Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1215 insertions, 0 deletions

diff --git a/mm/swap.c b/mm/swap.c
new file mode 100644
index 000000000..47a47681c
--- /dev/null
+++ b/mm/swap.c
@@ -0,0 +1,1215 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/mm/swap.c
+ *
+ *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ */
+
+/*
+ * This file contains the default values for the operation of the
+ * Linux VM subsystem. Fine-tuning documentation can be found in
+ * Documentation/admin-guide/sysctl/vm.rst.
+ * Started 18.12.91
+ * Swap aging added 23.2.95, Stephen Tweedie.
+ * Buffermem limits added 12.3.98, Rik van Riel.
+ */
+
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <linux/swap.h>
+#include <linux/mman.h>
+#include <linux/pagemap.h>
+#include <linux/pagevec.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/mm_inline.h>
+#include <linux/percpu_counter.h>
+#include <linux/memremap.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+#include <linux/backing-dev.h>
+#include <linux/memcontrol.h>
+#include <linux/gfp.h>
+#include <linux/uio.h>
+#include <linux/hugetlb.h>
+#include <linux/page_idle.h>
+#include <linux/local_lock.h>
+
+#include "internal.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/pagemap.h>
+
+/* How many pages do we try to swap or page in/out together? */
+int page_cluster;
+
+/* Protecting only lru_rotate.pvec which requires disabling interrupts */
+struct lru_rotate {
+	local_lock_t lock;
+	struct pagevec pvec;
+};
+static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = {
+	.lock = INIT_LOCAL_LOCK(lock),
+};
+
+/*
+ * The following struct pagevec are grouped together because they are protected
+ * by disabling preemption (and interrupts remain enabled).
+ */
+struct lru_pvecs {
+	local_lock_t lock;
+	struct pagevec lru_add;
+	struct pagevec lru_deactivate_file;
+	struct pagevec lru_deactivate;
+	struct pagevec lru_lazyfree;
+#ifdef CONFIG_SMP
+	struct pagevec activate_page;
+#endif
+};
+static DEFINE_PER_CPU(struct lru_pvecs, lru_pvecs) = {
+	.lock = INIT_LOCAL_LOCK(lock),
+};
+
+/*
+ * This path almost never happens for VM activity - pages are normally
+ * freed via pagevecs.  But it gets used by networking.
+ */
+static void __page_cache_release(struct page *page)
+{
+	if (PageLRU(page)) {
+		pg_data_t *pgdat = page_pgdat(page);
+		struct lruvec *lruvec;
+		unsigned long flags;
+
+		spin_lock_irqsave(&pgdat->lru_lock, flags);
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		VM_BUG_ON_PAGE(!PageLRU(page), page);
+		__ClearPageLRU(page);
+		del_page_from_lru_list(page, lruvec, page_off_lru(page));
+		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	}
+	__ClearPageWaiters(page);
+}
+
+static void __put_single_page(struct page *page)
+{
+	__page_cache_release(page);
+	mem_cgroup_uncharge(page);
+	free_unref_page(page);
+}
+
+static void __put_compound_page(struct page *page)
+{
+	/*
+	 * __page_cache_release() is supposed to be called for thp, not for
+	 * hugetlb. This is because hugetlb page does never have PageLRU set
+	 * (it's never listed to any LRU lists) and no memcg routines should
+	 * be called for hugetlb (it has a separate hugetlb_cgroup.)
+	 */
+	if (!PageHuge(page))
+		__page_cache_release(page);
+	destroy_compound_page(page);
+}
+
+void __put_page(struct page *page)
+{
+	if (is_zone_device_page(page)) {
+		put_dev_pagemap(page->pgmap);
+
+		/*
+		 * The page belongs to the device that created pgmap. Do
+		 * not return it to page allocator.
+		 */
+		return;
+	}
+
+	if (unlikely(PageCompound(page)))
+		__put_compound_page(page);
+	else
+		__put_single_page(page);
+}
+EXPORT_SYMBOL(__put_page);
+
+/**
+ * put_pages_list() - release a list of pages
+ * @pages: list of pages threaded on page->lru
+ *
+ * Release a list of pages which are strung together on page.lru.  Currently
+ * used by read_cache_pages() and related error recovery code.
+ */
+void put_pages_list(struct list_head *pages)
+{
+	while (!list_empty(pages)) {
+		struct page *victim;
+
+		victim = lru_to_page(pages);
+		list_del(&victim->lru);
+		put_page(victim);
+	}
+}
+EXPORT_SYMBOL(put_pages_list);
+
+/*
+ * get_kernel_pages() - pin kernel pages in memory
+ * @kiov:	An array of struct kvec structures
+ * @nr_segs:	number of segments to pin
+ * @write:	pinning for read/write, currently ignored
+ * @pages:	array that receives pointers to the pages pinned.
+ *		Should be at least nr_segs long.
+ *
+ * Returns number of pages pinned. This may be fewer than the number
+ * requested. If nr_pages is 0 or negative, returns 0. If no pages
+ * were pinned, returns -errno. Each page returned must be released
+ * with a put_page() call when it is finished with.
+ */
+int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
+		struct page **pages)
+{
+	int seg;
+
+	for (seg = 0; seg < nr_segs; seg++) {
+		if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
+			return seg;
+
+		pages[seg] = kmap_to_page(kiov[seg].iov_base);
+		get_page(pages[seg]);
+	}
+
+	return seg;
+}
+EXPORT_SYMBOL_GPL(get_kernel_pages);
+
+/*
+ * get_kernel_page() - pin a kernel page in memory
+ * @start:	starting kernel address
+ * @write:	pinning for read/write, currently ignored
+ * @pages:	array that receives pointer to the page pinned.
+ *		Must be at least nr_segs long.
+ *
+ * Returns 1 if page is pinned. If the page was not pinned, returns
+ * -errno. The page returned must be released with a put_page() call
+ * when it is finished with.
+ */
+int get_kernel_page(unsigned long start, int write, struct page **pages)
+{
+	const struct kvec kiov = {
+		.iov_base = (void *)start,
+		.iov_len = PAGE_SIZE
+	};
+
+	return get_kernel_pages(&kiov, 1, write, pages);
+}
+EXPORT_SYMBOL_GPL(get_kernel_page);
+
+static void pagevec_lru_move_fn(struct pagevec *pvec,
+	void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg),
+	void *arg)
+{
+	int i;
+	struct pglist_data *pgdat = NULL;
+	struct lruvec *lruvec;
+	unsigned long flags = 0;
+
+	for (i = 0; i < pagevec_count(pvec); i++) {
+		struct page *page = pvec->pages[i];
+		struct pglist_data *pagepgdat = page_pgdat(page);
+
+		if (pagepgdat != pgdat) {
+			if (pgdat)
+				spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+			pgdat = pagepgdat;
+			spin_lock_irqsave(&pgdat->lru_lock, flags);
+		}
+
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		(*move_fn)(page, lruvec, arg);
+	}
+	if (pgdat)
+		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	release_pages(pvec->pages, pvec->nr);
+	pagevec_reinit(pvec);
+}
+
+static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec,
+				 void *arg)
+{
+	int *pgmoved = arg;
+
+	if (PageLRU(page) && !PageUnevictable(page)) {
+		del_page_from_lru_list(page, lruvec, page_lru(page));
+		ClearPageActive(page);
+		add_page_to_lru_list_tail(page, lruvec, page_lru(page));
+		(*pgmoved) += thp_nr_pages(page);
+	}
+}
+
+/*
+ * pagevec_move_tail() must be called with IRQ disabled.
+ * Otherwise this may cause nasty races.
+ */
+static void pagevec_move_tail(struct pagevec *pvec)
+{
+	int pgmoved = 0;
+
+	pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved);
+	__count_vm_events(PGROTATED, pgmoved);
+}
+
+/*
+ * Writeback is about to end against a page which has been marked for immediate
+ * reclaim.  If it still appears to be reclaimable, move it to the tail of the
+ * inactive list.
+ */
+void rotate_reclaimable_page(struct page *page)
+{
+	if (!PageLocked(page) && !PageDirty(page) &&
+	    !PageUnevictable(page) && PageLRU(page)) {
+		struct pagevec *pvec;
+		unsigned long flags;
+
+		get_page(page);
+		local_lock_irqsave(&lru_rotate.lock, flags);
+		pvec = this_cpu_ptr(&lru_rotate.pvec);
+		if (!pagevec_add(pvec, page) || PageCompound(page))
+			pagevec_move_tail(pvec);
+		local_unlock_irqrestore(&lru_rotate.lock, flags);
+	}
+}
+
+void lru_note_cost(struct lruvec *lruvec, bool file, unsigned int nr_pages)
+{
+	do {
+		unsigned long lrusize;
+
+		/* Record cost event */
+		if (file)
+			lruvec->file_cost += nr_pages;
+		else
+			lruvec->anon_cost += nr_pages;
+
+		/*
+		 * Decay previous events
+		 *
+		 * Because workloads change over time (and to avoid
+		 * overflow) we keep these statistics as a floating
+		 * average, which ends up weighing recent refaults
+		 * more than old ones.
+		 */
+		lrusize = lruvec_page_state(lruvec, NR_INACTIVE_ANON) +
+			  lruvec_page_state(lruvec, NR_ACTIVE_ANON) +
+			  lruvec_page_state(lruvec, NR_INACTIVE_FILE) +
+			  lruvec_page_state(lruvec, NR_ACTIVE_FILE);
+
+		if (lruvec->file_cost + lruvec->anon_cost > lrusize / 4) {
+			lruvec->file_cost /= 2;
+			lruvec->anon_cost /= 2;
+		}
+	} while ((lruvec = parent_lruvec(lruvec)));
+}
+
+void lru_note_cost_page(struct page *page)
+{
+	lru_note_cost(mem_cgroup_page_lruvec(page, page_pgdat(page)),
+		      page_is_file_lru(page), thp_nr_pages(page));
+}
+
+static void __activate_page(struct page *page, struct lruvec *lruvec,
+			    void *arg)
+{
+	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
+		int lru = page_lru_base_type(page);
+		int nr_pages = thp_nr_pages(page);
+
+		del_page_from_lru_list(page, lruvec, lru);
+		SetPageActive(page);
+		lru += LRU_ACTIVE;
+		add_page_to_lru_list(page, lruvec, lru);
+		trace_mm_lru_activate(page);
+
+		__count_vm_events(PGACTIVATE, nr_pages);
+		__count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE,
+				     nr_pages);
+	}
+}
+
+#ifdef CONFIG_SMP
+static void activate_page_drain(int cpu)
+{
+	struct pagevec *pvec = &per_cpu(lru_pvecs.activate_page, cpu);
+
+	if (pagevec_count(pvec))
+		pagevec_lru_move_fn(pvec, __activate_page, NULL);
+}
+
+static bool need_activate_page_drain(int cpu)
+{
+	return pagevec_count(&per_cpu(lru_pvecs.activate_page, cpu)) != 0;
+}
+
+static void activate_page(struct page *page)
+{
+	page = compound_head(page);
+	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
+		struct pagevec *pvec;
+
+		local_lock(&lru_pvecs.lock);
+		pvec = this_cpu_ptr(&lru_pvecs.activate_page);
+		get_page(page);
+		if (!pagevec_add(pvec, page) || PageCompound(page))
+			pagevec_lru_move_fn(pvec, __activate_page, NULL);
+		local_unlock(&lru_pvecs.lock);
+	}
+}
+
+#else
+static inline void activate_page_drain(int cpu)
+{
+}
+
+static void activate_page(struct page *page)
+{
+	pg_data_t *pgdat = page_pgdat(page);
+
+	page = compound_head(page);
+	spin_lock_irq(&pgdat->lru_lock);
+	__activate_page(page, mem_cgroup_page_lruvec(page, pgdat), NULL);
+	spin_unlock_irq(&pgdat->lru_lock);
+}
+#endif
+
+static void __lru_cache_activate_page(struct page *page)
+{
+	struct pagevec *pvec;
+	int i;
+
+	local_lock(&lru_pvecs.lock);
+	pvec = this_cpu_ptr(&lru_pvecs.lru_add);
+
+	/*
+	 * Search backwards on the optimistic assumption that the page being
+	 * activated has just been added to this pagevec. Note that only
+	 * the local pagevec is examined as a !PageLRU page could be in the
+	 * process of being released, reclaimed, migrated or on a remote
+	 * pagevec that is currently being drained. Furthermore, marking
+	 * a remote pagevec's page PageActive potentially hits a race where
+	 * a page is marked PageActive just after it is added to the inactive
+	 * list causing accounting errors and BUG_ON checks to trigger.
+	 */
+	for (i = pagevec_count(pvec) - 1; i >= 0; i--) {
+		struct page *pagevec_page = pvec->pages[i];
+
+		if (pagevec_page == page) {
+			SetPageActive(page);
+			break;
+		}
+	}
+
+	local_unlock(&lru_pvecs.lock);
+}
+
+/*
+ * Mark a page as having seen activity.
+ *
+ * inactive,unreferenced	->	inactive,referenced
+ * inactive,referenced		->	active,unreferenced
+ * active,unreferenced		->	active,referenced
+ *
+ * When a newly allocated page is not yet visible, so safe for non-atomic ops,
+ * __SetPageReferenced(page) may be substituted for mark_page_accessed(page).
+ */
+void mark_page_accessed(struct page *page)
+{
+	page = compound_head(page);
+
+	if (!PageReferenced(page)) {
+		SetPageReferenced(page);
+	} else if (PageUnevictable(page)) {
+		/*
+		 * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
+		 * this list is never rotated or maintained, so marking an
+		 * evictable page accessed has no effect.
+		 */
+	} else if (!PageActive(page)) {
+		/*
+		 * If the page is on the LRU, queue it for activation via
+		 * lru_pvecs.activate_page. Otherwise, assume the page is on a
+		 * pagevec, mark it active and it'll be moved to the active
+		 * LRU on the next drain.
+		 */
+		if (PageLRU(page))
+			activate_page(page);
+		else
+			__lru_cache_activate_page(page);
+		ClearPageReferenced(page);
+		workingset_activation(page);
+	}
+	if (page_is_idle(page))
+		clear_page_idle(page);
+}
+EXPORT_SYMBOL(mark_page_accessed);
+
+/**
+ * lru_cache_add - add a page to a page list
+ * @page: the page to be added to the LRU.
+ *
+ * Queue the page for addition to the LRU via pagevec. The decision on whether
+ * to add the page to the [in]active [file|anon] list is deferred until the
+ * pagevec is drained. This gives a chance for the caller of lru_cache_add()
+ * have the page added to the active list using mark_page_accessed().
+ */
+void lru_cache_add(struct page *page)
+{
+	struct pagevec *pvec;
+
+	VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
+	VM_BUG_ON_PAGE(PageLRU(page), page);
+
+	get_page(page);
+	local_lock(&lru_pvecs.lock);
+	pvec = this_cpu_ptr(&lru_pvecs.lru_add);
+	if (!pagevec_add(pvec, page) || PageCompound(page))
+		__pagevec_lru_add(pvec);
+	local_unlock(&lru_pvecs.lock);
+}
+EXPORT_SYMBOL(lru_cache_add);
+
+/**
+ * lru_cache_add_inactive_or_unevictable
+ * @page:  the page to be added to LRU
+ * @vma:   vma in which page is mapped for determining reclaimability
+ *
+ * Place @page on the inactive or unevictable LRU list, depending on its
+ * evictability.
+ */
+void lru_cache_add_inactive_or_unevictable(struct page *page,
+					 struct vm_area_struct *vma)
+{
+	bool unevictable;
+
+	VM_BUG_ON_PAGE(PageLRU(page), page);
+
+	unevictable = (vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) == VM_LOCKED;
+	if (unlikely(unevictable) && !TestSetPageMlocked(page)) {
+		int nr_pages = thp_nr_pages(page);
+		/*
+		 * We use the irq-unsafe __mod_zone_page_stat because this
+		 * counter is not modified from interrupt context, and the pte
+		 * lock is held(spinlock), which implies preemption disabled.
+		 */
+		__mod_zone_page_state(page_zone(page), NR_MLOCK, nr_pages);
+		count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
+	}
+	lru_cache_add(page);
+}
+
+/*
+ * If the page can not be invalidated, it is moved to the
+ * inactive list to speed up its reclaim.  It is moved to the
+ * head of the list, rather than the tail, to give the flusher
+ * threads some time to write it out, as this is much more
+ * effective than the single-page writeout from reclaim.
+ *
+ * If the page isn't page_mapped and dirty/writeback, the page
+ * could reclaim asap using PG_reclaim.
+ *
+ * 1. active, mapped page -> none
+ * 2. active, dirty/writeback page -> inactive, head, PG_reclaim
+ * 3. inactive, mapped page -> none
+ * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim
+ * 5. inactive, clean -> inactive, tail
+ * 6. Others -> none
+ *
+ * In 4, why it moves inactive's head, the VM expects the page would
+ * be write it out by flusher threads as this is much more effective
+ * than the single-page writeout from reclaim.
+ */
+static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
+			      void *arg)
+{
+	int lru;
+	bool active;
+	int nr_pages = thp_nr_pages(page);
+
+	if (!PageLRU(page))
+		return;
+
+	if (PageUnevictable(page))
+		return;
+
+	/* Some processes are using the page */
+	if (page_mapped(page))
+		return;
+
+	active = PageActive(page);
+	lru = page_lru_base_type(page);
+
+	del_page_from_lru_list(page, lruvec, lru + active);
+	ClearPageActive(page);
+	ClearPageReferenced(page);
+
+	if (PageWriteback(page) || PageDirty(page)) {
+		/*
+		 * PG_reclaim could be raced with end_page_writeback
+		 * It can make readahead confusing.  But race window
+		 * is _really_ small and  it's non-critical problem.
+		 */
+		add_page_to_lru_list(page, lruvec, lru);
+		SetPageReclaim(page);
+	} else {
+		/*
+		 * The page's writeback ends up during pagevec
+		 * We moves tha page into tail of inactive.
+		 */
+		add_page_to_lru_list_tail(page, lruvec, lru);
+		__count_vm_events(PGROTATED, nr_pages);
+	}
+
+	if (active) {
+		__count_vm_events(PGDEACTIVATE, nr_pages);
+		__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
+				     nr_pages);
+	}
+}
+
+static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
+			    void *arg)
+{
+	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
+		int lru = page_lru_base_type(page);
+		int nr_pages = thp_nr_pages(page);
+
+		del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE);
+		ClearPageActive(page);
+		ClearPageReferenced(page);
+		add_page_to_lru_list(page, lruvec, lru);
+
+		__count_vm_events(PGDEACTIVATE, nr_pages);
+		__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
+				     nr_pages);
+	}
+}
+
+static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
+			    void *arg)
+{
+	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
+	    !PageSwapCache(page) && !PageUnevictable(page)) {
+		bool active = PageActive(page);
+		int nr_pages = thp_nr_pages(page);
+
+		del_page_from_lru_list(page, lruvec,
+				       LRU_INACTIVE_ANON + active);
+		ClearPageActive(page);
+		ClearPageReferenced(page);
+		/*
+		 * Lazyfree pages are clean anonymous pages.  They have
+		 * PG_swapbacked flag cleared, to distinguish them from normal
+		 * anonymous pages
+		 */
+		ClearPageSwapBacked(page);
+		add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE);
+
+		__count_vm_events(PGLAZYFREE, nr_pages);
+		__count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE,
+				     nr_pages);
+	}
+}
+
+/*
+ * Drain pages out of the cpu's pagevecs.
+ * Either "cpu" is the current CPU, and preemption has already been
+ * disabled; or "cpu" is being hot-unplugged, and is already dead.
+ */
+void lru_add_drain_cpu(int cpu)
+{
+	struct pagevec *pvec = &per_cpu(lru_pvecs.lru_add, cpu);
+
+	if (pagevec_count(pvec))
+		__pagevec_lru_add(pvec);
+
+	pvec = &per_cpu(lru_rotate.pvec, cpu);
+	/* Disabling interrupts below acts as a compiler barrier. */
+	if (data_race(pagevec_count(pvec))) {
+		unsigned long flags;
+
+		/* No harm done if a racing interrupt already did this */
+		local_lock_irqsave(&lru_rotate.lock, flags);
+		pagevec_move_tail(pvec);
+		local_unlock_irqrestore(&lru_rotate.lock, flags);
+	}
+
+	pvec = &per_cpu(lru_pvecs.lru_deactivate_file, cpu);
+	if (pagevec_count(pvec))
+		pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);
+
+	pvec = &per_cpu(lru_pvecs.lru_deactivate, cpu);
+	if (pagevec_count(pvec))
+		pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
+
+	pvec = &per_cpu(lru_pvecs.lru_lazyfree, cpu);
+	if (pagevec_count(pvec))
+		pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);
+
+	activate_page_drain(cpu);
+}
+
+/**
+ * deactivate_file_page - forcefully deactivate a file page
+ * @page: page to deactivate
+ *
+ * This function hints the VM that @page is a good reclaim candidate,
+ * for example if its invalidation fails due to the page being dirty
+ * or under writeback.
+ */
+void deactivate_file_page(struct page *page)
+{
+	/*
+	 * In a workload with many unevictable page such as mprotect,
+	 * unevictable page deactivation for accelerating reclaim is pointless.
+	 */
+	if (PageUnevictable(page))
+		return;
+
+	if (likely(get_page_unless_zero(page))) {
+		struct pagevec *pvec;
+
+		local_lock(&lru_pvecs.lock);
+		pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate_file);
+
+		if (!pagevec_add(pvec, page) || PageCompound(page))
+			pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);
+		local_unlock(&lru_pvecs.lock);
+	}
+}
+
+/*
+ * deactivate_page - deactivate a page
+ * @page: page to deactivate
+ *
+ * deactivate_page() moves @page to the inactive list if @page was on the active
+ * list and was not an unevictable page.  This is done to accelerate the reclaim
+ * of @page.
+ */
+void deactivate_page(struct page *page)
+{
+	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
+		struct pagevec *pvec;
+
+		local_lock(&lru_pvecs.lock);
+		pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate);
+		get_page(page);
+		if (!pagevec_add(pvec, page) || PageCompound(page))
+			pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
+		local_unlock(&lru_pvecs.lock);
+	}
+}
+
+/**
+ * mark_page_lazyfree - make an anon page lazyfree
+ * @page: page to deactivate
+ *
+ * mark_page_lazyfree() moves @page to the inactive file list.
+ * This is done to accelerate the reclaim of @page.
+ */
+void mark_page_lazyfree(struct page *page)
+{
+	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
+	    !PageSwapCache(page) && !PageUnevictable(page)) {
+		struct pagevec *pvec;
+
+		local_lock(&lru_pvecs.lock);
+		pvec = this_cpu_ptr(&lru_pvecs.lru_lazyfree);
+		get_page(page);
+		if (!pagevec_add(pvec, page) || PageCompound(page))
+			pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);
+		local_unlock(&lru_pvecs.lock);
+	}
+}
+
+void lru_add_drain(void)
+{
+	local_lock(&lru_pvecs.lock);
+	lru_add_drain_cpu(smp_processor_id());
+	local_unlock(&lru_pvecs.lock);
+}
+
+void lru_add_drain_cpu_zone(struct zone *zone)
+{
+	local_lock(&lru_pvecs.lock);
+	lru_add_drain_cpu(smp_processor_id());
+	drain_local_pages(zone);
+	local_unlock(&lru_pvecs.lock);
+}
+
+#ifdef CONFIG_SMP
+
+static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
+
+static void lru_add_drain_per_cpu(struct work_struct *dummy)
+{
+	lru_add_drain();
+}
+
+/*
+ * Doesn't need any cpu hotplug locking because we do rely on per-cpu
+ * kworkers being shut down before our page_alloc_cpu_dead callback is
+ * executed on the offlined cpu.
+ * Calling this function with cpu hotplug locks held can actually lead
+ * to obscure indirect dependencies via WQ context.
+ */
+void lru_add_drain_all(void)
+{
+	/*
+	 * lru_drain_gen - Global pages generation number
+	 *
+	 * (A) Definition: global lru_drain_gen = x implies that all generations
+	 *     0 < n <= x are already *scheduled* for draining.
+	 *
+	 * This is an optimization for the highly-contended use case where a
+	 * user space workload keeps constantly generating a flow of pages for
+	 * each CPU.
+	 */
+	static unsigned int lru_drain_gen;
+	static struct cpumask has_work;
+	static DEFINE_MUTEX(lock);
+	unsigned cpu, this_gen;
+
+	/*
+	 * Make sure nobody triggers this path before mm_percpu_wq is fully
+	 * initialized.
+	 */
+	if (WARN_ON(!mm_percpu_wq))
+		return;
+
+	/*
+	 * Guarantee pagevec counter stores visible by this CPU are visible to
+	 * other CPUs before loading the current drain generation.
+	 */
+	smp_mb();
+
+	/*
+	 * (B) Locally cache global LRU draining generation number
+	 *
+	 * The read barrier ensures that the counter is loaded before the mutex
+	 * is taken. It pairs with smp_mb() inside the mutex critical section
+	 * at (D).
+	 */
+	this_gen = smp_load_acquire(&lru_drain_gen);
+
+	mutex_lock(&lock);
+
+	/*
+	 * (C) Exit the draining operation if a newer generation, from another
+	 * lru_add_drain_all(), was already scheduled for draining. Check (A).
+	 */
+	if (unlikely(this_gen != lru_drain_gen))
+		goto done;
+
+	/*
+	 * (D) Increment global generation number
+	 *
+	 * Pairs with smp_load_acquire() at (B), outside of the critical
+	 * section. Use a full memory barrier to guarantee that the new global
+	 * drain generation number is stored before loading pagevec counters.
+	 *
+	 * This pairing must be done here, before the for_each_online_cpu loop
+	 * below which drains the page vectors.
+	 *
+	 * Let x, y, and z represent some system CPU numbers, where x < y < z.
+	 * Assume CPU #z is is in the middle of the for_each_online_cpu loop
+	 * below and has already reached CPU #y's per-cpu data. CPU #x comes
+	 * along, adds some pages to its per-cpu vectors, then calls
+	 * lru_add_drain_all().
+	 *
+	 * If the paired barrier is done at any later step, e.g. after the
+	 * loop, CPU #x will just exit at (C) and miss flushing out all of its
+	 * added pages.
+	 */
+	WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1);
+	smp_mb();
+
+	cpumask_clear(&has_work);
+	for_each_online_cpu(cpu) {
+		struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
+
+		if (pagevec_count(&per_cpu(lru_pvecs.lru_add, cpu)) ||
+		    data_race(pagevec_count(&per_cpu(lru_rotate.pvec, cpu))) ||
+		    pagevec_count(&per_cpu(lru_pvecs.lru_deactivate_file, cpu)) ||
+		    pagevec_count(&per_cpu(lru_pvecs.lru_deactivate, cpu)) ||
+		    pagevec_count(&per_cpu(lru_pvecs.lru_lazyfree, cpu)) ||
+		    need_activate_page_drain(cpu)) {
+			INIT_WORK(work, lru_add_drain_per_cpu);
+			queue_work_on(cpu, mm_percpu_wq, work);
+			__cpumask_set_cpu(cpu, &has_work);
+		}
+	}
+
+	for_each_cpu(cpu, &has_work)
+		flush_work(&per_cpu(lru_add_drain_work, cpu));
+
+done:
+	mutex_unlock(&lock);
+}
+#else
+void lru_add_drain_all(void)
+{
+	lru_add_drain();
+}
+#endif /* CONFIG_SMP */
+
+/**
+ * release_pages - batched put_page()
+ * @pages: array of pages to release
+ * @nr: number of pages
+ *
+ * Decrement the reference count on all the pages in @pages.  If it
+ * fell to zero, remove the page from the LRU and free it.
+ */
+void release_pages(struct page **pages, int nr)
+{
+	int i;
+	LIST_HEAD(pages_to_free);
+	struct pglist_data *locked_pgdat = NULL;
+	struct lruvec *lruvec;
+	unsigned long flags;
+	unsigned int lock_batch;
+
+	for (i = 0; i < nr; i++) {
+		struct page *page = pages[i];
+
+		/*
+		 * Make sure the IRQ-safe lock-holding time does not get
+		 * excessive with a continuous string of pages from the
+		 * same pgdat. The lock is held only if pgdat != NULL.
+		 */
+		if (locked_pgdat && ++lock_batch == SWAP_CLUSTER_MAX) {
+			spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
+			locked_pgdat = NULL;
+		}
+
+		page = compound_head(page);
+		if (is_huge_zero_page(page))
+			continue;
+
+		if (is_zone_device_page(page)) {
+			if (locked_pgdat) {
+				spin_unlock_irqrestore(&locked_pgdat->lru_lock,
+						       flags);
+				locked_pgdat = NULL;
+			}
+			/*
+			 * ZONE_DEVICE pages that return 'false' from
+			 * page_is_devmap_managed() do not require special
+			 * processing, and instead, expect a call to
+			 * put_page_testzero().
+			 */
+			if (page_is_devmap_managed(page)) {
+				put_devmap_managed_page(page);
+				continue;
+			}
+		}
+
+		if (!put_page_testzero(page))
+			continue;
+
+		if (PageCompound(page)) {
+			if (locked_pgdat) {
+				spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
+				locked_pgdat = NULL;
+			}
+			__put_compound_page(page);
+			continue;
+		}
+
+		if (PageLRU(page)) {
+			struct pglist_data *pgdat = page_pgdat(page);
+
+			if (pgdat != locked_pgdat) {
+				if (locked_pgdat)
+					spin_unlock_irqrestore(&locked_pgdat->lru_lock,
+									flags);
+				lock_batch = 0;
+				locked_pgdat = pgdat;
+				spin_lock_irqsave(&locked_pgdat->lru_lock, flags);
+			}
+
+			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
+			VM_BUG_ON_PAGE(!PageLRU(page), page);
+			__ClearPageLRU(page);
+			del_page_from_lru_list(page, lruvec, page_off_lru(page));
+		}
+
+		__ClearPageWaiters(page);
+
+		list_add(&page->lru, &pages_to_free);
+	}
+	if (locked_pgdat)
+		spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
+
+	mem_cgroup_uncharge_list(&pages_to_free);
+	free_unref_page_list(&pages_to_free);
+}
+EXPORT_SYMBOL(release_pages);
+
+/*
+ * The pages which we're about to release may be in the deferred lru-addition
+ * queues.  That would prevent them from really being freed right now.  That's
+ * OK from a correctness point of view but is inefficient - those pages may be
+ * cache-warm and we want to give them back to the page allocator ASAP.
+ *
+ * So __pagevec_release() will drain those queues here.  __pagevec_lru_add()
+ * and __pagevec_lru_add_active() call release_pages() directly to avoid
+ * mutual recursion.
+ */
+void __pagevec_release(struct pagevec *pvec)
+{
+	if (!pvec->percpu_pvec_drained) {
+		lru_add_drain();
+		pvec->percpu_pvec_drained = true;
+	}
+	release_pages(pvec->pages, pagevec_count(pvec));
+	pagevec_reinit(pvec);
+}
+EXPORT_SYMBOL(__pagevec_release);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/* used by __split_huge_page_refcount() */
+void lru_add_page_tail(struct page *page, struct page *page_tail,
+		       struct lruvec *lruvec, struct list_head *list)
+{
+	VM_BUG_ON_PAGE(!PageHead(page), page);
+	VM_BUG_ON_PAGE(PageCompound(page_tail), page);
+	VM_BUG_ON_PAGE(PageLRU(page_tail), page);
+	lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
+
+	if (!list)
+		SetPageLRU(page_tail);
+
+	if (likely(PageLRU(page)))
+		list_add_tail(&page_tail->lru, &page->lru);
+	else if (list) {
+		/* page reclaim is reclaiming a huge page */
+		get_page(page_tail);
+		list_add_tail(&page_tail->lru, list);
+	} else {
+		/*
+		 * Head page has not yet been counted, as an hpage,
+		 * so we must account for each subpage individually.
+		 *
+		 * Put page_tail on the list at the correct position
+		 * so they all end up in order.
+		 */
+		add_page_to_lru_list_tail(page_tail, lruvec,
+					  page_lru(page_tail));
+	}
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
+				 void *arg)
+{
+	enum lru_list lru;
+	int was_unevictable = TestClearPageUnevictable(page);
+	int nr_pages = thp_nr_pages(page);
+
+	VM_BUG_ON_PAGE(PageLRU(page), page);
+
+	/*
+	 * Page becomes evictable in two ways:
+	 * 1) Within LRU lock [munlock_vma_page() and __munlock_pagevec()].
+	 * 2) Before acquiring LRU lock to put the page to correct LRU and then
+	 *   a) do PageLRU check with lock [check_move_unevictable_pages]
+	 *   b) do PageLRU check before lock [clear_page_mlock]
+	 *
+	 * (1) & (2a) are ok as LRU lock will serialize them. For (2b), we need
+	 * following strict ordering:
+	 *
+	 * #0: __pagevec_lru_add_fn		#1: clear_page_mlock
+	 *
+	 * SetPageLRU()				TestClearPageMlocked()
+	 * smp_mb() // explicit ordering	// above provides strict
+	 *					// ordering
+	 * PageMlocked()			PageLRU()
+	 *
+	 *
+	 * if '#1' does not observe setting of PG_lru by '#0' and fails
+	 * isolation, the explicit barrier will make sure that page_evictable
+	 * check will put the page in correct LRU. Without smp_mb(), SetPageLRU
+	 * can be reordered after PageMlocked check and can make '#1' to fail
+	 * the isolation of the page whose Mlocked bit is cleared (#0 is also
+	 * looking at the same page) and the evictable page will be stranded
+	 * in an unevictable LRU.
+	 */
+	SetPageLRU(page);
+	smp_mb__after_atomic();
+
+	if (page_evictable(page)) {
+		lru = page_lru(page);
+		if (was_unevictable)
+			__count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
+	} else {
+		lru = LRU_UNEVICTABLE;
+		ClearPageActive(page);
+		SetPageUnevictable(page);
+		if (!was_unevictable)
+			__count_vm_events(UNEVICTABLE_PGCULLED, nr_pages);
+	}
+
+	add_page_to_lru_list(page, lruvec, lru);
+	trace_mm_lru_insertion(page, lru);
+}
+
+/*
+ * Add the passed pages to the LRU, then drop the caller's refcount
+ * on them.  Reinitialises the caller's pagevec.
+ */
+void __pagevec_lru_add(struct pagevec *pvec)
+{
+	pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, NULL);
+}
+
+/**
+ * pagevec_lookup_entries - gang pagecache lookup
+ * @pvec:	Where the resulting entries are placed
+ * @mapping:	The address_space to search
+ * @start:	The starting entry index
+ * @nr_entries:	The maximum number of pages
+ * @indices:	The cache indices corresponding to the entries in @pvec
+ *
+ * pagevec_lookup_entries() will search for and return a group of up
+ * to @nr_pages pages and shadow entries in the mapping.  All
+ * entries are placed in @pvec.  pagevec_lookup_entries() takes a
+ * reference against actual pages in @pvec.
+ *
+ * The search returns a group of mapping-contiguous entries with
+ * ascending indexes.  There may be holes in the indices due to
+ * not-present entries.
+ *
+ * Only one subpage of a Transparent Huge Page is returned in one call:
+ * allowing truncate_inode_pages_range() to evict the whole THP without
+ * cycling through a pagevec of extra references.
+ *
+ * pagevec_lookup_entries() returns the number of entries which were
+ * found.
+ */
+unsigned pagevec_lookup_entries(struct pagevec *pvec,
+				struct address_space *mapping,
+				pgoff_t start, unsigned nr_entries,
+				pgoff_t *indices)
+{
+	pvec->nr = find_get_entries(mapping, start, nr_entries,
+				    pvec->pages, indices);
+	return pagevec_count(pvec);
+}
+
+/**
+ * pagevec_remove_exceptionals - pagevec exceptionals pruning
+ * @pvec:	The pagevec to prune
+ *
+ * pagevec_lookup_entries() fills both pages and exceptional radix
+ * tree entries into the pagevec.  This function prunes all
+ * exceptionals from @pvec without leaving holes, so that it can be
+ * passed on to page-only pagevec operations.
+ */
+void pagevec_remove_exceptionals(struct pagevec *pvec)
+{
+	int i, j;
+
+	for (i = 0, j = 0; i < pagevec_count(pvec); i++) {
+		struct page *page = pvec->pages[i];
+		if (!xa_is_value(page))
+			pvec->pages[j++] = page;
+	}
+	pvec->nr = j;
+}
+
+/**
+ * pagevec_lookup_range - gang pagecache lookup
+ * @pvec:	Where the resulting pages are placed
+ * @mapping:	The address_space to search
+ * @start:	The starting page index
+ * @end:	The final page index
+ *
+ * pagevec_lookup_range() will search for & return a group of up to PAGEVEC_SIZE
+ * pages in the mapping starting from index @start and upto index @end
+ * (inclusive).  The pages are placed in @pvec.  pagevec_lookup() takes a
+ * reference against the pages in @pvec.
+ *
+ * The search returns a group of mapping-contiguous pages with ascending
+ * indexes.  There may be holes in the indices due to not-present pages. We
+ * also update @start to index the next page for the traversal.
+ *
+ * pagevec_lookup_range() returns the number of pages which were found. If this
+ * number is smaller than PAGEVEC_SIZE, the end of specified range has been
+ * reached.
+ */
+unsigned pagevec_lookup_range(struct pagevec *pvec,
+		struct address_space *mapping, pgoff_t *start, pgoff_t end)
+{
+	pvec->nr = find_get_pages_range(mapping, start, end, PAGEVEC_SIZE,
+					pvec->pages);
+	return pagevec_count(pvec);
+}
+EXPORT_SYMBOL(pagevec_lookup_range);
+
+unsigned pagevec_lookup_range_tag(struct pagevec *pvec,
+		struct address_space *mapping, pgoff_t *index, pgoff_t end,
+		xa_mark_t tag)
+{
+	pvec->nr = find_get_pages_range_tag(mapping, index, end, tag,
+					PAGEVEC_SIZE, pvec->pages);
+	return pagevec_count(pvec);
+}
+EXPORT_SYMBOL(pagevec_lookup_range_tag);
+
+unsigned pagevec_lookup_range_nr_tag(struct pagevec *pvec,
+		struct address_space *mapping, pgoff_t *index, pgoff_t end,
+		xa_mark_t tag, unsigned max_pages)
+{
+	pvec->nr = find_get_pages_range_tag(mapping, index, end, tag,
+		min_t(unsigned int, max_pages, PAGEVEC_SIZE), pvec->pages);
+	return pagevec_count(pvec);
+}
+EXPORT_SYMBOL(pagevec_lookup_range_nr_tag);
+/*
+ * Perform any setup for the swap system
+ */
+void __init swap_setup(void)
+{
+	unsigned long megs = totalram_pages() >> (20 - PAGE_SHIFT);
+
+	/* Use a smaller cluster for small-memory machines */
+	if (megs < 16)
+		page_cluster = 2;
+	else
+		page_cluster = 3;
+	/*
+	 * Right now other parts of the system means that we
+	 * _really_ don't want to cluster much more
+	 */
+}
+
+#ifdef CONFIG_DEV_PAGEMAP_OPS
+void put_devmap_managed_page(struct page *page)
+{
+	int count;
+
+	if (WARN_ON_ONCE(!page_is_devmap_managed(page)))
+		return;
+
+	count = page_ref_dec_return(page);
+
+	/*
+	 * devmap page refcounts are 1-based, rather than 0-based: if
+	 * refcount is 1, then the page is free and the refcount is
+	 * stable because nobody holds a reference on the page.
+	 */
+	if (count == 1)
+		free_devmap_managed_page(page);
+	else if (!count)
+		__put_page(page);
+}
+EXPORT_SYMBOL(put_devmap_managed_page);
+#endif