.
+	 * that isolated the page, the page cache and optional buffer
+	 * heads at page->private.
 	 */
-	int radix_pins = PageTransHuge(page) && PageSwapCache(page) ?
-		HPAGE_PMD_NR : 1;
-	return page_count(page) - page_has_private(page) == 1 + radix_pins;
+	int page_cache_pins = thp_nr_pages(page);
+	return page_count(page) - page_has_private(page) == 1 + page_cache_pins;
 }
 
-static int may_write_to_inode(struct inode *inode, struct scan_control *sc)
+static int may_write_to_inode(struct inode *inode)
 {
 	if (current->flags & PF_SWAPWRITE)
 		return 1;
@@ -796,8 +809,7 @@
  * pageout is called by shrink_page_list() for each dirty page.
  * Calls ->writepage().
  */
-static pageout_t pageout(struct page *page, struct address_space *mapping,
-			 struct scan_control *sc)
+static pageout_t pageout(struct page *page, struct address_space *mapping)
 {
 	/*
 	 * If the page is dirty, only perform writeback if that write
@@ -833,7 +845,7 @@
 	}
 	if (mapping->a_ops->writepage == NULL)
 		return PAGE_ACTIVATE;
-	if (!may_write_to_inode(mapping->host, sc))
+	if (!may_write_to_inode(mapping->host))
 		return PAGE_KEEP;
 
 	if (clear_page_dirty_for_io(page)) {
@@ -872,10 +884,11 @@
  * gets returned with a refcount of 0.
  */
 static int __remove_mapping(struct address_space *mapping, struct page *page,
-			    bool reclaimed)
+			    bool reclaimed, struct mem_cgroup *target_memcg)
 {
 	unsigned long flags;
 	int refcount;
+	void *shadow = NULL;
 
 	BUG_ON(!PageLocked(page));
 	BUG_ON(mapping != page_mapping(page));
@@ -906,10 +919,7 @@
 	 * Note that if SetPageDirty is always performed via set_page_dirty,
 	 * and thus under the i_pages lock, then this ordering is not required.
 	 */
-	if (unlikely(PageTransHuge(page)) && PageSwapCache(page))
-		refcount = 1 + HPAGE_PMD_NR;
-	else
-		refcount = 2;
+	refcount = 1 + compound_nr(page);
 	if (!page_ref_freeze(page, refcount))
 		goto cannot_free;
 	/* note: atomic_cmpxchg in page_ref_freeze provides the smp_rmb */
@@ -921,12 +931,13 @@
 	if (PageSwapCache(page)) {
 		swp_entry_t swap = { .val = page_private(page) };
 		mem_cgroup_swapout(page, swap);
-		__delete_from_swap_cache(page);
+		if (reclaimed && !mapping_exiting(mapping))
+			shadow = workingset_eviction(page, target_memcg);
+		__delete_from_swap_cache(page, swap, shadow);
 		xa_unlock_irqrestore(&mapping->i_pages, flags);
 		put_swap_page(page, swap);
 	} else {
 		void (*freepage)(struct page *);
-		void *shadow = NULL;
 
 		freepage = mapping->a_ops->freepage;
 		/*
@@ -934,7 +945,7 @@
 		 * order to detect refaults, thus thrashing, later on.
 		 *
 		 * But don't store shadows in an address space that is
-		 * already exiting.  This is not just an optizimation,
+		 * already exiting.  This is not just an optimization,
 		 * inode reclaim needs to empty out the radix tree or
 		 * the nodes are lost.  Don't plant shadows behind its
 		 * back.
@@ -945,9 +956,9 @@
 		 * exceptional entries and shadow exceptional entries in the
 		 * same address_space.
 		 */
-		if (reclaimed && page_is_file_cache(page) &&
+		if (reclaimed && page_is_file_lru(page) &&
 		    !mapping_exiting(mapping) && !dax_mapping(mapping))
-			shadow = workingset_eviction(mapping, page);
+			shadow = workingset_eviction(page, target_memcg);
 		__delete_from_page_cache(page, shadow);
 		xa_unlock_irqrestore(&mapping->i_pages, flags);
 
@@ -970,7 +981,7 @@
  */
 int remove_mapping(struct address_space *mapping, struct page *page)
 {
-	if (__remove_mapping(mapping, page, false)) {
+	if (__remove_mapping(mapping, page, false, NULL)) {
 		/*
 		 * Unfreezing the refcount with 1 rather than 2 effectively
 		 * drops the pagecache ref for us without requiring another
@@ -1009,11 +1020,24 @@
 {
 	int referenced_ptes, referenced_page;
 	unsigned long vm_flags;
+	bool should_protect = false;
+	bool trylock_fail = false;
+	int ret = 0;
 
+	trace_android_vh_page_should_be_protected(page, &should_protect);
+	if (unlikely(should_protect))
+		return PAGEREF_ACTIVATE;
+
+	trace_android_vh_page_trylock_set(page);
+	trace_android_vh_check_page_look_around_ref(page, &ret);
+	if (ret)
+		return ret;
 	referenced_ptes = page_referenced(page, 1, sc->target_mem_cgroup,
 					  &vm_flags);
 	referenced_page = TestClearPageReferenced(page);
-
+	trace_android_vh_page_trylock_get_result(page, &trylock_fail);
+	if (trylock_fail)
+		return PAGEREF_KEEP;
 	/*
 	 * Mlock lost the isolation race with us.  Let try_to_unmap()
 	 * move the page to the unevictable list.
@@ -1021,9 +1045,11 @@
 	if (vm_flags & VM_LOCKED)
 		return PAGEREF_RECLAIM;
 
+	/* rmap lock contention: rotate */
+	if (referenced_ptes == -1)
+		return PAGEREF_KEEP;
+
 	if (referenced_ptes) {
-		if (PageSwapBacked(page))
-			return PAGEREF_ACTIVATE;
 		/*
 		 * All mapped pages start out with page table
 		 * references from the instantiating fault, so we need
@@ -1046,7 +1072,7 @@
 		/*
 		 * Activate file-backed executable pages after first usage.
 		 */
-		if (vm_flags & VM_EXEC)
+		if ((vm_flags & VM_EXEC) && !PageSwapBacked(page))
 			return PAGEREF_ACTIVATE;
 
 		return PAGEREF_KEEP;
@@ -1069,7 +1095,7 @@
 	 * Anonymous pages are not handled by flushers and must be written
 	 * from reclaim context. Do not stall reclaim based on them
 	 */
-	if (!page_is_file_cache(page) ||
+	if (!page_is_file_lru(page) ||
 	    (PageAnon(page) && !PageSwapBacked(page))) {
 		*dirty = false;
 		*writeback = false;
@@ -1092,33 +1118,27 @@
 /*
  * shrink_page_list() returns the number of reclaimed pages
  */
-static unsigned long shrink_page_list(struct list_head *page_list,
-				      struct pglist_data *pgdat,
-				      struct scan_control *sc,
-				      enum ttu_flags ttu_flags,
-				      struct reclaim_stat *stat,
-				      bool force_reclaim)
+static unsigned int shrink_page_list(struct list_head *page_list,
+				     struct pglist_data *pgdat,
+				     struct scan_control *sc,
+				     struct reclaim_stat *stat,
+				     bool ignore_references)
 {
 	LIST_HEAD(ret_pages);
 	LIST_HEAD(free_pages);
-	int pgactivate = 0;
-	unsigned nr_unqueued_dirty = 0;
-	unsigned nr_dirty = 0;
-	unsigned nr_congested = 0;
-	unsigned nr_reclaimed = 0;
-	unsigned nr_writeback = 0;
-	unsigned nr_immediate = 0;
-	unsigned nr_ref_keep = 0;
-	unsigned nr_unmap_fail = 0;
+	unsigned int nr_reclaimed = 0;
+	unsigned int pgactivate = 0;
+	bool page_trylock_result;
 
+	memset(stat, 0, sizeof(*stat));
 	cond_resched();
 
 	while (!list_empty(page_list)) {
 		struct address_space *mapping;
 		struct page *page;
-		int may_enter_fs;
-		enum page_references references = PAGEREF_RECLAIM_CLEAN;
-		bool dirty, writeback;
+		enum page_references references = PAGEREF_RECLAIM;
+		bool dirty, writeback, may_enter_fs;
+		unsigned int nr_pages;
 
 		cond_resched();
 
@@ -1130,18 +1150,16 @@
 
 		VM_BUG_ON_PAGE(PageActive(page), page);
 
-		sc->nr_scanned++;
+		nr_pages = compound_nr(page);
+
+		/* Account the number of base pages even though THP */
+		sc->nr_scanned += nr_pages;
 
 		if (unlikely(!page_evictable(page)))
 			goto activate_locked;
 
 		if (!sc->may_unmap && page_mapped(page))
 			goto keep_locked;
-
-		/* Double the slab pressure for mapped and swapcache pages */
-		if ((page_mapped(page) || PageSwapCache(page)) &&
-		    !(PageAnon(page) && !PageSwapBacked(page)))
-			sc->nr_scanned++;
 
 		may_enter_fs = (sc->gfp_mask & __GFP_FS) ||
 			(PageSwapCache(page) && (sc->gfp_mask & __GFP_IO));
@@ -1154,10 +1172,10 @@
 		 */
 		page_check_dirty_writeback(page, &dirty, &writeback);
 		if (dirty || writeback)
-			nr_dirty++;
+			stat->nr_dirty++;
 
 		if (dirty && !writeback)
-			nr_unqueued_dirty++;
+			stat->nr_unqueued_dirty++;
 
 		/*
 		 * Treat this page as congested if the underlying BDI is or if
@@ -1169,7 +1187,7 @@
 		if (((dirty || writeback) && mapping &&
 		     inode_write_congested(mapping->host)) ||
 		    (writeback && PageReclaim(page)))
-			nr_congested++;
+			stat->nr_congested++;
 
 		/*
 		 * If a page at the tail of the LRU is under writeback, there
@@ -1218,11 +1236,11 @@
 			if (current_is_kswapd() &&
 			    PageReclaim(page) &&
 			    test_bit(PGDAT_WRITEBACK, &pgdat->flags)) {
-				nr_immediate++;
+				stat->nr_immediate++;
 				goto activate_locked;
 
 			/* Case 2 above */
-			} else if (sane_reclaim(sc) ||
+			} else if (writeback_throttling_sane(sc) ||
 			    !PageReclaim(page) || !may_enter_fs) {
 				/*
 				 * This is slightly racy - end_page_writeback()
@@ -1236,7 +1254,7 @@
 				 * and it's also appropriate in global reclaim.
 				 */
 				SetPageReclaim(page);
-				nr_writeback++;
+				stat->nr_writeback++;
 				goto activate_locked;
 
 			/* Case 3 above */
@@ -1249,14 +1267,14 @@
 			}
 		}
 
-		if (!force_reclaim)
+		if (!ignore_references)
 			references = page_check_references(page, sc);
 
 		switch (references) {
 		case PAGEREF_ACTIVATE:
 			goto activate_locked;
 		case PAGEREF_KEEP:
-			nr_ref_keep++;
+			stat->nr_ref_keep += nr_pages;
 			goto keep_locked;
 		case PAGEREF_RECLAIM:
 		case PAGEREF_RECLAIM_CLEAN:
@@ -1271,6 +1289,8 @@
 		if (PageAnon(page) && PageSwapBacked(page)) {
 			if (!PageSwapCache(page)) {
 				if (!(sc->gfp_mask & __GFP_IO))
+					goto keep_locked;
+				if (page_maybe_dma_pinned(page))
 					goto keep_locked;
 				if (PageTransHuge(page)) {
 					/* cannot split THP, skip it */
@@ -1288,7 +1308,7 @@
 				}
 				if (!add_to_swap(page)) {
 					if (!PageTransHuge(page))
-						goto activate_locked;
+						goto activate_locked_split;
 					/* Fallback to swap normal pages */
 					if (split_huge_page_to_list(page,
 								    page_list))
@@ -1297,10 +1317,10 @@
 					count_vm_event(THP_SWPOUT_FALLBACK);
 #endif
 					if (!add_to_swap(page))
-						goto activate_locked;
+						goto activate_locked_split;
 				}
 
-				may_enter_fs = 1;
+				may_enter_fs = true;
 
 				/* Adding to swap updated mapping */
 				mapping = page_mapping(page);
@@ -1312,16 +1332,33 @@
 		}
 
 		/*
+		 * THP may get split above, need minus tail pages and update
+		 * nr_pages to avoid accounting tail pages twice.
+		 *
+		 * The tail pages that are added into swap cache successfully
+		 * reach here.
+		 */
+		if ((nr_pages > 1) && !PageTransHuge(page)) {
+			sc->nr_scanned -= (nr_pages - 1);
+			nr_pages = 1;
+		}
+
+		/*
 		 * The page is mapped into the page tables of one or more
 		 * processes. Try to unmap it here.
 		 */
 		if (page_mapped(page)) {
-			enum ttu_flags flags = ttu_flags | TTU_BATCH_FLUSH;
+			enum ttu_flags flags = TTU_BATCH_FLUSH;
+			bool was_swapbacked = PageSwapBacked(page);
 
 			if (unlikely(PageTransHuge(page)))
 				flags |= TTU_SPLIT_HUGE_PMD;
+			if (!ignore_references)
+				trace_android_vh_page_trylock_set(page);
 			if (!try_to_unmap(page, flags)) {
-				nr_unmap_fail++;
+				stat->nr_unmap_fail += nr_pages;
+				if (!was_swapbacked && PageSwapBacked(page))
+					stat->nr_lazyfree_fail += nr_pages;
 				goto activate_locked;
 			}
 		}
@@ -1337,7 +1374,7 @@
 			 * the rest of the LRU for clean pages and see
 			 * the same dirty pages again (PageReclaim).
 			 */
-			if (page_is_file_cache(page) &&
+			if (page_is_file_lru(page) &&
 			    (!current_is_kswapd() || !PageReclaim(page) ||
 			     !test_bit(PGDAT_DIRTY, &pgdat->flags))) {
 				/*
@@ -1365,12 +1402,14 @@
 			 * starts and then write it out here.
 			 */
 			try_to_unmap_flush_dirty();
-			switch (pageout(page, mapping, sc)) {
+			switch (pageout(page, mapping)) {
 			case PAGE_KEEP:
 				goto keep_locked;
 			case PAGE_ACTIVATE:
 				goto activate_locked;
 			case PAGE_SUCCESS:
+				stat->nr_pageout += thp_nr_pages(page);
+
 				if (PageWriteback(page))
 					goto keep;
 				if (PageDirty(page))
@@ -1426,6 +1465,7 @@
 					 * increment nr_reclaimed here (and
 					 * leave it off the LRU).
 					 */
+					trace_android_vh_page_trylock_clear(page);
 					nr_reclaimed++;
 					continue;
 				}
@@ -1443,30 +1483,38 @@
 
 			count_vm_event(PGLAZYFREED);
 			count_memcg_page_event(page, PGLAZYFREED);
-		} else if (!mapping || !__remove_mapping(mapping, page, true))
+		} else if (!mapping || !__remove_mapping(mapping, page, true,
+							 sc->target_mem_cgroup))
 			goto keep_locked;
-		/*
-		 * At this point, we have no other references and there is
-		 * no way to pick any more up (removed from LRU, removed
-		 * from pagecache). Can use non-atomic bitops now (and
-		 * we obviously don't have to worry about waking up a process
-		 * waiting on the page lock, because there are no references.
-		 */
-		__ClearPageLocked(page);
+
+		unlock_page(page);
 free_it:
-		nr_reclaimed++;
+		/*
+		 * THP may get swapped out in a whole, need account
+		 * all base pages.
+		 */
+		nr_reclaimed += nr_pages;
 
 		/*
 		 * Is there need to periodically free_page_list? It would
 		 * appear not as the counts should be low
 		 */
-		if (unlikely(PageTransHuge(page))) {
-			mem_cgroup_uncharge(page);
-			(*get_compound_page_dtor(page))(page);
-		} else
+		trace_android_vh_page_trylock_clear(page);
+		if (unlikely(PageTransHuge(page)))
+			destroy_compound_page(page);
+		else
 			list_add(&page->lru, &free_pages);
 		continue;
 
+activate_locked_split:
+		/*
+		 * The tail pages that are failed to add into swap cache
+		 * reach here.  Fixup nr_scanned and nr_pages.
+		 */
+		if (nr_pages > 1) {
+			sc->nr_scanned -= (nr_pages - 1);
+			nr_pages = 1;
+		}
 activate_locked:
 		/* Not a candidate for swapping, so reclaim swap space. */
 		if (PageSwapCache(page) && (mem_cgroup_swap_full(page) ||
@@ -1474,16 +1522,31 @@
 			try_to_free_swap(page);
 		VM_BUG_ON_PAGE(PageActive(page), page);
 		if (!PageMlocked(page)) {
+			int type = page_is_file_lru(page);
 			SetPageActive(page);
-			pgactivate++;
+			stat->nr_activate[type] += nr_pages;
 			count_memcg_page_event(page, PGACTIVATE);
 		}
 keep_locked:
+		/*
+		 * The page with trylock-bit will be added ret_pages and
+		 * handled in trace_android_vh_handle_failed_page_trylock.
+		 * In the progress[unlock_page, handled], the page carried
+		 * with trylock-bit will cause some error-issues in other
+		 * scene, so clear trylock-bit here.
+		 * trace_android_vh_page_trylock_get_result will clear
+		 * trylock-bit and return if page tyrlock failed in
+		 * reclaim-process. Here we just want to clear trylock-bit
+		 * so that ignore page_trylock_result.
+		 */
+		trace_android_vh_page_trylock_get_result(page, &page_trylock_result);
 		unlock_page(page);
 keep:
 		list_add(&page->lru, &ret_pages);
 		VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page);
 	}
+
+	pgactivate = stat->nr_activate[0] + stat->nr_activate[1];
 
 	mem_cgroup_uncharge_list(&free_pages);
 	try_to_unmap_flush();
@@ -1492,20 +1555,10 @@
 	list_splice(&ret_pages, page_list);
 	count_vm_events(PGACTIVATE, pgactivate);
 
-	if (stat) {
-		stat->nr_dirty = nr_dirty;
-		stat->nr_congested = nr_congested;
-		stat->nr_unqueued_dirty = nr_unqueued_dirty;
-		stat->nr_writeback = nr_writeback;
-		stat->nr_immediate = nr_immediate;
-		stat->nr_activate = pgactivate;
-		stat->nr_ref_keep = nr_ref_keep;
-		stat->nr_unmap_fail = nr_unmap_fail;
-	}
 	return nr_reclaimed;
 }
 
-unsigned long reclaim_clean_pages_from_list(struct zone *zone,
+unsigned int reclaim_clean_pages_from_list(struct zone *zone,
 					    struct list_head *page_list)
 {
 	struct scan_control sc = {
@@ -1513,23 +1566,35 @@
 		.priority = DEF_PRIORITY,
 		.may_unmap = 1,
 	};
-	unsigned long ret;
+	struct reclaim_stat stat;
+	unsigned int nr_reclaimed;
 	struct page *page, *next;
 	LIST_HEAD(clean_pages);
 
 	list_for_each_entry_safe(page, next, page_list, lru) {
-		if (page_is_file_cache(page) && !PageDirty(page) &&
+		if (page_is_file_lru(page) && !PageDirty(page) &&
 		    !__PageMovable(page) && !PageUnevictable(page)) {
 			ClearPageActive(page);
 			list_move(&page->lru, &clean_pages);
 		}
 	}
 
-	ret = shrink_page_list(&clean_pages, zone->zone_pgdat, &sc,
-			TTU_IGNORE_ACCESS, NULL, true);
+	nr_reclaimed = shrink_page_list(&clean_pages, zone->zone_pgdat, &sc,
+					&stat, true);
 	list_splice(&clean_pages, page_list);
-	mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, -ret);
-	return ret;
+	mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE,
+			    -(long)nr_reclaimed);
+	/*
+	 * Since lazyfree pages are isolated from file LRU from the beginning,
+	 * they will rotate back to anonymous LRU in the end if it failed to
+	 * discard so isolated count will be mismatched.
+	 * Compensate the isolated count for both LRU lists.
+	 */
+	mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON,
+			    stat.nr_lazyfree_fail);
+	mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE,
+			    -(long)stat.nr_lazyfree_fail);
+	return nr_reclaimed;
 }
 
 /*
@@ -1612,7 +1677,7 @@
 
 /*
  * Update LRU sizes after isolating pages. The LRU size updates must
- * be complete before mem_cgroup_update_lru_size due to a santity check.
+ * be complete before mem_cgroup_update_lru_size due to a sanity check.
  */
 static __always_inline void update_lru_sizes(struct lruvec *lruvec,
 			enum lru_list lru, unsigned long *nr_zone_taken)
@@ -1623,16 +1688,13 @@
 		if (!nr_zone_taken[zid])
 			continue;
 
-		__update_lru_size(lruvec, lru, zid, -nr_zone_taken[zid]);
-#ifdef CONFIG_MEMCG
-		mem_cgroup_update_lru_size(lruvec, lru, zid, -nr_zone_taken[zid]);
-#endif
+		update_lru_size(lruvec, lru, zid, -nr_zone_taken[zid]);
 	}
 
 }
 
-/*
- * zone_lru_lock is heavily contended.  Some of the functions that
+/**
+ * pgdat->lru_lock is heavily contended.  Some of the functions that
  * shrink the lists perform better by taking out a batch of pages
  * and working on them outside the LRU lock.
  *
@@ -1646,7 +1708,6 @@
  * @dst:	The temp list to put pages on to.
  * @nr_scanned:	The number of pages that were scanned.
  * @sc:		The scan_control struct for this reclaim session
- * @mode:	One of the LRU isolation modes
  * @lru:	LRU list id for isolating
  *
  * returns how many pages were moved onto *@dst.
@@ -1654,7 +1715,7 @@
 static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 		struct lruvec *lruvec, struct list_head *dst,
 		unsigned long *nr_scanned, struct scan_control *sc,
-		isolate_mode_t mode, enum lru_list lru)
+		enum lru_list lru)
 {
 	struct list_head *src = &lruvec->lists[lru];
 	unsigned long nr_taken = 0;
@@ -1663,11 +1724,11 @@
 	unsigned long skipped = 0;
 	unsigned long scan, total_scan, nr_pages;
 	LIST_HEAD(pages_skipped);
+	isolate_mode_t mode = (sc->may_unmap ? 0 : ISOLATE_UNMAPPED);
 
+	total_scan = 0;
 	scan = 0;
-	for (total_scan = 0;
-	     scan < nr_to_scan && nr_taken < nr_to_scan && !list_empty(src);
-	     total_scan++) {
+	while (scan < nr_to_scan && !list_empty(src)) {
 		struct page *page;
 
 		page = lru_to_page(src);
@@ -1675,9 +1736,12 @@
 
 		VM_BUG_ON_PAGE(!PageLRU(page), page);
 
+		nr_pages = compound_nr(page);
+		total_scan += nr_pages;
+
 		if (page_zonenum(page) > sc->reclaim_idx) {
 			list_move(&page->lru, &pages_skipped);
-			nr_skipped[page_zonenum(page)]++;
+			nr_skipped[page_zonenum(page)] += nr_pages;
 			continue;
 		}
 
@@ -1686,13 +1750,17 @@
 		 * return with no isolated pages if the LRU mostly contains
 		 * ineligible pages.  This causes the VM to not reclaim any
 		 * pages, triggering a premature OOM.
+		 *
+		 * Account all tail pages of THP.  This would not cause
+		 * premature OOM since __isolate_lru_page() returns -EBUSY
+		 * only when the page is being freed somewhere else.
 		 */
-		scan++;
+		scan += nr_pages;
 		switch (__isolate_lru_page(page, mode)) {
 		case 0:
-			nr_pages = hpage_nr_pages(page);
 			nr_taken += nr_pages;
 			nr_zone_taken[page_zonenum(page)] += nr_pages;
+			trace_android_vh_del_page_from_lrulist(page, false, lru);
 			list_move(&page->lru, dst);
 			break;
 
@@ -1753,7 +1821,7 @@
  * Restrictions:
  *
  * (1) Must be called with an elevated refcount on the page. This is a
- *     fundamentnal difference from isolate_lru_pages (which is called
+ *     fundamental difference from isolate_lru_pages (which is called
  *     without a stable reference).
  * (2) the lru_lock must not be held.
  * (3) interrupts must be enabled.
@@ -1766,11 +1834,11 @@
 	WARN_RATELIMIT(PageTail(page), "trying to isolate tail page");
 
 	if (PageLRU(page)) {
-		struct zone *zone = page_zone(page);
+		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 
-		spin_lock_irq(zone_lru_lock(zone));
-		lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
+		spin_lock_irq(&pgdat->lru_lock);
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		if (PageLRU(page)) {
 			int lru = page_lru(page);
 			get_page(page);
@@ -1778,14 +1846,14 @@
 			del_page_from_lru_list(page, lruvec, lru);
 			ret = 0;
 		}
-		spin_unlock_irq(zone_lru_lock(zone));
+		spin_unlock_irq(&pgdat->lru_lock);
 	}
 	return ret;
 }
 
 /*
  * A direct reclaimer may isolate SWAP_CLUSTER_MAX pages from the LRU list and
- * then get resheduled. When there are massive number of tasks doing page
+ * then get rescheduled. When there are massive number of tasks doing page
  * allocation, such sleeping direct reclaimers may keep piling up on each CPU,
  * the LRU list will go small and be scanned faster than necessary, leading to
  * unnecessary swapping, thrashing and OOM.
@@ -1798,7 +1866,7 @@
 	if (current_is_kswapd())
 		return 0;
 
-	if (!sane_reclaim(sc))
+	if (!writeback_throttling_sane(sc))
 		return 0;
 
 	if (file) {
@@ -1820,40 +1888,55 @@
 	return isolated > inactive;
 }
 
-static noinline_for_stack void
-putback_inactive_pages(struct lruvec *lruvec, struct list_head *page_list)
+/*
+ * This moves pages from @list to corresponding LRU list.
+ *
+ * We move them the other way if the page is referenced by one or more
+ * processes, from rmap.
+ *
+ * If the pages are mostly unmapped, the processing is fast and it is
+ * appropriate to hold zone_lru_lock across the whole operation.  But if
+ * the pages are mapped, the processing is slow (page_referenced()) so we
+ * should drop zone_lru_lock around each page.  It's impossible to balance
+ * this, so instead we remove the pages from the LRU while processing them.
+ * It is safe to rely on PG_active against the non-LRU pages in here because
+ * nobody will play with that bit on a non-LRU page.
+ *
+ * The downside is that we have to touch page->_refcount against each page.
+ * But we had to alter page->flags anyway.
+ *
+ * Returns the number of pages moved to the given lruvec.
+ */
+
+static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
+						     struct list_head *list)
 {
-	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
+	int nr_pages, nr_moved = 0;
 	LIST_HEAD(pages_to_free);
+	struct page *page;
+	enum lru_list lru;
 
-	/*
-	 * Put back any unfreeable pages.
-	 */
-	while (!list_empty(page_list)) {
-		struct page *page = lru_to_page(page_list);
-		int lru;
-
+	while (!list_empty(list)) {
+		page = lru_to_page(list);
 		VM_BUG_ON_PAGE(PageLRU(page), page);
-		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
+			list_del(&page->lru);
 			spin_unlock_irq(&pgdat->lru_lock);
 			putback_lru_page(page);
 			spin_lock_irq(&pgdat->lru_lock);
 			continue;
 		}
-
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		SetPageLRU(page);
 		lru = page_lru(page);
-		add_page_to_lru_list(page, lruvec, lru);
 
-		if (is_active_lru(lru)) {
-			int file = is_file_lru(lru);
-			int numpages = hpage_nr_pages(page);
-			reclaim_stat->recent_rotated[file] += numpages;
-		}
+		nr_pages = thp_nr_pages(page);
+		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
+		list_move(&page->lru, &lruvec->lists[lru]);
+		trace_android_vh_add_page_to_lrulist(page, false, lru);
+
 		if (put_page_testzero(page)) {
 			__ClearPageLRU(page);
 			__ClearPageActive(page);
@@ -1861,29 +1944,34 @@
 
 			if (unlikely(PageCompound(page))) {
 				spin_unlock_irq(&pgdat->lru_lock);
-				mem_cgroup_uncharge(page);
-				(*get_compound_page_dtor(page))(page);
+				destroy_compound_page(page);
 				spin_lock_irq(&pgdat->lru_lock);
 			} else
 				list_add(&page->lru, &pages_to_free);
+		} else {
+			nr_moved += nr_pages;
+			if (PageActive(page))
+				workingset_age_nonresident(lruvec, nr_pages);
 		}
 	}
 
 	/*
 	 * To save our caller's stack, now use input list for pages to free.
 	 */
-	list_splice(&pages_to_free, page_list);
+	list_splice(&pages_to_free, list);
+
+	return nr_moved;
 }
 
 /*
  * If a kernel thread (such as nfsd for loop-back mounts) services
- * a backing device by writing to the page cache it sets PF_LESS_THROTTLE.
+ * a backing device by writing to the page cache it sets PF_LOCAL_THROTTLE.
  * In that case we should only throttle if the backing device it is
  * writing to is congested.  In other cases it is safe to throttle.
  */
 static int current_may_throttle(void)
 {
-	return !(current->flags & PF_LESS_THROTTLE) ||
+	return !(current->flags & PF_LOCAL_THROTTLE) ||
 		current->backing_dev_info == NULL ||
 		bdi_write_congested(current->backing_dev_info);
 }
@@ -1898,13 +1986,12 @@
 {
 	LIST_HEAD(page_list);
 	unsigned long nr_scanned;
-	unsigned long nr_reclaimed = 0;
+	unsigned int nr_reclaimed = 0;
 	unsigned long nr_taken;
-	struct reclaim_stat stat = {};
-	isolate_mode_t isolate_mode = 0;
-	int file = is_file_lru(lru);
+	struct reclaim_stat stat;
+	bool file = is_file_lru(lru);
+	enum vm_event_item item;
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 	bool stalled = false;
 
 	while (unlikely(too_many_isolated(pgdat, file, sc))) {
@@ -1922,54 +2009,37 @@
 
 	lru_add_drain();
 
-	if (!sc->may_unmap)
-		isolate_mode |= ISOLATE_UNMAPPED;
-
 	spin_lock_irq(&pgdat->lru_lock);
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &page_list,
-				     &nr_scanned, sc, isolate_mode, lru);
+				     &nr_scanned, sc, lru);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, nr_taken);
-	reclaim_stat->recent_scanned[file] += nr_taken;
+	item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT;
+	if (!cgroup_reclaim(sc))
+		__count_vm_events(item, nr_scanned);
+	__count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
+	__count_vm_events(PGSCAN_ANON + file, nr_scanned);
 
-	if (current_is_kswapd()) {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSCAN_KSWAPD, nr_scanned);
-		count_memcg_events(lruvec_memcg(lruvec), PGSCAN_KSWAPD,
-				   nr_scanned);
-	} else {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSCAN_DIRECT, nr_scanned);
-		count_memcg_events(lruvec_memcg(lruvec), PGSCAN_DIRECT,
-				   nr_scanned);
-	}
 	spin_unlock_irq(&pgdat->lru_lock);
 
 	if (nr_taken == 0)
 		return 0;
 
-	nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, 0,
-				&stat, false);
+	nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, &stat, false);
+	trace_android_vh_handle_failed_page_trylock(&page_list);
 
 	spin_lock_irq(&pgdat->lru_lock);
 
-	if (current_is_kswapd()) {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSTEAL_KSWAPD, nr_reclaimed);
-		count_memcg_events(lruvec_memcg(lruvec), PGSTEAL_KSWAPD,
-				   nr_reclaimed);
-	} else {
-		if (global_reclaim(sc))
-			__count_vm_events(PGSTEAL_DIRECT, nr_reclaimed);
-		count_memcg_events(lruvec_memcg(lruvec), PGSTEAL_DIRECT,
-				   nr_reclaimed);
-	}
-
-	putback_inactive_pages(lruvec, &page_list);
+	move_pages_to_lru(lruvec, &page_list);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
-
+	lru_note_cost(lruvec, file, stat.nr_pageout);
+	item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
+	if (!cgroup_reclaim(sc))
+		__count_vm_events(item, nr_reclaimed);
+	__count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
+	__count_vm_events(PGSTEAL_ANON + file, nr_reclaimed);
 	spin_unlock_irq(&pgdat->lru_lock);
 
 	mem_cgroup_uncharge_list(&page_list);
@@ -2003,73 +2073,6 @@
 	return nr_reclaimed;
 }
 
-/*
- * This moves pages from the active list to the inactive list.
- *
- * We move them the other way if the page is referenced by one or more
- * processes, from rmap.
- *
- * If the pages are mostly unmapped, the processing is fast and it is
- * appropriate to hold zone_lru_lock across the whole operation.  But if
- * the pages are mapped, the processing is slow (page_referenced()) so we
- * should drop zone_lru_lock around each page.  It's impossible to balance
- * this, so instead we remove the pages from the LRU while processing them.
- * It is safe to rely on PG_active against the non-LRU pages in here because
- * nobody will play with that bit on a non-LRU page.
- *
- * The downside is that we have to touch page->_refcount against each page.
- * But we had to alter page->flags anyway.
- *
- * Returns the number of pages moved to the given lru.
- */
-
-static unsigned move_active_pages_to_lru(struct lruvec *lruvec,
-				     struct list_head *list,
-				     struct list_head *pages_to_free,
-				     enum lru_list lru)
-{
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-	struct page *page;
-	int nr_pages;
-	int nr_moved = 0;
-
-	while (!list_empty(list)) {
-		page = lru_to_page(list);
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-
-		VM_BUG_ON_PAGE(PageLRU(page), page);
-		SetPageLRU(page);
-
-		nr_pages = hpage_nr_pages(page);
-		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
-		list_move(&page->lru, &lruvec->lists[lru]);
-
-		if (put_page_testzero(page)) {
-			__ClearPageLRU(page);
-			__ClearPageActive(page);
-			del_page_from_lru_list(page, lruvec, lru);
-
-			if (unlikely(PageCompound(page))) {
-				spin_unlock_irq(&pgdat->lru_lock);
-				mem_cgroup_uncharge(page);
-				(*get_compound_page_dtor(page))(page);
-				spin_lock_irq(&pgdat->lru_lock);
-			} else
-				list_add(&page->lru, pages_to_free);
-		} else {
-			nr_moved += nr_pages;
-		}
-	}
-
-	if (!is_active_lru(lru)) {
-		__count_vm_events(PGDEACTIVATE, nr_moved);
-		count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
-				   nr_moved);
-	}
-
-	return nr_moved;
-}
-
 static void shrink_active_list(unsigned long nr_to_scan,
 			       struct lruvec *lruvec,
 			       struct scan_control *sc,
@@ -2082,28 +2085,25 @@
 	LIST_HEAD(l_active);
 	LIST_HEAD(l_inactive);
 	struct page *page;
-	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 	unsigned nr_deactivate, nr_activate;
 	unsigned nr_rotated = 0;
-	isolate_mode_t isolate_mode = 0;
 	int file = is_file_lru(lru);
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
+	bool bypass = false;
+	bool should_protect = false;
 
 	lru_add_drain();
-
-	if (!sc->may_unmap)
-		isolate_mode |= ISOLATE_UNMAPPED;
 
 	spin_lock_irq(&pgdat->lru_lock);
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &l_hold,
-				     &nr_scanned, sc, isolate_mode, lru);
+				     &nr_scanned, sc, lru);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, nr_taken);
-	reclaim_stat->recent_scanned[file] += nr_taken;
 
-	__count_vm_events(PGREFILL, nr_scanned);
-	count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
+	if (!cgroup_reclaim(sc))
+		__count_vm_events(PGREFILL, nr_scanned);
+	__count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
 
 	spin_unlock_irq(&pgdat->lru_lock);
 
@@ -2125,9 +2125,20 @@
 			}
 		}
 
+		trace_android_vh_page_should_be_protected(page, &should_protect);
+		if (unlikely(should_protect)) {
+			nr_rotated += thp_nr_pages(page);
+			list_add(&page->lru, &l_active);
+			continue;
+		}
+
+		trace_android_vh_page_referenced_check_bypass(page, nr_to_scan, lru, &bypass);
+		if (bypass)
+			goto skip_page_referenced;
+		trace_android_vh_page_trylock_set(page);
+		/* Referenced or rmap lock contention: rotate */
 		if (page_referenced(page, 0, sc->target_mem_cgroup,
-				    &vm_flags)) {
-			nr_rotated += hpage_nr_pages(page);
+				     &vm_flags) != 0) {
 			/*
 			 * Identify referenced, file-backed active pages and
 			 * give them one more trip around the active list. So
@@ -2137,12 +2148,15 @@
 			 * IO, plus JVM can create lots of anon VM_EXEC pages,
 			 * so we ignore them here.
 			 */
-			if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) {
+			if ((vm_flags & VM_EXEC) && page_is_file_lru(page)) {
+				trace_android_vh_page_trylock_clear(page);
+				nr_rotated += thp_nr_pages(page);
 				list_add(&page->lru, &l_active);
 				continue;
 			}
 		}
-
+		trace_android_vh_page_trylock_clear(page);
+skip_page_referenced:
 		ClearPageActive(page);	/* we are de-activating */
 		SetPageWorkingset(page);
 		list_add(&page->lru, &l_inactive);
@@ -2152,23 +2166,91 @@
 	 * Move pages back to the lru list.
 	 */
 	spin_lock_irq(&pgdat->lru_lock);
-	/*
-	 * Count referenced pages from currently used mappings as rotated,
-	 * even though only some of them are actually re-activated.  This
-	 * helps balance scan pressure between file and anonymous pages in
-	 * get_scan_count.
-	 */
-	reclaim_stat->recent_rotated[file] += nr_rotated;
 
-	nr_activate = move_active_pages_to_lru(lruvec, &l_active, &l_hold, lru);
-	nr_deactivate = move_active_pages_to_lru(lruvec, &l_inactive, &l_hold, lru - LRU_ACTIVE);
+	nr_activate = move_pages_to_lru(lruvec, &l_active);
+	nr_deactivate = move_pages_to_lru(lruvec, &l_inactive);
+	/* Keep all free pages in l_active list */
+	list_splice(&l_inactive, &l_active);
+
+	__count_vm_events(PGDEACTIVATE, nr_deactivate);
+	__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate);
+
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
 	spin_unlock_irq(&pgdat->lru_lock);
 
-	mem_cgroup_uncharge_list(&l_hold);
-	free_unref_page_list(&l_hold);
+	mem_cgroup_uncharge_list(&l_active);
+	free_unref_page_list(&l_active);
 	trace_mm_vmscan_lru_shrink_active(pgdat->node_id, nr_taken, nr_activate,
 			nr_deactivate, nr_rotated, sc->priority, file);
+}
+
+unsigned long reclaim_pages(struct list_head *page_list)
+{
+	int nid = NUMA_NO_NODE;
+	unsigned int nr_reclaimed = 0;
+	LIST_HEAD(node_page_list);
+	struct reclaim_stat dummy_stat;
+	struct page *page;
+	struct scan_control sc = {
+		.gfp_mask = GFP_KERNEL,
+		.priority = DEF_PRIORITY,
+		.may_writepage = 1,
+		.may_unmap = 1,
+		.may_swap = 1,
+	};
+
+	while (!list_empty(page_list)) {
+		page = lru_to_page(page_list);
+		if (nid == NUMA_NO_NODE) {
+			nid = page_to_nid(page);
+			INIT_LIST_HEAD(&node_page_list);
+		}
+
+		if (nid == page_to_nid(page)) {
+			ClearPageActive(page);
+			list_move(&page->lru, &node_page_list);
+			continue;
+		}
+
+		nr_reclaimed += shrink_page_list(&node_page_list,
+						NODE_DATA(nid),
+						&sc, &dummy_stat, false);
+		while (!list_empty(&node_page_list)) {
+			page = lru_to_page(&node_page_list);
+			list_del(&page->lru);
+			putback_lru_page(page);
+		}
+
+		nid = NUMA_NO_NODE;
+	}
+
+	if (!list_empty(&node_page_list)) {
+		nr_reclaimed += shrink_page_list(&node_page_list,
+						NODE_DATA(nid),
+						&sc, &dummy_stat, false);
+		while (!list_empty(&node_page_list)) {
+			page = lru_to_page(&node_page_list);
+			list_del(&page->lru);
+			putback_lru_page(page);
+		}
+	}
+
+	return nr_reclaimed;
+}
+EXPORT_SYMBOL_GPL(reclaim_pages);
+
+static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
+				 struct lruvec *lruvec, struct scan_control *sc)
+{
+	if (is_active_lru(lru)) {
+		if (sc->may_deactivate & (1 << is_file_lru(lru)))
+			shrink_active_list(nr_to_scan, lruvec, sc, lru);
+		else
+			sc->skipped_deactivate = 1;
+		return 0;
+	}
+
+	return shrink_inactive_list(nr_to_scan, lruvec, sc, lru);
 }
 
 /*
@@ -2199,62 +2281,31 @@
  *    1TB     101        10GB
  *   10TB     320        32GB
  */
-static bool inactive_list_is_low(struct lruvec *lruvec, bool file,
-				 struct scan_control *sc, bool trace)
+static bool inactive_is_low(struct lruvec *lruvec, enum lru_list inactive_lru)
 {
-	enum lru_list active_lru = file * LRU_FILE + LRU_ACTIVE;
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-	enum lru_list inactive_lru = file * LRU_FILE;
+	enum lru_list active_lru = inactive_lru + LRU_ACTIVE;
 	unsigned long inactive, active;
 	unsigned long inactive_ratio;
-	unsigned long refaults;
 	unsigned long gb;
+	bool skip = false;
 
-	/*
-	 * If we don't have swap space, anonymous page deactivation
-	 * is pointless.
-	 */
-	if (!file && !total_swap_pages)
-		return false;
+	inactive = lruvec_page_state(lruvec, NR_LRU_BASE + inactive_lru);
+	active = lruvec_page_state(lruvec, NR_LRU_BASE + active_lru);
 
-	inactive = lruvec_lru_size(lruvec, inactive_lru, sc->reclaim_idx);
-	active = lruvec_lru_size(lruvec, active_lru, sc->reclaim_idx);
+	gb = (inactive + active) >> (30 - PAGE_SHIFT);
+	trace_android_vh_inactive_is_low(gb, &inactive_ratio, inactive_lru, &skip);
+	if (skip)
+		goto out;
 
-	/*
-	 * When refaults are being observed, it means a new workingset
-	 * is being established. Disable active list protection to get
-	 * rid of the stale workingset quickly.
-	 */
-	refaults = lruvec_page_state(lruvec, WORKINGSET_ACTIVATE);
-	if (file && lruvec->refaults != refaults) {
-		inactive_ratio = 0;
-	} else {
-		gb = (inactive + active) >> (30 - PAGE_SHIFT);
-		if (gb)
-			inactive_ratio = int_sqrt(10 * gb);
-		else
-			inactive_ratio = 1;
-	}
+	if (gb)
+		inactive_ratio = int_sqrt(10 * gb);
+	else
+		inactive_ratio = 1;
 
-	if (trace)
-		trace_mm_vmscan_inactive_list_is_low(pgdat->node_id, sc->reclaim_idx,
-			lruvec_lru_size(lruvec, inactive_lru, MAX_NR_ZONES), inactive,
-			lruvec_lru_size(lruvec, active_lru, MAX_NR_ZONES), active,
-			inactive_ratio, file);
+	trace_android_vh_tune_inactive_ratio(&inactive_ratio, is_file_lru(inactive_lru));
 
+out:
 	return inactive * inactive_ratio < active;
-}
-
-static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
-				 struct lruvec *lruvec, struct scan_control *sc)
-{
-	if (is_active_lru(lru)) {
-		if (inactive_list_is_low(lruvec, is_file_lru(lru), sc, true))
-			shrink_active_list(nr_to_scan, lruvec, sc, lru);
-		return 0;
-	}
-
-	return shrink_inactive_list(nr_to_scan, lruvec, sc, lru);
 }
 
 enum scan_balance {
@@ -2273,20 +2324,18 @@
  * nr[0] = anon inactive pages to scan; nr[1] = anon active pages to scan
  * nr[2] = file inactive pages to scan; nr[3] = file active pages to scan
  */
-static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
-			   struct scan_control *sc, unsigned long *nr,
-			   unsigned long *lru_pages)
+static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
+			   unsigned long *nr)
 {
+	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+	unsigned long anon_cost, file_cost, total_cost;
 	int swappiness = mem_cgroup_swappiness(memcg);
-	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
-	u64 fraction[2];
+	u64 fraction[ANON_AND_FILE];
 	u64 denominator = 0;	/* gcc */
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-	unsigned long anon_prio, file_prio;
 	enum scan_balance scan_balance;
-	unsigned long anon, file;
 	unsigned long ap, fp;
 	enum lru_list lru;
+	bool balance_anon_file_reclaim = false;
 
 	/* If we have no swap space, do not bother scanning anon pages. */
 	if (!sc->may_swap || mem_cgroup_get_nr_swap_pages(memcg) <= 0) {
@@ -2294,6 +2343,7 @@
 		goto out;
 	}
 
+	trace_android_vh_tune_swappiness(&swappiness);
 	/*
 	 * Global reclaim will swap to prevent OOM even with no
 	 * swappiness, but memcg users want to use this knob to
@@ -2301,7 +2351,7 @@
 	 * using the memory controller's swap limit feature would be
 	 * too expensive.
 	 */
-	if (!global_reclaim(sc) && !swappiness) {
+	if (cgroup_reclaim(sc) && !swappiness) {
 		scan_balance = SCAN_FILE;
 		goto out;
 	}
@@ -2317,129 +2367,133 @@
 	}
 
 	/*
-	 * Prevent the reclaimer from falling into the cache trap: as
-	 * cache pages start out inactive, every cache fault will tip
-	 * the scan balance towards the file LRU.  And as the file LRU
-	 * shrinks, so does the window for rotation from references.
-	 * This means we have a runaway feedback loop where a tiny
-	 * thrashing file LRU becomes infinitely more attractive than
-	 * anon pages.  Try to detect this based on file LRU size.
+	 * If the system is almost out of file pages, force-scan anon.
 	 */
-	if (global_reclaim(sc)) {
-		unsigned long pgdatfile;
-		unsigned long pgdatfree;
-		int z;
-		unsigned long total_high_wmark = 0;
-
-		pgdatfree = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES);
-		pgdatfile = node_page_state(pgdat, NR_ACTIVE_FILE) +
-			   node_page_state(pgdat, NR_INACTIVE_FILE);
-
-		for (z = 0; z < MAX_NR_ZONES; z++) {
-			struct zone *zone = &pgdat->node_zones[z];
-			if (!managed_zone(zone))
-				continue;
-
-			total_high_wmark += high_wmark_pages(zone);
-		}
-
-		if (unlikely(pgdatfile + pgdatfree <= total_high_wmark)) {
-			/*
-			 * Force SCAN_ANON if there are enough inactive
-			 * anonymous pages on the LRU in eligible zones.
-			 * Otherwise, the small LRU gets thrashed.
-			 */
-			if (!inactive_list_is_low(lruvec, false, sc, false) &&
-			    lruvec_lru_size(lruvec, LRU_INACTIVE_ANON, sc->reclaim_idx)
-					>> sc->priority) {
-				scan_balance = SCAN_ANON;
-				goto out;
-			}
-		}
+	if (sc->file_is_tiny) {
+		scan_balance = SCAN_ANON;
+		goto out;
 	}
 
+	trace_android_rvh_set_balance_anon_file_reclaim(&balance_anon_file_reclaim);
+
 	/*
-	 * If there is enough inactive page cache, i.e. if the size of the
-	 * inactive list is greater than that of the active list *and* the
-	 * inactive list actually has some pages to scan on this priority, we
-	 * do not reclaim anything from the anonymous working set right now.
-	 * Without the second condition we could end up never scanning an
-	 * lruvec even if it has plenty of old anonymous pages unless the
-	 * system is under heavy pressure.
+	 * If there is enough inactive page cache, we do not reclaim
+	 * anything from the anonymous working right now. But when balancing
+	 * anon and page cache files for reclaim, allow swapping of anon pages
+	 * even if there are a number of inactive file cache pages.
 	 */
-	if (!inactive_list_is_low(lruvec, true, sc, false) &&
-	    lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, sc->reclaim_idx) >> sc->priority) {
+	if (!balance_anon_file_reclaim && sc->cache_trim_mode) {
 		scan_balance = SCAN_FILE;
 		goto out;
 	}
 
 	scan_balance = SCAN_FRACT;
-
 	/*
-	 * With swappiness at 100, anonymous and file have the same priority.
-	 * This scanning priority is essentially the inverse of IO cost.
-	 */
-	anon_prio = swappiness;
-	file_prio = 200 - anon_prio;
-
-	/*
-	 * OK, so we have swap space and a fair amount of page cache
-	 * pages.  We use the recently rotated / recently scanned
-	 * ratios to determine how valuable each cache is.
+	 * Calculate the pressure balance between anon and file pages.
 	 *
-	 * Because workloads change over time (and to avoid overflow)
-	 * we keep these statistics as a floating average, which ends
-	 * up weighing recent references more than old ones.
+	 * The amount of pressure we put on each LRU is inversely
+	 * proportional to the cost of reclaiming each list, as
+	 * determined by the share of pages that are refaulting, times
+	 * the relative IO cost of bringing back a swapped out
+	 * anonymous page vs reloading a filesystem page (swappiness).
 	 *
-	 * anon in [0], file in [1]
+	 * Although we limit that influence to ensure no list gets
+	 * left behind completely: at least a third of the pressure is
+	 * applied, before swappiness.
+	 *
+	 * With swappiness at 100, anon and file have equal IO cost.
 	 */
+	total_cost = sc->anon_cost + sc->file_cost;
+	anon_cost = total_cost + sc->anon_cost;
+	file_cost = total_cost + sc->file_cost;
+	total_cost = anon_cost + file_cost;
 
-	anon  = lruvec_lru_size(lruvec, LRU_ACTIVE_ANON, MAX_NR_ZONES) +
-		lruvec_lru_size(lruvec, LRU_INACTIVE_ANON, MAX_NR_ZONES);
-	file  = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES) +
-		lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES);
+	ap = swappiness * (total_cost + 1);
+	ap /= anon_cost + 1;
 
-	spin_lock_irq(&pgdat->lru_lock);
-	if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
-		reclaim_stat->recent_scanned[0] /= 2;
-		reclaim_stat->recent_rotated[0] /= 2;
-	}
-
-	if (unlikely(reclaim_stat->recent_scanned[1] > file / 4)) {
-		reclaim_stat->recent_scanned[1] /= 2;
-		reclaim_stat->recent_rotated[1] /= 2;
-	}
-
-	/*
-	 * The amount of pressure on anon vs file pages is inversely
-	 * proportional to the fraction of recently scanned pages on
-	 * each list that were recently referenced and in active use.
-	 */
-	ap = anon_prio * (reclaim_stat->recent_scanned[0] + 1);
-	ap /= reclaim_stat->recent_rotated[0] + 1;
-
-	fp = file_prio * (reclaim_stat->recent_scanned[1] + 1);
-	fp /= reclaim_stat->recent_rotated[1] + 1;
-	spin_unlock_irq(&pgdat->lru_lock);
+	fp = (200 - swappiness) * (total_cost + 1);
+	fp /= file_cost + 1;
 
 	fraction[0] = ap;
 	fraction[1] = fp;
-	denominator = ap + fp + 1;
+	denominator = ap + fp;
 out:
-	*lru_pages = 0;
+	trace_android_vh_tune_scan_type((char *)(&scan_balance));
 	for_each_evictable_lru(lru) {
 		int file = is_file_lru(lru);
-		unsigned long size;
+		unsigned long lruvec_size;
+		unsigned long low, min;
 		unsigned long scan;
 
-		size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx);
-		scan = size >> sc->priority;
+		lruvec_size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx);
+		mem_cgroup_protection(sc->target_mem_cgroup, memcg,
+				      &min, &low);
+
+		if (min || low) {
+			/*
+			 * Scale a cgroup's reclaim pressure by proportioning
+			 * its current usage to its memory.low or memory.min
+			 * setting.
+			 *
+			 * This is important, as otherwise scanning aggression
+			 * becomes extremely binary -- from nothing as we
+			 * approach the memory protection threshold, to totally
+			 * nominal as we exceed it.  This results in requiring
+			 * setting extremely liberal protection thresholds. It
+			 * also means we simply get no protection at all if we
+			 * set it too low, which is not ideal.
+			 *
+			 * If there is any protection in place, we reduce scan
+			 * pressure by how much of the total memory used is
+			 * within protection thresholds.
+			 *
+			 * There is one special case: in the first reclaim pass,
+			 * we skip over all groups that are within their low
+			 * protection. If that fails to reclaim enough pages to
+			 * satisfy the reclaim goal, we come back and override
+			 * the best-effort low protection. However, we still
+			 * ideally want to honor how well-behaved groups are in
+			 * that case instead of simply punishing them all
+			 * equally. As such, we reclaim them based on how much
+			 * memory they are using, reducing the scan pressure
+			 * again by how much of the total memory used is under
+			 * hard protection.
+			 */
+			unsigned long cgroup_size = mem_cgroup_size(memcg);
+			unsigned long protection;
+
+			/* memory.low scaling, make sure we retry before OOM */
+			if (!sc->memcg_low_reclaim && low > min) {
+				protection = low;
+				sc->memcg_low_skipped = 1;
+			} else {
+				protection = min;
+			}
+
+			/* Avoid TOCTOU with earlier protection check */
+			cgroup_size = max(cgroup_size, protection);
+
+			scan = lruvec_size - lruvec_size * protection /
+				(cgroup_size + 1);
+
+			/*
+			 * Minimally target SWAP_CLUSTER_MAX pages to keep
+			 * reclaim moving forwards, avoiding decrementing
+			 * sc->priority further than desirable.
+			 */
+			scan = max(scan, SWAP_CLUSTER_MAX);
+		} else {
+			scan = lruvec_size;
+		}
+
+		scan >>= sc->priority;
+
 		/*
 		 * If the cgroup's already been deleted, make sure to
 		 * scrape out the remaining cache.
 		 */
 		if (!scan && !mem_cgroup_online(memcg))
-			scan = min(size, SWAP_CLUSTER_MAX);
+			scan = min(lruvec_size, SWAP_CLUSTER_MAX);
 
 		switch (scan_balance) {
 		case SCAN_EQUAL:
@@ -2461,38 +2515,30 @@
 		case SCAN_FILE:
 		case SCAN_ANON:
 			/* Scan one type exclusively */
-			if ((scan_balance == SCAN_FILE) != file) {
-				size = 0;
+			if ((scan_balance == SCAN_FILE) != file)
 				scan = 0;
-			}
 			break;
 		default:
 			/* Look ma, no brain */
 			BUG();
 		}
 
-		*lru_pages += size;
 		nr[lru] = scan;
 	}
 }
 
-/*
- * This is a basic per-node page freer.  Used by both kswapd and direct reclaim.
- */
-static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memcg,
-			      struct scan_control *sc, unsigned long *lru_pages)
+static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
 {
-	struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, memcg);
 	unsigned long nr[NR_LRU_LISTS];
 	unsigned long targets[NR_LRU_LISTS];
 	unsigned long nr_to_scan;
 	enum lru_list lru;
 	unsigned long nr_reclaimed = 0;
 	unsigned long nr_to_reclaim = sc->nr_to_reclaim;
+	bool proportional_reclaim;
 	struct blk_plug plug;
-	bool scan_adjusted;
 
-	get_scan_count(lruvec, memcg, sc, nr, lru_pages);
+	get_scan_count(lruvec, sc, nr);
 
 	/* Record the original scan target for proportional adjustments later */
 	memcpy(targets, nr, sizeof(nr));
@@ -2508,8 +2554,8 @@
 	 * abort proportional reclaim if either the file or anon lru has already
 	 * dropped to zero at the first pass.
 	 */
-	scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() &&
-			 sc->priority == DEF_PRIORITY);
+	proportional_reclaim = (!cgroup_reclaim(sc) && !current_is_kswapd() &&
+				sc->priority == DEF_PRIORITY);
 
 	blk_start_plug(&plug);
 	while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
@@ -2529,7 +2575,7 @@
 
 		cond_resched();
 
-		if (nr_reclaimed < nr_to_reclaim || scan_adjusted)
+		if (nr_reclaimed < nr_to_reclaim || proportional_reclaim)
 			continue;
 
 		/*
@@ -2580,8 +2626,6 @@
 		nr_scanned = targets[lru] - nr[lru];
 		nr[lru] = targets[lru] * (100 - percentage) / 100;
 		nr[lru] -= min(nr[lru], nr_scanned);
-
-		scan_adjusted = true;
 	}
 	blk_finish_plug(&plug);
 	sc->nr_reclaimed += nr_reclaimed;
@@ -2590,7 +2634,7 @@
 	 * Even if we did not try to evict anon pages at all, we want to
 	 * rebalance the anon lru active/inactive ratio.
 	 */
-	if (inactive_list_is_low(lruvec, false, sc, true))
+	if (total_swap_pages && inactive_is_low(lruvec, LRU_INACTIVE_ANON))
 		shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
 				   sc, LRU_ACTIVE_ANON);
 }
@@ -2610,12 +2654,11 @@
  * Reclaim/compaction is used for high-order allocation requests. It reclaims
  * order-0 pages before compacting the zone. should_continue_reclaim() returns
  * true if more pages should be reclaimed such that when the page allocator
- * calls try_to_compact_zone() that it will have enough free pages to succeed.
+ * calls try_to_compact_pages() that it will have enough free pages to succeed.
  * It will give up earlier than that if there is difficulty reclaiming pages.
  */
 static inline bool should_continue_reclaim(struct pglist_data *pgdat,
 					unsigned long nr_reclaimed,
-					unsigned long nr_scanned,
 					struct scan_control *sc)
 {
 	unsigned long pages_for_compaction;
@@ -2626,40 +2669,18 @@
 	if (!in_reclaim_compaction(sc))
 		return false;
 
-	/* Consider stopping depending on scan and reclaim activity */
-	if (sc->gfp_mask & __GFP_RETRY_MAYFAIL) {
-		/*
-		 * For __GFP_RETRY_MAYFAIL allocations, stop reclaiming if the
-		 * full LRU list has been scanned and we are still failing
-		 * to reclaim pages. This full LRU scan is potentially
-		 * expensive but a __GFP_RETRY_MAYFAIL caller really wants to succeed
-		 */
-		if (!nr_reclaimed && !nr_scanned)
-			return false;
-	} else {
-		/*
-		 * For non-__GFP_RETRY_MAYFAIL allocations which can presumably
-		 * fail without consequence, stop if we failed to reclaim
-		 * any pages from the last SWAP_CLUSTER_MAX number of
-		 * pages that were scanned. This will return to the
-		 * caller faster at the risk reclaim/compaction and
-		 * the resulting allocation attempt fails
-		 */
-		if (!nr_reclaimed)
-			return false;
-	}
-
 	/*
-	 * If we have not reclaimed enough pages for compaction and the
-	 * inactive lists are large enough, continue reclaiming
+	 * Stop if we failed to reclaim any pages from the last SWAP_CLUSTER_MAX
+	 * number of pages that were scanned. This will return to the caller
+	 * with the risk reclaim/compaction and the resulting allocation attempt
+	 * fails. In the past we have tried harder for __GFP_RETRY_MAYFAIL
+	 * allocations through requiring that the full LRU list has been scanned
+	 * first, by assuming that zero delta of sc->nr_scanned means full LRU
+	 * scan, but that approximation was wrong, and there were corner cases
+	 * where always a non-zero amount of pages were scanned.
 	 */
-	pages_for_compaction = compact_gap(sc->order);
-	inactive_lru_pages = node_page_state(pgdat, NR_INACTIVE_FILE);
-	if (get_nr_swap_pages() > 0)
-		inactive_lru_pages += node_page_state(pgdat, NR_INACTIVE_ANON);
-	if (sc->nr_reclaimed < pages_for_compaction &&
-			inactive_lru_pages > pages_for_compaction)
-		return true;
+	if (!nr_reclaimed)
+		return false;
 
 	/* If compaction would go ahead or the allocation would succeed, stop */
 	for (z = 0; z <= sc->reclaim_idx; z++) {
@@ -2676,179 +2697,262 @@
 			;
 		}
 	}
-	return true;
+
+	/*
+	 * If we have not reclaimed enough pages for compaction and the
+	 * inactive lists are large enough, continue reclaiming
+	 */
+	pages_for_compaction = compact_gap(sc->order);
+	inactive_lru_pages = node_page_state(pgdat, NR_INACTIVE_FILE);
+	if (get_nr_swap_pages() > 0)
+		inactive_lru_pages += node_page_state(pgdat, NR_INACTIVE_ANON);
+
+	return inactive_lru_pages > pages_for_compaction;
 }
 
-static bool pgdat_memcg_congested(pg_data_t *pgdat, struct mem_cgroup *memcg)
+static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc)
 {
-	return test_bit(PGDAT_CONGESTED, &pgdat->flags) ||
-		(memcg && memcg_congested(pgdat, memcg));
+	struct mem_cgroup *target_memcg = sc->target_mem_cgroup;
+	struct mem_cgroup *memcg;
+
+	memcg = mem_cgroup_iter(target_memcg, NULL, NULL);
+	do {
+		struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
+		unsigned long reclaimed;
+		unsigned long scanned;
+		bool skip = false;
+
+		/*
+		 * This loop can become CPU-bound when target memcgs
+		 * aren't eligible for reclaim - either because they
+		 * don't have any reclaimable pages, or because their
+		 * memory is explicitly protected. Avoid soft lockups.
+		 */
+		cond_resched();
+
+		trace_android_vh_shrink_node_memcgs(memcg, &skip);
+		if (skip)
+			continue;
+
+		mem_cgroup_calculate_protection(target_memcg, memcg);
+
+		if (mem_cgroup_below_min(memcg)) {
+			/*
+			 * Hard protection.
+			 * If there is no reclaimable memory, OOM.
+			 */
+			continue;
+		} else if (mem_cgroup_below_low(memcg)) {
+			/*
+			 * Soft protection.
+			 * Respect the protection only as long as
+			 * there is an unprotected supply
+			 * of reclaimable memory from other cgroups.
+			 */
+			if (!sc->memcg_low_reclaim) {
+				sc->memcg_low_skipped = 1;
+				continue;
+			}
+			memcg_memory_event(memcg, MEMCG_LOW);
+		}
+
+		reclaimed = sc->nr_reclaimed;
+		scanned = sc->nr_scanned;
+
+		shrink_lruvec(lruvec, sc);
+
+		shrink_slab(sc->gfp_mask, pgdat->node_id, memcg,
+			    sc->priority);
+
+		/* Record the group's reclaim efficiency */
+		vmpressure(sc->gfp_mask, memcg, false,
+			   sc->nr_scanned - scanned,
+			   sc->nr_reclaimed - reclaimed);
+
+	} while ((memcg = mem_cgroup_iter(target_memcg, memcg, NULL)));
 }
 
-static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
+static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
 {
 	struct reclaim_state *reclaim_state = current->reclaim_state;
 	unsigned long nr_reclaimed, nr_scanned;
+	struct lruvec *target_lruvec;
 	bool reclaimable = false;
+	unsigned long file;
 
-	do {
-		struct mem_cgroup *root = sc->target_mem_cgroup;
-		struct mem_cgroup_reclaim_cookie reclaim = {
-			.pgdat = pgdat,
-			.priority = sc->priority,
-		};
-		unsigned long node_lru_pages = 0;
-		struct mem_cgroup *memcg;
+	target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat);
 
-		memset(&sc->nr, 0, sizeof(sc->nr));
+again:
+	memset(&sc->nr, 0, sizeof(sc->nr));
 
-		nr_reclaimed = sc->nr_reclaimed;
-		nr_scanned = sc->nr_scanned;
+	nr_reclaimed = sc->nr_reclaimed;
+	nr_scanned = sc->nr_scanned;
 
-		memcg = mem_cgroup_iter(root, NULL, &reclaim);
-		do {
-			unsigned long lru_pages;
-			unsigned long reclaimed;
-			unsigned long scanned;
+	/*
+	 * Determine the scan balance between anon and file LRUs.
+	 */
+	spin_lock_irq(&pgdat->lru_lock);
+	sc->anon_cost = target_lruvec->anon_cost;
+	sc->file_cost = target_lruvec->file_cost;
+	spin_unlock_irq(&pgdat->lru_lock);
 
-			/*
-			 * This loop can become CPU-bound when target memcgs
-			 * aren't eligible for reclaim - either because they
-			 * don't have any reclaimable pages, or because their
-			 * memory is explicitly protected. Avoid soft lockups.
-			 */
-			cond_resched();
+	/*
+	 * Target desirable inactive:active list ratios for the anon
+	 * and file LRU lists.
+	 */
+	if (!sc->force_deactivate) {
+		unsigned long refaults;
 
-			switch (mem_cgroup_protected(root, memcg)) {
-			case MEMCG_PROT_MIN:
-				/*
-				 * Hard protection.
-				 * If there is no reclaimable memory, OOM.
-				 */
+		refaults = lruvec_page_state(target_lruvec,
+				WORKINGSET_ACTIVATE_ANON);
+		if (refaults != target_lruvec->refaults[0] ||
+			inactive_is_low(target_lruvec, LRU_INACTIVE_ANON))
+			sc->may_deactivate |= DEACTIVATE_ANON;
+		else
+			sc->may_deactivate &= ~DEACTIVATE_ANON;
+
+		/*
+		 * When refaults are being observed, it means a new
+		 * workingset is being established. Deactivate to get
+		 * rid of any stale active pages quickly.
+		 */
+		refaults = lruvec_page_state(target_lruvec,
+				WORKINGSET_ACTIVATE_FILE);
+		if (refaults != target_lruvec->refaults[1] ||
+		    inactive_is_low(target_lruvec, LRU_INACTIVE_FILE))
+			sc->may_deactivate |= DEACTIVATE_FILE;
+		else
+			sc->may_deactivate &= ~DEACTIVATE_FILE;
+	} else
+		sc->may_deactivate = DEACTIVATE_ANON | DEACTIVATE_FILE;
+
+	/*
+	 * If we have plenty of inactive file pages that aren't
+	 * thrashing, try to reclaim those first before touching
+	 * anonymous pages.
+	 */
+	file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE);
+	if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE))
+		sc->cache_trim_mode = 1;
+	else
+		sc->cache_trim_mode = 0;
+
+	/*
+	 * Prevent the reclaimer from falling into the cache trap: as
+	 * cache pages start out inactive, every cache fault will tip
+	 * the scan balance towards the file LRU.  And as the file LRU
+	 * shrinks, so does the window for rotation from references.
+	 * This means we have a runaway feedback loop where a tiny
+	 * thrashing file LRU becomes infinitely more attractive than
+	 * anon pages.  Try to detect this based on file LRU size.
+	 */
+	if (!cgroup_reclaim(sc)) {
+		unsigned long total_high_wmark = 0;
+		unsigned long free, anon;
+		int z;
+
+		free = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES);
+		file = node_page_state(pgdat, NR_ACTIVE_FILE) +
+			   node_page_state(pgdat, NR_INACTIVE_FILE);
+
+		for (z = 0; z < MAX_NR_ZONES; z++) {
+			struct zone *zone = &pgdat->node_zones[z];
+			if (!managed_zone(zone))
 				continue;
-			case MEMCG_PROT_LOW:
-				/*
-				 * Soft protection.
-				 * Respect the protection only as long as
-				 * there is an unprotected supply
-				 * of reclaimable memory from other cgroups.
-				 */
-				if (!sc->memcg_low_reclaim) {
-					sc->memcg_low_skipped = 1;
-					continue;
-				}
-				memcg_memory_event(memcg, MEMCG_LOW);
-				break;
-			case MEMCG_PROT_NONE:
-				break;
-			}
 
-			reclaimed = sc->nr_reclaimed;
-			scanned = sc->nr_scanned;
-			shrink_node_memcg(pgdat, memcg, sc, &lru_pages);
-			node_lru_pages += lru_pages;
-
-			shrink_slab(sc->gfp_mask, pgdat->node_id,
-				    memcg, sc->priority);
-
-			/* Record the group's reclaim efficiency */
-			vmpressure(sc->gfp_mask, memcg, false,
-				   sc->nr_scanned - scanned,
-				   sc->nr_reclaimed - reclaimed);
-
-			/*
-			 * Direct reclaim and kswapd have to scan all memory
-			 * cgroups to fulfill the overall scan target for the
-			 * node.
-			 *
-			 * Limit reclaim, on the other hand, only cares about
-			 * nr_to_reclaim pages to be reclaimed and it will
-			 * retry with decreasing priority if one round over the
-			 * whole hierarchy is not sufficient.
-			 */
-			if (!global_reclaim(sc) &&
-					sc->nr_reclaimed >= sc->nr_to_reclaim) {
-				mem_cgroup_iter_break(root, memcg);
-				break;
-			}
-		} while ((memcg = mem_cgroup_iter(root, memcg, &reclaim)));
-
-		if (reclaim_state) {
-			sc->nr_reclaimed += reclaim_state->reclaimed_slab;
-			reclaim_state->reclaimed_slab = 0;
-		}
-
-		/* Record the subtree's reclaim efficiency */
-		vmpressure(sc->gfp_mask, sc->target_mem_cgroup, true,
-			   sc->nr_scanned - nr_scanned,
-			   sc->nr_reclaimed - nr_reclaimed);
-
-		if (sc->nr_reclaimed - nr_reclaimed)
-			reclaimable = true;
-
-		if (current_is_kswapd()) {
-			/*
-			 * If reclaim is isolating dirty pages under writeback,
-			 * it implies that the long-lived page allocation rate
-			 * is exceeding the page laundering rate. Either the
-			 * global limits are not being effective at throttling
-			 * processes due to the page distribution throughout
-			 * zones or there is heavy usage of a slow backing
-			 * device. The only option is to throttle from reclaim
-			 * context which is not ideal as there is no guarantee
-			 * the dirtying process is throttled in the same way
-			 * balance_dirty_pages() manages.
-			 *
-			 * Once a node is flagged PGDAT_WRITEBACK, kswapd will
-			 * count the number of pages under pages flagged for
-			 * immediate reclaim and stall if any are encountered
-			 * in the nr_immediate check below.
-			 */
-			if (sc->nr.writeback && sc->nr.writeback == sc->nr.taken)
-				set_bit(PGDAT_WRITEBACK, &pgdat->flags);
-
-			/*
-			 * Tag a node as congested if all the dirty pages
-			 * scanned were backed by a congested BDI and
-			 * wait_iff_congested will stall.
-			 */
-			if (sc->nr.dirty && sc->nr.dirty == sc->nr.congested)
-				set_bit(PGDAT_CONGESTED, &pgdat->flags);
-
-			/* Allow kswapd to start writing pages during reclaim.*/
-			if (sc->nr.unqueued_dirty == sc->nr.file_taken)
-				set_bit(PGDAT_DIRTY, &pgdat->flags);
-
-			/*
-			 * If kswapd scans pages marked marked for immediate
-			 * reclaim and under writeback (nr_immediate), it
-			 * implies that pages are cycling through the LRU
-			 * faster than they are written so also forcibly stall.
-			 */
-			if (sc->nr.immediate)
-				congestion_wait(BLK_RW_ASYNC, HZ/10);
+			total_high_wmark += high_wmark_pages(zone);
 		}
 
 		/*
-		 * Legacy memcg will stall in page writeback so avoid forcibly
-		 * stalling in wait_iff_congested().
+		 * Consider anon: if that's low too, this isn't a
+		 * runaway file reclaim problem, but rather just
+		 * extreme pressure. Reclaim as per usual then.
 		 */
-		if (!global_reclaim(sc) && sane_reclaim(sc) &&
-		    sc->nr.dirty && sc->nr.dirty == sc->nr.congested)
-			set_memcg_congestion(pgdat, root, true);
+		anon = node_page_state(pgdat, NR_INACTIVE_ANON);
+
+		sc->file_is_tiny =
+			file + free <= total_high_wmark &&
+			!(sc->may_deactivate & DEACTIVATE_ANON) &&
+			anon >> sc->priority;
+	}
+
+	shrink_node_memcgs(pgdat, sc);
+
+	if (reclaim_state) {
+		sc->nr_reclaimed += reclaim_state->reclaimed_slab;
+		reclaim_state->reclaimed_slab = 0;
+	}
+
+	/* Record the subtree's reclaim efficiency */
+	vmpressure(sc->gfp_mask, sc->target_mem_cgroup, true,
+		   sc->nr_scanned - nr_scanned,
+		   sc->nr_reclaimed - nr_reclaimed);
+
+	if (sc->nr_reclaimed - nr_reclaimed)
+		reclaimable = true;
+
+	if (current_is_kswapd()) {
+		/*
+		 * If reclaim is isolating dirty pages under writeback,
+		 * it implies that the long-lived page allocation rate
+		 * is exceeding the page laundering rate. Either the
+		 * global limits are not being effective at throttling
+		 * processes due to the page distribution throughout
+		 * zones or there is heavy usage of a slow backing
+		 * device. The only option is to throttle from reclaim
+		 * context which is not ideal as there is no guarantee
+		 * the dirtying process is throttled in the same way
+		 * balance_dirty_pages() manages.
+		 *
+		 * Once a node is flagged PGDAT_WRITEBACK, kswapd will
+		 * count the number of pages under pages flagged for
+		 * immediate reclaim and stall if any are encountered
+		 * in the nr_immediate check below.
+		 */
+		if (sc->nr.writeback && sc->nr.writeback == sc->nr.taken)
+			set_bit(PGDAT_WRITEBACK, &pgdat->flags);
+
+		/* Allow kswapd to start writing pages during reclaim.*/
+		if (sc->nr.unqueued_dirty == sc->nr.file_taken)
+			set_bit(PGDAT_DIRTY, &pgdat->flags);
 
 		/*
-		 * Stall direct reclaim for IO completions if underlying BDIs
-		 * and node is congested. Allow kswapd to continue until it
-		 * starts encountering unqueued dirty pages or cycling through
-		 * the LRU too quickly.
+		 * If kswapd scans pages marked for immediate
+		 * reclaim and under writeback (nr_immediate), it
+		 * implies that pages are cycling through the LRU
+		 * faster than they are written so also forcibly stall.
 		 */
-		if (!sc->hibernation_mode && !current_is_kswapd() &&
-		   current_may_throttle() && pgdat_memcg_congested(pgdat, root))
-			wait_iff_congested(BLK_RW_ASYNC, HZ/10);
+		if (sc->nr.immediate)
+			congestion_wait(BLK_RW_ASYNC, HZ/10);
+	}
 
-	} while (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,
-					 sc->nr_scanned - nr_scanned, sc));
+	/*
+	 * Tag a node/memcg as congested if all the dirty pages
+	 * scanned were backed by a congested BDI and
+	 * wait_iff_congested will stall.
+	 *
+	 * Legacy memcg will stall in page writeback so avoid forcibly
+	 * stalling in wait_iff_congested().
+	 */
+	if ((current_is_kswapd() ||
+	     (cgroup_reclaim(sc) && writeback_throttling_sane(sc))) &&
+	    sc->nr.dirty && sc->nr.dirty == sc->nr.congested)
+		set_bit(LRUVEC_CONGESTED, &target_lruvec->flags);
+
+	/*
+	 * Stall direct reclaim for IO completions if underlying BDIs
+	 * and node is congested. Allow kswapd to continue until it
+	 * starts encountering unqueued dirty pages or cycling through
+	 * the LRU too quickly.
+	 */
+	if (!current_is_kswapd() && current_may_throttle() &&
+	    !sc->hibernation_mode &&
+	    test_bit(LRUVEC_CONGESTED, &target_lruvec->flags))
+		wait_iff_congested(BLK_RW_ASYNC, HZ/10);
+
+	if (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,
+				    sc))
+		goto again;
 
 	/*
 	 * Kswapd gives up on balancing particular nodes after too
@@ -2858,8 +2962,6 @@
 	 */
 	if (reclaimable)
 		pgdat->kswapd_failures = 0;
-
-	return reclaimable;
 }
 
 /*
@@ -2928,7 +3030,7 @@
 		 * Take care memory controller reclaiming has small influence
 		 * to global LRU.
 		 */
-		if (global_reclaim(sc)) {
+		if (!cgroup_reclaim(sc)) {
 			if (!cpuset_zone_allowed(zone,
 						 GFP_KERNEL | __GFP_HARDWALL))
 				continue;
@@ -2987,19 +3089,17 @@
 	sc->gfp_mask = orig_mask;
 }
 
-static void snapshot_refaults(struct mem_cgroup *root_memcg, pg_data_t *pgdat)
+static void snapshot_refaults(struct mem_cgroup *target_memcg, pg_data_t *pgdat)
 {
-	struct mem_cgroup *memcg;
+	struct lruvec *target_lruvec;
+	unsigned long refaults;
 
-	memcg = mem_cgroup_iter(root_memcg, NULL, NULL);
-	do {
-		unsigned long refaults;
-		struct lruvec *lruvec;
-
-		lruvec = mem_cgroup_lruvec(pgdat, memcg);
-		refaults = lruvec_page_state(lruvec, WORKINGSET_ACTIVATE);
-		lruvec->refaults = refaults;
-	} while ((memcg = mem_cgroup_iter(root_memcg, memcg, NULL)));
+	target_lruvec = mem_cgroup_lruvec(target_memcg, pgdat);
+	refaults = lruvec_page_state(target_lruvec, WORKINGSET_ACTIVATE_ANON);
+	target_lruvec->refaults[0] = refaults;
+	refaults = lruvec_page_state(target_lruvec, WORKINGSET_ACTIVATE_FILE);
+	target_lruvec->refaults[1] = refaults;
+	trace_android_vh_snapshot_refaults(target_lruvec);
 }
 
 /*
@@ -3028,7 +3128,7 @@
 retry:
 	delayacct_freepages_start();
 
-	if (global_reclaim(sc))
+	if (!cgroup_reclaim(sc))
 		__count_zid_vm_events(ALLOCSTALL, sc->reclaim_idx, 1);
 
 	do {
@@ -3057,8 +3157,16 @@
 		if (zone->zone_pgdat == last_pgdat)
 			continue;
 		last_pgdat = zone->zone_pgdat;
+
 		snapshot_refaults(sc->target_mem_cgroup, zone->zone_pgdat);
-		set_memcg_congestion(last_pgdat, sc->target_mem_cgroup, false);
+
+		if (cgroup_reclaim(sc)) {
+			struct lruvec *lruvec;
+
+			lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup,
+						   zone->zone_pgdat);
+			clear_bit(LRUVEC_CONGESTED, &lruvec->flags);
+		}
 	}
 
 	delayacct_freepages_end();
@@ -3070,9 +3178,26 @@
 	if (sc->compaction_ready)
 		return 1;
 
+	/*
+	 * We make inactive:active ratio decisions based on the node's
+	 * composition of memory, but a restrictive reclaim_idx or a
+	 * memory.low cgroup setting can exempt large amounts of
+	 * memory from reclaim. Neither of which are very common, so
+	 * instead of doing costly eligibility calculations of the
+	 * entire cgroup subtree up front, we assume the estimates are
+	 * good, and retry with forcible deactivation if that fails.
+	 */
+	if (sc->skipped_deactivate) {
+		sc->priority = initial_priority;
+		sc->force_deactivate = 1;
+		sc->skipped_deactivate = 0;
+		goto retry;
+	}
+
 	/* Untapped cgroup reserves?  Don't OOM, retry. */
 	if (sc->memcg_low_skipped) {
 		sc->priority = initial_priority;
+		sc->force_deactivate = 0;
 		sc->memcg_low_reclaim = 1;
 		sc->memcg_low_skipped = 0;
 		goto retry;
@@ -3112,8 +3237,8 @@
 
 	/* kswapd must be awake if processes are being throttled */
 	if (!wmark_ok && waitqueue_active(&pgdat->kswapd_wait)) {
-		if (READ_ONCE(pgdat->kswapd_classzone_idx) > ZONE_NORMAL)
-			WRITE_ONCE(pgdat->kswapd_classzone_idx, ZONE_NORMAL);
+		if (READ_ONCE(pgdat->kswapd_highest_zoneidx) > ZONE_NORMAL)
+			WRITE_ONCE(pgdat->kswapd_highest_zoneidx, ZONE_NORMAL);
 
 		wake_up_interruptible(&pgdat->kswapd_wait);
 	}
@@ -3246,25 +3371,26 @@
 	if (throttle_direct_reclaim(sc.gfp_mask, zonelist, nodemask))
 		return 1;
 
-	trace_mm_vmscan_direct_reclaim_begin(order,
-				sc.may_writepage,
-				sc.gfp_mask,
-				sc.reclaim_idx);
+	set_task_reclaim_state(current, &sc.reclaim_state);
+	trace_mm_vmscan_direct_reclaim_begin(order, sc.gfp_mask);
 
 	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
 	trace_mm_vmscan_direct_reclaim_end(nr_reclaimed);
+	set_task_reclaim_state(current, NULL);
 
 	return nr_reclaimed;
 }
 
 #ifdef CONFIG_MEMCG
 
+/* Only used by soft limit reclaim. Do not reuse for anything else. */
 unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
 						gfp_t gfp_mask, bool noswap,
 						pg_data_t *pgdat,
 						unsigned long *nr_scanned)
 {
+	struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
 	struct scan_control sc = {
 		.nr_to_reclaim = SWAP_CLUSTER_MAX,
 		.target_mem_cgroup = memcg,
@@ -3273,15 +3399,14 @@
 		.reclaim_idx = MAX_NR_ZONES - 1,
 		.may_swap = !noswap,
 	};
-	unsigned long lru_pages;
+
+	WARN_ON_ONCE(!current->reclaim_state);
 
 	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
 			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_begin(sc.order,
-						      sc.may_writepage,
-						      sc.gfp_mask,
-						      sc.reclaim_idx);
+						      sc.gfp_mask);
 
 	/*
 	 * NOTE: Although we can get the priority field, using it
@@ -3290,11 +3415,12 @@
 	 * will pick up pages from other mem cgroup's as well. We hack
 	 * the priority and make it zero.
 	 */
-	shrink_node_memcg(pgdat, memcg, &sc, &lru_pages);
+	shrink_lruvec(lruvec, &sc);
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
 
 	*nr_scanned = sc.nr_scanned;
+
 	return sc.nr_reclaimed;
 }
 
@@ -3303,10 +3429,7 @@
 					   gfp_t gfp_mask,
 					   bool may_swap)
 {
-	struct zonelist *zonelist;
 	unsigned long nr_reclaimed;
-	unsigned long pflags;
-	int nid;
 	unsigned int noreclaim_flag;
 	struct scan_control sc = {
 		.nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX),
@@ -3319,78 +3442,101 @@
 		.may_unmap = 1,
 		.may_swap = may_swap,
 	};
-
 	/*
-	 * Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't
-	 * take care of from where we get pages. So the node where we start the
-	 * scan does not need to be the current node.
+	 * Traverse the ZONELIST_FALLBACK zonelist of the current node to put
+	 * equal pressure on all the nodes. This is based on the assumption that
+	 * the reclaim does not bail out early.
 	 */
-	nid = mem_cgroup_select_victim_node(memcg);
+	struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
 
-	zonelist = &NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK];
-
-	trace_mm_vmscan_memcg_reclaim_begin(0,
-					    sc.may_writepage,
-					    sc.gfp_mask,
-					    sc.reclaim_idx);
-
-	psi_memstall_enter(&pflags);
+	set_task_reclaim_state(current, &sc.reclaim_state);
+	trace_mm_vmscan_memcg_reclaim_begin(0, sc.gfp_mask);
 	noreclaim_flag = memalloc_noreclaim_save();
 
 	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
 	memalloc_noreclaim_restore(noreclaim_flag);
-	psi_memstall_leave(&pflags);
-
 	trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
+	set_task_reclaim_state(current, NULL);
 
 	return nr_reclaimed;
 }
+EXPORT_SYMBOL_GPL(try_to_free_mem_cgroup_pages);
 #endif
 
 static void age_active_anon(struct pglist_data *pgdat,
 				struct scan_control *sc)
 {
 	struct mem_cgroup *memcg;
+	struct lruvec *lruvec;
 
 	if (!total_swap_pages)
 		return;
 
+	lruvec = mem_cgroup_lruvec(NULL, pgdat);
+	if (!inactive_is_low(lruvec, LRU_INACTIVE_ANON))
+		return;
+
 	memcg = mem_cgroup_iter(NULL, NULL, NULL);
 	do {
-		struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, memcg);
-
-		if (inactive_list_is_low(lruvec, false, sc, true))
-			shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
-					   sc, LRU_ACTIVE_ANON);
-
+		lruvec = mem_cgroup_lruvec(memcg, pgdat);
+		shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
+				   sc, LRU_ACTIVE_ANON);
 		memcg = mem_cgroup_iter(NULL, memcg, NULL);
 	} while (memcg);
 }
 
+static bool pgdat_watermark_boosted(pg_data_t *pgdat, int highest_zoneidx)
+{
+	int i;
+	struct zone *zone;
+
+	/*
+	 * Check for watermark boosts top-down as the higher zones
+	 * are more likely to be boosted. Both watermarks and boosts
+	 * should not be checked at the same time as reclaim would
+	 * start prematurely when there is no boosting and a lower
+	 * zone is balanced.
+	 */
+	for (i = highest_zoneidx; i >= 0; i--) {
+		zone = pgdat->node_zones + i;
+		if (!managed_zone(zone))
+			continue;
+
+		if (zone->watermark_boost)
+			return true;
+	}
+
+	return false;
+}
+
 /*
  * Returns true if there is an eligible zone balanced for the request order
- * and classzone_idx
+ * and highest_zoneidx
  */
-static bool pgdat_balanced(pg_data_t *pgdat, int order, int classzone_idx)
+static bool pgdat_balanced(pg_data_t *pgdat, int order, int highest_zoneidx)
 {
 	int i;
 	unsigned long mark = -1;
 	struct zone *zone;
 
-	for (i = 0; i <= classzone_idx; i++) {
+	/*
+	 * Check watermarks bottom-up as lower zones are more likely to
+	 * meet watermarks.
+	 */
+	for (i = 0; i <= highest_zoneidx; i++) {
 		zone = pgdat->node_zones + i;
 
 		if (!managed_zone(zone))
 			continue;
 
 		mark = high_wmark_pages(zone);
-		if (zone_watermark_ok_safe(zone, order, mark, classzone_idx))
+		if (zone_watermark_ok_safe(zone, order, mark, highest_zoneidx))
 			return true;
 	}
 
 	/*
-	 * If a node has no populated zone within classzone_idx, it does not
+	 * If a node has no populated zone within highest_zoneidx, it does not
 	 * need balancing by definition. This can happen if a zone-restricted
 	 * allocation tries to wake a remote kswapd.
 	 */
@@ -3403,7 +3549,9 @@
 /* Clear pgdat state for congested, dirty or under writeback. */
 static void clear_pgdat_congested(pg_data_t *pgdat)
 {
-	clear_bit(PGDAT_CONGESTED, &pgdat->flags);
+	struct lruvec *lruvec = mem_cgroup_lruvec(NULL, pgdat);
+
+	clear_bit(LRUVEC_CONGESTED, &lruvec->flags);
 	clear_bit(PGDAT_DIRTY, &pgdat->flags);
 	clear_bit(PGDAT_WRITEBACK, &pgdat->flags);
 }
@@ -3414,7 +3562,8 @@
  *
  * Returns true if kswapd is ready to sleep
  */
-static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, int classzone_idx)
+static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order,
+				int highest_zoneidx)
 {
 	/*
 	 * The throttled processes are normally woken up in balance_pgdat() as
@@ -3436,7 +3585,7 @@
 	if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES)
 		return true;
 
-	if (pgdat_balanced(pgdat, order, classzone_idx)) {
+	if (pgdat_balanced(pgdat, order, highest_zoneidx)) {
 		clear_pgdat_congested(pgdat);
 		return true;
 	}
@@ -3496,37 +3645,57 @@
  *
  * kswapd scans the zones in the highmem->normal->dma direction.  It skips
  * zones which have free_pages > high_wmark_pages(zone), but once a zone is
- * found to have free_pages <= high_wmark_pages(zone), any page is that zone
+ * found to have free_pages <= high_wmark_pages(zone), any page in that zone
  * or lower is eligible for reclaim until at least one usable zone is
  * balanced.
  */
-static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
+static int balance_pgdat(pg_data_t *pgdat, int order, int highest_zoneidx)
 {
 	int i;
 	unsigned long nr_soft_reclaimed;
 	unsigned long nr_soft_scanned;
 	unsigned long pflags;
+	unsigned long nr_boost_reclaim;
+	unsigned long zone_boosts[MAX_NR_ZONES] = { 0, };
+	bool boosted;
 	struct zone *zone;
 	struct scan_control sc = {
 		.gfp_mask = GFP_KERNEL,
 		.order = order,
-		.priority = DEF_PRIORITY,
-		.may_writepage = !laptop_mode,
 		.may_unmap = 1,
-		.may_swap = 1,
 	};
 
+	set_task_reclaim_state(current, &sc.reclaim_state);
 	psi_memstall_enter(&pflags);
 	__fs_reclaim_acquire();
 
 	count_vm_event(PAGEOUTRUN);
 
+	/*
+	 * Account for the reclaim boost. Note that the zone boost is left in
+	 * place so that parallel allocations that are near the watermark will
+	 * stall or direct reclaim until kswapd is finished.
+	 */
+	nr_boost_reclaim = 0;
+	for (i = 0; i <= highest_zoneidx; i++) {
+		zone = pgdat->node_zones + i;
+		if (!managed_zone(zone))
+			continue;
+
+		nr_boost_reclaim += zone->watermark_boost;
+		zone_boosts[i] = zone->watermark_boost;
+	}
+	boosted = nr_boost_reclaim;
+
+restart:
+	sc.priority = DEF_PRIORITY;
 	do {
 		unsigned long nr_reclaimed = sc.nr_reclaimed;
 		bool raise_priority = true;
+		bool balanced;
 		bool ret;
 
-		sc.reclaim_idx = classzone_idx;
+		sc.reclaim_idx = highest_zoneidx;
 
 		/*
 		 * If the number of buffer_heads exceeds the maximum allowed
@@ -3550,12 +3719,38 @@
 		}
 
 		/*
-		 * Only reclaim if there are no eligible zones. Note that
-		 * sc.reclaim_idx is not used as buffer_heads_over_limit may
-		 * have adjusted it.
+		 * If the pgdat is imbalanced then ignore boosting and preserve
+		 * the watermarks for a later time and restart. Note that the
+		 * zone watermarks will be still reset at the end of balancing
+		 * on the grounds that the normal reclaim should be enough to
+		 * re-evaluate if boosting is required when kswapd next wakes.
 		 */
-		if (pgdat_balanced(pgdat, sc.order, classzone_idx))
+		balanced = pgdat_balanced(pgdat, sc.order, highest_zoneidx);
+		if (!balanced && nr_boost_reclaim) {
+			nr_boost_reclaim = 0;
+			goto restart;
+		}
+
+		/*
+		 * If boosting is not active then only reclaim if there are no
+		 * eligible zones. Note that sc.reclaim_idx is not used as
+		 * buffer_heads_over_limit may have adjusted it.
+		 */
+		if (!nr_boost_reclaim && balanced)
 			goto out;
+
+		/* Limit the priority of boosting to avoid reclaim writeback */
+		if (nr_boost_reclaim && sc.priority == DEF_PRIORITY - 2)
+			raise_priority = false;
+
+		/*
+		 * Do not writeback or swap pages for boosted reclaim. The
+		 * intent is to relieve pressure not issue sub-optimal IO
+		 * from reclaim context. If no pages are reclaimed, the
+		 * reclaim will be aborted.
+		 */
+		sc.may_writepage = !laptop_mode && !nr_boost_reclaim;
+		sc.may_swap = !nr_boost_reclaim;
 
 		/*
 		 * Do some background aging of the anon list, to give
@@ -3608,6 +3803,16 @@
 		 * progress in reclaiming pages
 		 */
 		nr_reclaimed = sc.nr_reclaimed - nr_reclaimed;
+		nr_boost_reclaim -= min(nr_boost_reclaim, nr_reclaimed);
+
+		/*
+		 * If reclaim made no progress for a boost, stop reclaim as
+		 * IO cannot be queued and it could be an infinite loop in
+		 * extreme circumstances.
+		 */
+		if (nr_boost_reclaim && !nr_reclaimed)
+			break;
+
 		if (raise_priority || !nr_reclaimed)
 			sc.priority--;
 	} while (sc.priority >= 1);
@@ -3616,9 +3821,33 @@
 		pgdat->kswapd_failures++;
 
 out:
+	/* If reclaim was boosted, account for the reclaim done in this pass */
+	if (boosted) {
+		unsigned long flags;
+
+		for (i = 0; i <= highest_zoneidx; i++) {
+			if (!zone_boosts[i])
+				continue;
+
+			/* Increments are under the zone lock */
+			zone = pgdat->node_zones + i;
+			spin_lock_irqsave(&zone->lock, flags);
+			zone->watermark_boost -= min(zone->watermark_boost, zone_boosts[i]);
+			spin_unlock_irqrestore(&zone->lock, flags);
+		}
+
+		/*
+		 * As there is now likely space, wakeup kcompact to defragment
+		 * pageblocks.
+		 */
+		wakeup_kcompactd(pgdat, pageblock_order, highest_zoneidx);
+	}
+
 	snapshot_refaults(NULL, pgdat);
 	__fs_reclaim_release();
 	psi_memstall_leave(&pflags);
+	set_task_reclaim_state(current, NULL);
+
 	/*
 	 * Return the order kswapd stopped reclaiming at as
 	 * prepare_kswapd_sleep() takes it into account. If another caller
@@ -3629,22 +3858,22 @@
 }
 
 /*
- * The pgdat->kswapd_classzone_idx is used to pass the highest zone index to be
- * reclaimed by kswapd from the waker. If the value is MAX_NR_ZONES which is not
- * a valid index then either kswapd runs for first time or kswapd couldn't sleep
- * after previous reclaim attempt (node is still unbalanced). In that case
- * return the zone index of the previous kswapd reclaim cycle.
+ * The pgdat->kswapd_highest_zoneidx is used to pass the highest zone index to
+ * be reclaimed by kswapd from the waker. If the value is MAX_NR_ZONES which is
+ * not a valid index then either kswapd runs for first time or kswapd couldn't
+ * sleep after previous reclaim attempt (node is still unbalanced). In that
+ * case return the zone index of the previous kswapd reclaim cycle.
  */
-static enum zone_type kswapd_classzone_idx(pg_data_t *pgdat,
-					   enum zone_type prev_classzone_idx)
+static enum zone_type kswapd_highest_zoneidx(pg_data_t *pgdat,
+					   enum zone_type prev_highest_zoneidx)
 {
-	enum zone_type curr_idx = READ_ONCE(pgdat->kswapd_classzone_idx);
+	enum zone_type curr_idx = READ_ONCE(pgdat->kswapd_highest_zoneidx);
 
-	return curr_idx == MAX_NR_ZONES ? prev_classzone_idx : curr_idx;
+	return curr_idx == MAX_NR_ZONES ? prev_highest_zoneidx : curr_idx;
 }
 
 static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_order,
-				unsigned int classzone_idx)
+				unsigned int highest_zoneidx)
 {
 	long remaining = 0;
 	DEFINE_WAIT(wait);
@@ -3661,7 +3890,7 @@
 	 * eligible zone balanced that it's also unlikely that compaction will
 	 * succeed.
 	 */
-	if (prepare_kswapd_sleep(pgdat, reclaim_order, classzone_idx)) {
+	if (prepare_kswapd_sleep(pgdat, reclaim_order, highest_zoneidx)) {
 		/*
 		 * Compaction records what page blocks it recently failed to
 		 * isolate pages from and skips them in the future scanning.
@@ -3674,18 +3903,19 @@
 		 * We have freed the memory, now we should compact it to make
 		 * allocation of the requested order possible.
 		 */
-		wakeup_kcompactd(pgdat, alloc_order, classzone_idx);
+		wakeup_kcompactd(pgdat, alloc_order, highest_zoneidx);
 
 		remaining = schedule_timeout(HZ/10);
 
 		/*
-		 * If woken prematurely then reset kswapd_classzone_idx and
+		 * If woken prematurely then reset kswapd_highest_zoneidx and
 		 * order. The values will either be from a wakeup request or
 		 * the previous request that slept prematurely.
 		 */
 		if (remaining) {
-			WRITE_ONCE(pgdat->kswapd_classzone_idx,
-				   kswapd_classzone_idx(pgdat, classzone_idx));
+			WRITE_ONCE(pgdat->kswapd_highest_zoneidx,
+					kswapd_highest_zoneidx(pgdat,
+							highest_zoneidx));
 
 			if (READ_ONCE(pgdat->kswapd_order) < reclaim_order)
 				WRITE_ONCE(pgdat->kswapd_order, reclaim_order);
@@ -3700,7 +3930,7 @@
 	 * go fully to sleep until explicitly woken up.
 	 */
 	if (!remaining &&
-	    prepare_kswapd_sleep(pgdat, reclaim_order, classzone_idx)) {
+	    prepare_kswapd_sleep(pgdat, reclaim_order, highest_zoneidx)) {
 		trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
 
 		/*
@@ -3742,18 +3972,13 @@
 static int kswapd(void *p)
 {
 	unsigned int alloc_order, reclaim_order;
-	unsigned int classzone_idx = MAX_NR_ZONES - 1;
+	unsigned int highest_zoneidx = MAX_NR_ZONES - 1;
 	pg_data_t *pgdat = (pg_data_t*)p;
 	struct task_struct *tsk = current;
-
-	struct reclaim_state reclaim_state = {
-		.reclaimed_slab = 0,
-	};
 	const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
 
 	if (!cpumask_empty(cpumask))
 		set_cpus_allowed_ptr(tsk, cpumask);
-	current->reclaim_state = &reclaim_state;
 
 	/*
 	 * Tell the memory management that we're a "memory allocator",
@@ -3771,22 +3996,24 @@
 	set_freezable();
 
 	WRITE_ONCE(pgdat->kswapd_order, 0);
-	WRITE_ONCE(pgdat->kswapd_classzone_idx, MAX_NR_ZONES);
+	WRITE_ONCE(pgdat->kswapd_highest_zoneidx, MAX_NR_ZONES);
 	for ( ; ; ) {
 		bool ret;
 
 		alloc_order = reclaim_order = READ_ONCE(pgdat->kswapd_order);
-		classzone_idx = kswapd_classzone_idx(pgdat, classzone_idx);
+		highest_zoneidx = kswapd_highest_zoneidx(pgdat,
+							highest_zoneidx);
 
 kswapd_try_sleep:
 		kswapd_try_to_sleep(pgdat, alloc_order, reclaim_order,
-					classzone_idx);
+					highest_zoneidx);
 
-		/* Read the new order and classzone_idx */
+		/* Read the new order and highest_zoneidx */
 		alloc_order = reclaim_order = READ_ONCE(pgdat->kswapd_order);
-		classzone_idx = kswapd_classzone_idx(pgdat, classzone_idx);
+		highest_zoneidx = kswapd_highest_zoneidx(pgdat,
+							highest_zoneidx);
 		WRITE_ONCE(pgdat->kswapd_order, 0);
-		WRITE_ONCE(pgdat->kswapd_classzone_idx, MAX_NR_ZONES);
+		WRITE_ONCE(pgdat->kswapd_highest_zoneidx, MAX_NR_ZONES);
 
 		ret = try_to_freeze();
 		if (kthread_should_stop())
@@ -3807,17 +4034,57 @@
 		 * but kcompactd is woken to compact for the original
 		 * request (alloc_order).
 		 */
-		trace_mm_vmscan_kswapd_wake(pgdat->node_id, classzone_idx,
+		trace_mm_vmscan_kswapd_wake(pgdat->node_id, highest_zoneidx,
 						alloc_order);
-		reclaim_order = balance_pgdat(pgdat, alloc_order, classzone_idx);
+		reclaim_order = balance_pgdat(pgdat, alloc_order,
+						highest_zoneidx);
 		if (reclaim_order < alloc_order)
 			goto kswapd_try_sleep;
 	}
 
 	tsk->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD);
-	current->reclaim_state = NULL;
 
 	return 0;
+}
+
+static int kswapd_per_node_run(int nid)
+{
+	pg_data_t *pgdat = NODE_DATA(nid);
+	int hid;
+	int ret = 0;
+
+	for (hid = 0; hid < kswapd_threads; ++hid) {
+		pgdat->mkswapd[hid] = kthread_run(kswapd, pgdat, "kswapd%d:%d",
+								nid, hid);
+		if (IS_ERR(pgdat->mkswapd[hid])) {
+			/* failure at boot is fatal */
+			WARN_ON(system_state < SYSTEM_RUNNING);
+			pr_err("Failed to start kswapd%d on node %d\n",
+				hid, nid);
+			ret = PTR_ERR(pgdat->mkswapd[hid]);
+			pgdat->mkswapd[hid] = NULL;
+			continue;
+		}
+		if (!pgdat->kswapd)
+			pgdat->kswapd = pgdat->mkswapd[hid];
+	}
+
+	return ret;
+}
+
+static void kswapd_per_node_stop(int nid)
+{
+	int hid = 0;
+	struct task_struct *kswapd;
+
+	for (hid = 0; hid < kswapd_threads; hid++) {
+		kswapd = NODE_DATA(nid)->mkswapd[hid];
+		if (kswapd) {
+			kthread_stop(kswapd);
+			NODE_DATA(nid)->mkswapd[hid] = NULL;
+		}
+	}
+	NODE_DATA(nid)->kswapd = NULL;
 }
 
 /*
@@ -3828,7 +4095,7 @@
  * needed.
  */
 void wakeup_kswapd(struct zone *zone, gfp_t gfp_flags, int order,
-		   enum zone_type classzone_idx)
+		   enum zone_type highest_zoneidx)
 {
 	pg_data_t *pgdat;
 	enum zone_type curr_idx;
@@ -3840,10 +4107,10 @@
 		return;
 
 	pgdat = zone->zone_pgdat;
-	curr_idx = READ_ONCE(pgdat->kswapd_classzone_idx);
+	curr_idx = READ_ONCE(pgdat->kswapd_highest_zoneidx);
 
-	if (curr_idx == MAX_NR_ZONES || curr_idx < classzone_idx)
-		WRITE_ONCE(pgdat->kswapd_classzone_idx, classzone_idx);
+	if (curr_idx == MAX_NR_ZONES || curr_idx < highest_zoneidx)
+		WRITE_ONCE(pgdat->kswapd_highest_zoneidx, highest_zoneidx);
 
 	if (READ_ONCE(pgdat->kswapd_order) < order)
 		WRITE_ONCE(pgdat->kswapd_order, order);
@@ -3853,7 +4120,8 @@
 
 	/* Hopeless node, leave it to direct reclaim if possible */
 	if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ||
-	    pgdat_balanced(pgdat, order, classzone_idx)) {
+	    (pgdat_balanced(pgdat, order, highest_zoneidx) &&
+	     !pgdat_watermark_boosted(pgdat, highest_zoneidx))) {
 		/*
 		 * There may be plenty of free memory available, but it's too
 		 * fragmented for high-order allocations.  Wake up kcompactd
@@ -3862,11 +4130,11 @@
 		 * ratelimit its work.
 		 */
 		if (!(gfp_flags & __GFP_DIRECT_RECLAIM))
-			wakeup_kcompactd(pgdat, order, classzone_idx);
+			wakeup_kcompactd(pgdat, order, highest_zoneidx);
 		return;
 	}
 
-	trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, classzone_idx, order,
+	trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, highest_zoneidx, order,
 				      gfp_flags);
 	wake_up_interruptible(&pgdat->kswapd_wait);
 }
@@ -3882,7 +4150,6 @@
  */
 unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
 {
-	struct reclaim_state reclaim_state;
 	struct scan_control sc = {
 		.nr_to_reclaim = nr_to_reclaim,
 		.gfp_mask = GFP_HIGHUSER_MOVABLE,
@@ -3894,45 +4161,22 @@
 		.hibernation_mode = 1,
 	};
 	struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
-	struct task_struct *p = current;
 	unsigned long nr_reclaimed;
 	unsigned int noreclaim_flag;
 
 	fs_reclaim_acquire(sc.gfp_mask);
 	noreclaim_flag = memalloc_noreclaim_save();
-	reclaim_state.reclaimed_slab = 0;
-	p->reclaim_state = &reclaim_state;
+	set_task_reclaim_state(current, &sc.reclaim_state);
 
 	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
-	p->reclaim_state = NULL;
+	set_task_reclaim_state(current, NULL);
 	memalloc_noreclaim_restore(noreclaim_flag);
 	fs_reclaim_release(sc.gfp_mask);
 
 	return nr_reclaimed;
 }
 #endif /* CONFIG_HIBERNATION */
-
-/* It's optimal to keep kswapds on the same CPUs as their memory, but
-   not required for correctness.  So if the last cpu in a node goes
-   away, we get changed to run anywhere: as the first one comes back,
-   restore their cpu bindings. */
-static int kswapd_cpu_online(unsigned int cpu)
-{
-	int nid;
-
-	for_each_node_state(nid, N_MEMORY) {
-		pg_data_t *pgdat = NODE_DATA(nid);
-		const struct cpumask *mask;
-
-		mask = cpumask_of_node(pgdat->node_id);
-
-		if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
-			/* One of our CPUs online: restore mask */
-			set_cpus_allowed_ptr(pgdat->kswapd, mask);
-	}
-	return 0;
-}
 
 /*
  * This kswapd start function will be called by init and node-hot-add.
@@ -3945,6 +4189,9 @@
 
 	if (pgdat->kswapd)
 		return 0;
+
+	if (kswapd_threads > 1)
+		return kswapd_per_node_run(nid);
 
 	pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid);
 	if (IS_ERR(pgdat->kswapd)) {
@@ -3965,6 +4212,11 @@
 {
 	struct task_struct *kswapd = NODE_DATA(nid)->kswapd;
 
+	if (kswapd_threads > 1) {
+		kswapd_per_node_stop(nid);
+		return;
+	}
+
 	if (kswapd) {
 		kthread_stop(kswapd);
 		NODE_DATA(nid)->kswapd = NULL;
@@ -3973,15 +4225,11 @@
 
 static int __init kswapd_init(void)
 {
-	int nid, ret;
+	int nid;
 
 	swap_setup();
 	for_each_node_state(nid, N_MEMORY)
  		kswapd_run(nid);
-	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
-					"mm/vmscan:online", kswapd_cpu_online,
-					NULL);
-	WARN_ON(ret < 0);
 	return 0;
 }
 
@@ -3996,10 +4244,13 @@
  */
 int node_reclaim_mode __read_mostly;
 
-#define RECLAIM_OFF 0
-#define RECLAIM_ZONE (1<<0)	/* Run shrink_inactive_list on the zone */
-#define RECLAIM_WRITE (1<<1)	/* Writeout pages during reclaim */
-#define RECLAIM_UNMAP (1<<2)	/* Unmap pages during reclaim */
+/*
+ * These bit locations are exposed in the vm.zone_reclaim_mode sysctl
+ * ABI.  New bits are OK, but existing bits can never change.
+ */
+#define RECLAIM_ZONE  (1<<0)   /* Run shrink_inactive_list on the zone */
+#define RECLAIM_WRITE (1<<1)   /* Writeout pages during reclaim */
+#define RECLAIM_UNMAP (1<<2)   /* Unmap pages during reclaim */
 
 /*
  * Priority for NODE_RECLAIM. This determines the fraction of pages
@@ -4070,7 +4321,6 @@
 	/* Minimum pages needed in order to stay on node */
 	const unsigned long nr_pages = 1 << order;
 	struct task_struct *p = current;
-	struct reclaim_state reclaim_state;
 	unsigned int noreclaim_flag;
 	struct scan_control sc = {
 		.nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX),
@@ -4083,6 +4333,9 @@
 		.reclaim_idx = gfp_zone(gfp_mask),
 	};
 
+	trace_mm_vmscan_node_reclaim_begin(pgdat->node_id, order,
+					   sc.gfp_mask);
+
 	cond_resched();
 	fs_reclaim_acquire(sc.gfp_mask);
 	/*
@@ -4092,8 +4345,7 @@
 	 */
 	noreclaim_flag = memalloc_noreclaim_save();
 	p->flags |= PF_SWAPWRITE;
-	reclaim_state.reclaimed_slab = 0;
-	p->reclaim_state = &reclaim_state;
+	set_task_reclaim_state(p, &sc.reclaim_state);
 
 	if (node_pagecache_reclaimable(pgdat) > pgdat->min_unmapped_pages) {
 		/*
@@ -4105,10 +4357,13 @@
 		} while (sc.nr_reclaimed < nr_pages && --sc.priority >= 0);
 	}
 
-	p->reclaim_state = NULL;
+	set_task_reclaim_state(p, NULL);
 	current->flags &= ~PF_SWAPWRITE;
 	memalloc_noreclaim_restore(noreclaim_flag);
 	fs_reclaim_release(sc.gfp_mask);
+
+	trace_mm_vmscan_node_reclaim_end(sc.nr_reclaimed);
+
 	return sc.nr_reclaimed >= nr_pages;
 }
 
@@ -4127,7 +4382,8 @@
 	 * unmapped file backed pages.
 	 */
 	if (node_pagecache_reclaimable(pgdat) <= pgdat->min_unmapped_pages &&
-	    node_page_state(pgdat, NR_SLAB_RECLAIMABLE) <= pgdat->min_slab_pages)
+	    node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B) <=
+	    pgdat->min_slab_pages)
 		return NODE_RECLAIM_FULL;
 
 	/*
@@ -4158,29 +4414,6 @@
 }
 #endif
 
-/*
- * page_evictable - test whether a page is evictable
- * @page: the page to test
- *
- * Test whether page is evictable--i.e., should be placed on active/inactive
- * lists vs unevictable list.
- *
- * Reasons page might not be evictable:
- * (1) page's mapping marked unevictable
- * (2) page is part of an mlocked VMA
- *
- */
-int page_evictable(struct page *page)
-{
-	int ret;
-
-	/* Prevent address_space of inode and swap cache from being freed */
-	rcu_read_lock();
-	ret = !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
-	rcu_read_unlock();
-	return ret;
-}
-
 /**
  * check_move_unevictable_pages - check pages for evictability and move to
  * appropriate zone lru list
@@ -4201,8 +4434,14 @@
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
 		struct pglist_data *pagepgdat = page_pgdat(page);
+		int nr_pages;
 
-		pgscanned++;
+		if (PageTransTail(page))
+			continue;
+
+		nr_pages = thp_nr_pages(page);
+		pgscanned += nr_pages;
+
 		if (pagepgdat != pgdat) {
 			if (pgdat)
 				spin_unlock_irq(&pgdat->lru_lock);
@@ -4221,7 +4460,7 @@
 			ClearPageUnevictable(page);
 			del_page_from_lru_list(page, lruvec, LRU_UNEVICTABLE);
 			add_page_to_lru_list(page, lruvec, lru);
-			pgrescued++;
+			pgrescued += nr_pages;
 		}
 	}
 

--
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