Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 2277 insertions, 0 deletions

diff --git a/mm/vmstat.c b/mm/vmstat.c
new file mode 100644
index 0000000000..00e81e99c6
--- /dev/null
+++ b/mm/vmstat.c
@@ -0,0 +1,2277 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/mm/vmstat.c
+ *
+ *  Manages VM statistics
+ *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ *
+ *  zoned VM statistics
+ *  Copyright (C) 2006 Silicon Graphics, Inc.,
+ *		Christoph Lameter <christoph@lameter.com>
+ *  Copyright (C) 2008-2014 Christoph Lameter
+ */
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/vmstat.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/sched.h>
+#include <linux/math64.h>
+#include <linux/writeback.h>
+#include <linux/compaction.h>
+#include <linux/mm_inline.h>
+#include <linux/page_owner.h>
+#include <linux/sched/isolation.h>
+
+#include "internal.h"
+
+#ifdef CONFIG_NUMA
+int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
+
+/* zero numa counters within a zone */
+static void zero_zone_numa_counters(struct zone *zone)
+{
+	int item, cpu;
+
+	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++) {
+		atomic_long_set(&zone->vm_numa_event[item], 0);
+		for_each_online_cpu(cpu) {
+			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_event[item]
+						= 0;
+		}
+	}
+}
+
+/* zero numa counters of all the populated zones */
+static void zero_zones_numa_counters(void)
+{
+	struct zone *zone;
+
+	for_each_populated_zone(zone)
+		zero_zone_numa_counters(zone);
+}
+
+/* zero global numa counters */
+static void zero_global_numa_counters(void)
+{
+	int item;
+
+	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
+		atomic_long_set(&vm_numa_event[item], 0);
+}
+
+static void invalid_numa_statistics(void)
+{
+	zero_zones_numa_counters();
+	zero_global_numa_counters();
+}
+
+static DEFINE_MUTEX(vm_numa_stat_lock);
+
+int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *length, loff_t *ppos)
+{
+	int ret, oldval;
+
+	mutex_lock(&vm_numa_stat_lock);
+	if (write)
+		oldval = sysctl_vm_numa_stat;
+	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
+	if (ret || !write)
+		goto out;
+
+	if (oldval == sysctl_vm_numa_stat)
+		goto out;
+	else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
+		static_branch_enable(&vm_numa_stat_key);
+		pr_info("enable numa statistics\n");
+	} else {
+		static_branch_disable(&vm_numa_stat_key);
+		invalid_numa_statistics();
+		pr_info("disable numa statistics, and clear numa counters\n");
+	}
+
+out:
+	mutex_unlock(&vm_numa_stat_lock);
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_VM_EVENT_COUNTERS
+DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
+EXPORT_PER_CPU_SYMBOL(vm_event_states);
+
+static void sum_vm_events(unsigned long *ret)
+{
+	int cpu;
+	int i;
+
+	memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
+
+	for_each_online_cpu(cpu) {
+		struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
+
+		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+			ret[i] += this->event[i];
+	}
+}
+
+/*
+ * Accumulate the vm event counters across all CPUs.
+ * The result is unavoidably approximate - it can change
+ * during and after execution of this function.
+*/
+void all_vm_events(unsigned long *ret)
+{
+	cpus_read_lock();
+	sum_vm_events(ret);
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(all_vm_events);
+
+/*
+ * Fold the foreign cpu events into our own.
+ *
+ * This is adding to the events on one processor
+ * but keeps the global counts constant.
+ */
+void vm_events_fold_cpu(int cpu)
+{
+	struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
+	int i;
+
+	for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
+		count_vm_events(i, fold_state->event[i]);
+		fold_state->event[i] = 0;
+	}
+}
+
+#endif /* CONFIG_VM_EVENT_COUNTERS */
+
+/*
+ * Manage combined zone based / global counters
+ *
+ * vm_stat contains the global counters
+ */
+atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
+atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
+atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS] __cacheline_aligned_in_smp;
+EXPORT_SYMBOL(vm_zone_stat);
+EXPORT_SYMBOL(vm_node_stat);
+
+#ifdef CONFIG_NUMA
+static void fold_vm_zone_numa_events(struct zone *zone)
+{
+	unsigned long zone_numa_events[NR_VM_NUMA_EVENT_ITEMS] = { 0, };
+	int cpu;
+	enum numa_stat_item item;
+
+	for_each_online_cpu(cpu) {
+		struct per_cpu_zonestat *pzstats;
+
+		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
+		for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
+			zone_numa_events[item] += xchg(&pzstats->vm_numa_event[item], 0);
+	}
+
+	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
+		zone_numa_event_add(zone_numa_events[item], zone, item);
+}
+
+void fold_vm_numa_events(void)
+{
+	struct zone *zone;
+
+	for_each_populated_zone(zone)
+		fold_vm_zone_numa_events(zone);
+}
+#endif
+
+#ifdef CONFIG_SMP
+
+int calculate_pressure_threshold(struct zone *zone)
+{
+	int threshold;
+	int watermark_distance;
+
+	/*
+	 * As vmstats are not up to date, there is drift between the estimated
+	 * and real values. For high thresholds and a high number of CPUs, it
+	 * is possible for the min watermark to be breached while the estimated
+	 * value looks fine. The pressure threshold is a reduced value such
+	 * that even the maximum amount of drift will not accidentally breach
+	 * the min watermark
+	 */
+	watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
+	threshold = max(1, (int)(watermark_distance / num_online_cpus()));
+
+	/*
+	 * Maximum threshold is 125
+	 */
+	threshold = min(125, threshold);
+
+	return threshold;
+}
+
+int calculate_normal_threshold(struct zone *zone)
+{
+	int threshold;
+	int mem;	/* memory in 128 MB units */
+
+	/*
+	 * The threshold scales with the number of processors and the amount
+	 * of memory per zone. More memory means that we can defer updates for
+	 * longer, more processors could lead to more contention.
+ 	 * fls() is used to have a cheap way of logarithmic scaling.
+	 *
+	 * Some sample thresholds:
+	 *
+	 * Threshold	Processors	(fls)	Zonesize	fls(mem)+1
+	 * ------------------------------------------------------------------
+	 * 8		1		1	0.9-1 GB	4
+	 * 16		2		2	0.9-1 GB	4
+	 * 20 		2		2	1-2 GB		5
+	 * 24		2		2	2-4 GB		6
+	 * 28		2		2	4-8 GB		7
+	 * 32		2		2	8-16 GB		8
+	 * 4		2		2	<128M		1
+	 * 30		4		3	2-4 GB		5
+	 * 48		4		3	8-16 GB		8
+	 * 32		8		4	1-2 GB		4
+	 * 32		8		4	0.9-1GB		4
+	 * 10		16		5	<128M		1
+	 * 40		16		5	900M		4
+	 * 70		64		7	2-4 GB		5
+	 * 84		64		7	4-8 GB		6
+	 * 108		512		9	4-8 GB		6
+	 * 125		1024		10	8-16 GB		8
+	 * 125		1024		10	16-32 GB	9
+	 */
+
+	mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
+
+	threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
+
+	/*
+	 * Maximum threshold is 125
+	 */
+	threshold = min(125, threshold);
+
+	return threshold;
+}
+
+/*
+ * Refresh the thresholds for each zone.
+ */
+void refresh_zone_stat_thresholds(void)
+{
+	struct pglist_data *pgdat;
+	struct zone *zone;
+	int cpu;
+	int threshold;
+
+	/* Zero current pgdat thresholds */
+	for_each_online_pgdat(pgdat) {
+		for_each_online_cpu(cpu) {
+			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
+		}
+	}
+
+	for_each_populated_zone(zone) {
+		struct pglist_data *pgdat = zone->zone_pgdat;
+		unsigned long max_drift, tolerate_drift;
+
+		threshold = calculate_normal_threshold(zone);
+
+		for_each_online_cpu(cpu) {
+			int pgdat_threshold;
+
+			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
+							= threshold;
+
+			/* Base nodestat threshold on the largest populated zone. */
+			pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
+			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
+				= max(threshold, pgdat_threshold);
+		}
+
+		/*
+		 * Only set percpu_drift_mark if there is a danger that
+		 * NR_FREE_PAGES reports the low watermark is ok when in fact
+		 * the min watermark could be breached by an allocation
+		 */
+		tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
+		max_drift = num_online_cpus() * threshold;
+		if (max_drift > tolerate_drift)
+			zone->percpu_drift_mark = high_wmark_pages(zone) +
+					max_drift;
+	}
+}
+
+void set_pgdat_percpu_threshold(pg_data_t *pgdat,
+				int (*calculate_pressure)(struct zone *))
+{
+	struct zone *zone;
+	int cpu;
+	int threshold;
+	int i;
+
+	for (i = 0; i < pgdat->nr_zones; i++) {
+		zone = &pgdat->node_zones[i];
+		if (!zone->percpu_drift_mark)
+			continue;
+
+		threshold = (*calculate_pressure)(zone);
+		for_each_online_cpu(cpu)
+			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
+							= threshold;
+	}
+}
+
+/*
+ * For use when we know that interrupts are disabled,
+ * or when we know that preemption is disabled and that
+ * particular counter cannot be updated from interrupt context.
+ */
+void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
+			   long delta)
+{
+	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
+	s8 __percpu *p = pcp->vm_stat_diff + item;
+	long x;
+	long t;
+
+	/*
+	 * Accurate vmstat updates require a RMW. On !PREEMPT_RT kernels,
+	 * atomicity is provided by IRQs being disabled -- either explicitly
+	 * or via local_lock_irq. On PREEMPT_RT, local_lock_irq only disables
+	 * CPU migrations and preemption potentially corrupts a counter so
+	 * disable preemption.
+	 */
+	preempt_disable_nested();
+
+	x = delta + __this_cpu_read(*p);
+
+	t = __this_cpu_read(pcp->stat_threshold);
+
+	if (unlikely(abs(x) > t)) {
+		zone_page_state_add(x, zone, item);
+		x = 0;
+	}
+	__this_cpu_write(*p, x);
+
+	preempt_enable_nested();
+}
+EXPORT_SYMBOL(__mod_zone_page_state);
+
+void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+				long delta)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	long x;
+	long t;
+
+	if (vmstat_item_in_bytes(item)) {
+		/*
+		 * Only cgroups use subpage accounting right now; at
+		 * the global level, these items still change in
+		 * multiples of whole pages. Store them as pages
+		 * internally to keep the per-cpu counters compact.
+		 */
+		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
+		delta >>= PAGE_SHIFT;
+	}
+
+	/* See __mod_node_page_state */
+	preempt_disable_nested();
+
+	x = delta + __this_cpu_read(*p);
+
+	t = __this_cpu_read(pcp->stat_threshold);
+
+	if (unlikely(abs(x) > t)) {
+		node_page_state_add(x, pgdat, item);
+		x = 0;
+	}
+	__this_cpu_write(*p, x);
+
+	preempt_enable_nested();
+}
+EXPORT_SYMBOL(__mod_node_page_state);
+
+/*
+ * Optimized increment and decrement functions.
+ *
+ * These are only for a single page and therefore can take a struct page *
+ * argument instead of struct zone *. This allows the inclusion of the code
+ * generated for page_zone(page) into the optimized functions.
+ *
+ * No overflow check is necessary and therefore the differential can be
+ * incremented or decremented in place which may allow the compilers to
+ * generate better code.
+ * The increment or decrement is known and therefore one boundary check can
+ * be omitted.
+ *
+ * NOTE: These functions are very performance sensitive. Change only
+ * with care.
+ *
+ * Some processors have inc/dec instructions that are atomic vs an interrupt.
+ * However, the code must first determine the differential location in a zone
+ * based on the processor number and then inc/dec the counter. There is no
+ * guarantee without disabling preemption that the processor will not change
+ * in between and therefore the atomicity vs. interrupt cannot be exploited
+ * in a useful way here.
+ */
+void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
+{
+	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
+	s8 __percpu *p = pcp->vm_stat_diff + item;
+	s8 v, t;
+
+	/* See __mod_node_page_state */
+	preempt_disable_nested();
+
+	v = __this_cpu_inc_return(*p);
+	t = __this_cpu_read(pcp->stat_threshold);
+	if (unlikely(v > t)) {
+		s8 overstep = t >> 1;
+
+		zone_page_state_add(v + overstep, zone, item);
+		__this_cpu_write(*p, -overstep);
+	}
+
+	preempt_enable_nested();
+}
+
+void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	s8 v, t;
+
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
+	/* See __mod_node_page_state */
+	preempt_disable_nested();
+
+	v = __this_cpu_inc_return(*p);
+	t = __this_cpu_read(pcp->stat_threshold);
+	if (unlikely(v > t)) {
+		s8 overstep = t >> 1;
+
+		node_page_state_add(v + overstep, pgdat, item);
+		__this_cpu_write(*p, -overstep);
+	}
+
+	preempt_enable_nested();
+}
+
+void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
+{
+	__inc_zone_state(page_zone(page), item);
+}
+EXPORT_SYMBOL(__inc_zone_page_state);
+
+void __inc_node_page_state(struct page *page, enum node_stat_item item)
+{
+	__inc_node_state(page_pgdat(page), item);
+}
+EXPORT_SYMBOL(__inc_node_page_state);
+
+void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
+{
+	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
+	s8 __percpu *p = pcp->vm_stat_diff + item;
+	s8 v, t;
+
+	/* See __mod_node_page_state */
+	preempt_disable_nested();
+
+	v = __this_cpu_dec_return(*p);
+	t = __this_cpu_read(pcp->stat_threshold);
+	if (unlikely(v < - t)) {
+		s8 overstep = t >> 1;
+
+		zone_page_state_add(v - overstep, zone, item);
+		__this_cpu_write(*p, overstep);
+	}
+
+	preempt_enable_nested();
+}
+
+void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	s8 v, t;
+
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
+	/* See __mod_node_page_state */
+	preempt_disable_nested();
+
+	v = __this_cpu_dec_return(*p);
+	t = __this_cpu_read(pcp->stat_threshold);
+	if (unlikely(v < - t)) {
+		s8 overstep = t >> 1;
+
+		node_page_state_add(v - overstep, pgdat, item);
+		__this_cpu_write(*p, overstep);
+	}
+
+	preempt_enable_nested();
+}
+
+void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
+{
+	__dec_zone_state(page_zone(page), item);
+}
+EXPORT_SYMBOL(__dec_zone_page_state);
+
+void __dec_node_page_state(struct page *page, enum node_stat_item item)
+{
+	__dec_node_state(page_pgdat(page), item);
+}
+EXPORT_SYMBOL(__dec_node_page_state);
+
+#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
+/*
+ * If we have cmpxchg_local support then we do not need to incur the overhead
+ * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
+ *
+ * mod_state() modifies the zone counter state through atomic per cpu
+ * operations.
+ *
+ * Overstep mode specifies how overstep should handled:
+ *     0       No overstepping
+ *     1       Overstepping half of threshold
+ *     -1      Overstepping minus half of threshold
+*/
+static inline void mod_zone_state(struct zone *zone,
+       enum zone_stat_item item, long delta, int overstep_mode)
+{
+	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
+	s8 __percpu *p = pcp->vm_stat_diff + item;
+	long o, n, t, z;
+
+	do {
+		z = 0;  /* overflow to zone counters */
+
+		/*
+		 * The fetching of the stat_threshold is racy. We may apply
+		 * a counter threshold to the wrong the cpu if we get
+		 * rescheduled while executing here. However, the next
+		 * counter update will apply the threshold again and
+		 * therefore bring the counter under the threshold again.
+		 *
+		 * Most of the time the thresholds are the same anyways
+		 * for all cpus in a zone.
+		 */
+		t = this_cpu_read(pcp->stat_threshold);
+
+		o = this_cpu_read(*p);
+		n = delta + o;
+
+		if (abs(n) > t) {
+			int os = overstep_mode * (t >> 1) ;
+
+			/* Overflow must be added to zone counters */
+			z = n + os;
+			n = -os;
+		}
+	} while (this_cpu_cmpxchg(*p, o, n) != o);
+
+	if (z)
+		zone_page_state_add(z, zone, item);
+}
+
+void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
+			 long delta)
+{
+	mod_zone_state(zone, item, delta, 0);
+}
+EXPORT_SYMBOL(mod_zone_page_state);
+
+void inc_zone_page_state(struct page *page, enum zone_stat_item item)
+{
+	mod_zone_state(page_zone(page), item, 1, 1);
+}
+EXPORT_SYMBOL(inc_zone_page_state);
+
+void dec_zone_page_state(struct page *page, enum zone_stat_item item)
+{
+	mod_zone_state(page_zone(page), item, -1, -1);
+}
+EXPORT_SYMBOL(dec_zone_page_state);
+
+static inline void mod_node_state(struct pglist_data *pgdat,
+       enum node_stat_item item, int delta, int overstep_mode)
+{
+	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
+	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	long o, n, t, z;
+
+	if (vmstat_item_in_bytes(item)) {
+		/*
+		 * Only cgroups use subpage accounting right now; at
+		 * the global level, these items still change in
+		 * multiples of whole pages. Store them as pages
+		 * internally to keep the per-cpu counters compact.
+		 */
+		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
+		delta >>= PAGE_SHIFT;
+	}
+
+	do {
+		z = 0;  /* overflow to node counters */
+
+		/*
+		 * The fetching of the stat_threshold is racy. We may apply
+		 * a counter threshold to the wrong the cpu if we get
+		 * rescheduled while executing here. However, the next
+		 * counter update will apply the threshold again and
+		 * therefore bring the counter under the threshold again.
+		 *
+		 * Most of the time the thresholds are the same anyways
+		 * for all cpus in a node.
+		 */
+		t = this_cpu_read(pcp->stat_threshold);
+
+		o = this_cpu_read(*p);
+		n = delta + o;
+
+		if (abs(n) > t) {
+			int os = overstep_mode * (t >> 1) ;
+
+			/* Overflow must be added to node counters */
+			z = n + os;
+			n = -os;
+		}
+	} while (this_cpu_cmpxchg(*p, o, n) != o);
+
+	if (z)
+		node_page_state_add(z, pgdat, item);
+}
+
+void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+					long delta)
+{
+	mod_node_state(pgdat, item, delta, 0);
+}
+EXPORT_SYMBOL(mod_node_page_state);
+
+void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	mod_node_state(pgdat, item, 1, 1);
+}
+
+void inc_node_page_state(struct page *page, enum node_stat_item item)
+{
+	mod_node_state(page_pgdat(page), item, 1, 1);
+}
+EXPORT_SYMBOL(inc_node_page_state);
+
+void dec_node_page_state(struct page *page, enum node_stat_item item)
+{
+	mod_node_state(page_pgdat(page), item, -1, -1);
+}
+EXPORT_SYMBOL(dec_node_page_state);
+#else
+/*
+ * Use interrupt disable to serialize counter updates
+ */
+void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
+			 long delta)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__mod_zone_page_state(zone, item, delta);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(mod_zone_page_state);
+
+void inc_zone_page_state(struct page *page, enum zone_stat_item item)
+{
+	unsigned long flags;
+	struct zone *zone;
+
+	zone = page_zone(page);
+	local_irq_save(flags);
+	__inc_zone_state(zone, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(inc_zone_page_state);
+
+void dec_zone_page_state(struct page *page, enum zone_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__dec_zone_page_state(page, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(dec_zone_page_state);
+
+void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__inc_node_state(pgdat, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(inc_node_state);
+
+void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+					long delta)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__mod_node_page_state(pgdat, item, delta);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(mod_node_page_state);
+
+void inc_node_page_state(struct page *page, enum node_stat_item item)
+{
+	unsigned long flags;
+	struct pglist_data *pgdat;
+
+	pgdat = page_pgdat(page);
+	local_irq_save(flags);
+	__inc_node_state(pgdat, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(inc_node_page_state);
+
+void dec_node_page_state(struct page *page, enum node_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__dec_node_page_state(page, item);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(dec_node_page_state);
+#endif
+
+/*
+ * Fold a differential into the global counters.
+ * Returns the number of counters updated.
+ */
+static int fold_diff(int *zone_diff, int *node_diff)
+{
+	int i;
+	int changes = 0;
+
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+		if (zone_diff[i]) {
+			atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
+			changes++;
+	}
+
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
+		if (node_diff[i]) {
+			atomic_long_add(node_diff[i], &vm_node_stat[i]);
+			changes++;
+	}
+	return changes;
+}
+
+/*
+ * Update the zone counters for the current cpu.
+ *
+ * Note that refresh_cpu_vm_stats strives to only access
+ * node local memory. The per cpu pagesets on remote zones are placed
+ * in the memory local to the processor using that pageset. So the
+ * loop over all zones will access a series of cachelines local to
+ * the processor.
+ *
+ * The call to zone_page_state_add updates the cachelines with the
+ * statistics in the remote zone struct as well as the global cachelines
+ * with the global counters. These could cause remote node cache line
+ * bouncing and will have to be only done when necessary.
+ *
+ * The function returns the number of global counters updated.
+ */
+static int refresh_cpu_vm_stats(bool do_pagesets)
+{
+	struct pglist_data *pgdat;
+	struct zone *zone;
+	int i;
+	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
+	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
+	int changes = 0;
+
+	for_each_populated_zone(zone) {
+		struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
+#ifdef CONFIG_NUMA
+		struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset;
+#endif
+
+		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
+			int v;
+
+			v = this_cpu_xchg(pzstats->vm_stat_diff[i], 0);
+			if (v) {
+
+				atomic_long_add(v, &zone->vm_stat[i]);
+				global_zone_diff[i] += v;
+#ifdef CONFIG_NUMA
+				/* 3 seconds idle till flush */
+				__this_cpu_write(pcp->expire, 3);
+#endif
+			}
+		}
+#ifdef CONFIG_NUMA
+
+		if (do_pagesets) {
+			cond_resched();
+			/*
+			 * Deal with draining the remote pageset of this
+			 * processor
+			 *
+			 * Check if there are pages remaining in this pageset
+			 * if not then there is nothing to expire.
+			 */
+			if (!__this_cpu_read(pcp->expire) ||
+			       !__this_cpu_read(pcp->count))
+				continue;
+
+			/*
+			 * We never drain zones local to this processor.
+			 */
+			if (zone_to_nid(zone) == numa_node_id()) {
+				__this_cpu_write(pcp->expire, 0);
+				continue;
+			}
+
+			if (__this_cpu_dec_return(pcp->expire))
+				continue;
+
+			if (__this_cpu_read(pcp->count)) {
+				drain_zone_pages(zone, this_cpu_ptr(pcp));
+				changes++;
+			}
+		}
+#endif
+	}
+
+	for_each_online_pgdat(pgdat) {
+		struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
+
+		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+			int v;
+
+			v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
+			if (v) {
+				atomic_long_add(v, &pgdat->vm_stat[i]);
+				global_node_diff[i] += v;
+			}
+		}
+	}
+
+	changes += fold_diff(global_zone_diff, global_node_diff);
+	return changes;
+}
+
+/*
+ * Fold the data for an offline cpu into the global array.
+ * There cannot be any access by the offline cpu and therefore
+ * synchronization is simplified.
+ */
+void cpu_vm_stats_fold(int cpu)
+{
+	struct pglist_data *pgdat;
+	struct zone *zone;
+	int i;
+	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
+	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
+
+	for_each_populated_zone(zone) {
+		struct per_cpu_zonestat *pzstats;
+
+		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
+
+		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
+			if (pzstats->vm_stat_diff[i]) {
+				int v;
+
+				v = pzstats->vm_stat_diff[i];
+				pzstats->vm_stat_diff[i] = 0;
+				atomic_long_add(v, &zone->vm_stat[i]);
+				global_zone_diff[i] += v;
+			}
+		}
+#ifdef CONFIG_NUMA
+		for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
+			if (pzstats->vm_numa_event[i]) {
+				unsigned long v;
+
+				v = pzstats->vm_numa_event[i];
+				pzstats->vm_numa_event[i] = 0;
+				zone_numa_event_add(v, zone, i);
+			}
+		}
+#endif
+	}
+
+	for_each_online_pgdat(pgdat) {
+		struct per_cpu_nodestat *p;
+
+		p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
+
+		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
+			if (p->vm_node_stat_diff[i]) {
+				int v;
+
+				v = p->vm_node_stat_diff[i];
+				p->vm_node_stat_diff[i] = 0;
+				atomic_long_add(v, &pgdat->vm_stat[i]);
+				global_node_diff[i] += v;
+			}
+	}
+
+	fold_diff(global_zone_diff, global_node_diff);
+}
+
+/*
+ * this is only called if !populated_zone(zone), which implies no other users of
+ * pset->vm_stat_diff[] exist.
+ */
+void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
+{
+	unsigned long v;
+	int i;
+
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
+		if (pzstats->vm_stat_diff[i]) {
+			v = pzstats->vm_stat_diff[i];
+			pzstats->vm_stat_diff[i] = 0;
+			zone_page_state_add(v, zone, i);
+		}
+	}
+
+#ifdef CONFIG_NUMA
+	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
+		if (pzstats->vm_numa_event[i]) {
+			v = pzstats->vm_numa_event[i];
+			pzstats->vm_numa_event[i] = 0;
+			zone_numa_event_add(v, zone, i);
+		}
+	}
+#endif
+}
+#endif
+
+#ifdef CONFIG_NUMA
+/*
+ * Determine the per node value of a stat item. This function
+ * is called frequently in a NUMA machine, so try to be as
+ * frugal as possible.
+ */
+unsigned long sum_zone_node_page_state(int node,
+				 enum zone_stat_item item)
+{
+	struct zone *zones = NODE_DATA(node)->node_zones;
+	int i;
+	unsigned long count = 0;
+
+	for (i = 0; i < MAX_NR_ZONES; i++)
+		count += zone_page_state(zones + i, item);
+
+	return count;
+}
+
+/* Determine the per node value of a numa stat item. */
+unsigned long sum_zone_numa_event_state(int node,
+				 enum numa_stat_item item)
+{
+	struct zone *zones = NODE_DATA(node)->node_zones;
+	unsigned long count = 0;
+	int i;
+
+	for (i = 0; i < MAX_NR_ZONES; i++)
+		count += zone_numa_event_state(zones + i, item);
+
+	return count;
+}
+
+/*
+ * Determine the per node value of a stat item.
+ */
+unsigned long node_page_state_pages(struct pglist_data *pgdat,
+				    enum node_stat_item item)
+{
+	long x = atomic_long_read(&pgdat->vm_stat[item]);
+#ifdef CONFIG_SMP
+	if (x < 0)
+		x = 0;
+#endif
+	return x;
+}
+
+unsigned long node_page_state(struct pglist_data *pgdat,
+			      enum node_stat_item item)
+{
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
+	return node_page_state_pages(pgdat, item);
+}
+#endif
+
+#ifdef CONFIG_COMPACTION
+
+struct contig_page_info {
+	unsigned long free_pages;
+	unsigned long free_blocks_total;
+	unsigned long free_blocks_suitable;
+};
+
+/*
+ * Calculate the number of free pages in a zone, how many contiguous
+ * pages are free and how many are large enough to satisfy an allocation of
+ * the target size. Note that this function makes no attempt to estimate
+ * how many suitable free blocks there *might* be if MOVABLE pages were
+ * migrated. Calculating that is possible, but expensive and can be
+ * figured out from userspace
+ */
+static void fill_contig_page_info(struct zone *zone,
+				unsigned int suitable_order,
+				struct contig_page_info *info)
+{
+	unsigned int order;
+
+	info->free_pages = 0;
+	info->free_blocks_total = 0;
+	info->free_blocks_suitable = 0;
+
+	for (order = 0; order <= MAX_ORDER; order++) {
+		unsigned long blocks;
+
+		/*
+		 * Count number of free blocks.
+		 *
+		 * Access to nr_free is lockless as nr_free is used only for
+		 * diagnostic purposes. Use data_race to avoid KCSAN warning.
+		 */
+		blocks = data_race(zone->free_area[order].nr_free);
+		info->free_blocks_total += blocks;
+
+		/* Count free base pages */
+		info->free_pages += blocks << order;
+
+		/* Count the suitable free blocks */
+		if (order >= suitable_order)
+			info->free_blocks_suitable += blocks <<
+						(order - suitable_order);
+	}
+}
+
+/*
+ * A fragmentation index only makes sense if an allocation of a requested
+ * size would fail. If that is true, the fragmentation index indicates
+ * whether external fragmentation or a lack of memory was the problem.
+ * The value can be used to determine if page reclaim or compaction
+ * should be used
+ */
+static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
+{
+	unsigned long requested = 1UL << order;
+
+	if (WARN_ON_ONCE(order > MAX_ORDER))
+		return 0;
+
+	if (!info->free_blocks_total)
+		return 0;
+
+	/* Fragmentation index only makes sense when a request would fail */
+	if (info->free_blocks_suitable)
+		return -1000;
+
+	/*
+	 * Index is between 0 and 1 so return within 3 decimal places
+	 *
+	 * 0 => allocation would fail due to lack of memory
+	 * 1 => allocation would fail due to fragmentation
+	 */
+	return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
+}
+
+/*
+ * Calculates external fragmentation within a zone wrt the given order.
+ * It is defined as the percentage of pages found in blocks of size
+ * less than 1 << order. It returns values in range [0, 100].
+ */
+unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
+{
+	struct contig_page_info info;
+
+	fill_contig_page_info(zone, order, &info);
+	if (info.free_pages == 0)
+		return 0;
+
+	return div_u64((info.free_pages -
+			(info.free_blocks_suitable << order)) * 100,
+			info.free_pages);
+}
+
+/* Same as __fragmentation index but allocs contig_page_info on stack */
+int fragmentation_index(struct zone *zone, unsigned int order)
+{
+	struct contig_page_info info;
+
+	fill_contig_page_info(zone, order, &info);
+	return __fragmentation_index(order, &info);
+}
+#endif
+
+#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
+    defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
+#ifdef CONFIG_ZONE_DMA
+#define TEXT_FOR_DMA(xx) xx "_dma",
+#else
+#define TEXT_FOR_DMA(xx)
+#endif
+
+#ifdef CONFIG_ZONE_DMA32
+#define TEXT_FOR_DMA32(xx) xx "_dma32",
+#else
+#define TEXT_FOR_DMA32(xx)
+#endif
+
+#ifdef CONFIG_HIGHMEM
+#define TEXT_FOR_HIGHMEM(xx) xx "_high",
+#else
+#define TEXT_FOR_HIGHMEM(xx)
+#endif
+
+#ifdef CONFIG_ZONE_DEVICE
+#define TEXT_FOR_DEVICE(xx) xx "_device",
+#else
+#define TEXT_FOR_DEVICE(xx)
+#endif
+
+#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
+					TEXT_FOR_HIGHMEM(xx) xx "_movable", \
+					TEXT_FOR_DEVICE(xx)
+
+const char * const vmstat_text[] = {
+	/* enum zone_stat_item counters */
+	"nr_free_pages",
+	"nr_zone_inactive_anon",
+	"nr_zone_active_anon",
+	"nr_zone_inactive_file",
+	"nr_zone_active_file",
+	"nr_zone_unevictable",
+	"nr_zone_write_pending",
+	"nr_mlock",
+	"nr_bounce",
+#if IS_ENABLED(CONFIG_ZSMALLOC)
+	"nr_zspages",
+#endif
+	"nr_free_cma",
+#ifdef CONFIG_UNACCEPTED_MEMORY
+	"nr_unaccepted",
+#endif
+
+	/* enum numa_stat_item counters */
+#ifdef CONFIG_NUMA
+	"numa_hit",
+	"numa_miss",
+	"numa_foreign",
+	"numa_interleave",
+	"numa_local",
+	"numa_other",
+#endif
+
+	/* enum node_stat_item counters */
+	"nr_inactive_anon",
+	"nr_active_anon",
+	"nr_inactive_file",
+	"nr_active_file",
+	"nr_unevictable",
+	"nr_slab_reclaimable",
+	"nr_slab_unreclaimable",
+	"nr_isolated_anon",
+	"nr_isolated_file",
+	"workingset_nodes",
+	"workingset_refault_anon",
+	"workingset_refault_file",
+	"workingset_activate_anon",
+	"workingset_activate_file",
+	"workingset_restore_anon",
+	"workingset_restore_file",
+	"workingset_nodereclaim",
+	"nr_anon_pages",
+	"nr_mapped",
+	"nr_file_pages",
+	"nr_dirty",
+	"nr_writeback",
+	"nr_writeback_temp",
+	"nr_shmem",
+	"nr_shmem_hugepages",
+	"nr_shmem_pmdmapped",
+	"nr_file_hugepages",
+	"nr_file_pmdmapped",
+	"nr_anon_transparent_hugepages",
+	"nr_vmscan_write",
+	"nr_vmscan_immediate_reclaim",
+	"nr_dirtied",
+	"nr_written",
+	"nr_throttled_written",
+	"nr_kernel_misc_reclaimable",
+	"nr_foll_pin_acquired",
+	"nr_foll_pin_released",
+	"nr_kernel_stack",
+#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
+	"nr_shadow_call_stack",
+#endif
+	"nr_page_table_pages",
+	"nr_sec_page_table_pages",
+#ifdef CONFIG_SWAP
+	"nr_swapcached",
+#endif
+#ifdef CONFIG_NUMA_BALANCING
+	"pgpromote_success",
+	"pgpromote_candidate",
+#endif
+
+	/* enum writeback_stat_item counters */
+	"nr_dirty_threshold",
+	"nr_dirty_background_threshold",
+
+#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
+	/* enum vm_event_item counters */
+	"pgpgin",
+	"pgpgout",
+	"pswpin",
+	"pswpout",
+
+	TEXTS_FOR_ZONES("pgalloc")
+	TEXTS_FOR_ZONES("allocstall")
+	TEXTS_FOR_ZONES("pgskip")
+
+	"pgfree",
+	"pgactivate",
+	"pgdeactivate",
+	"pglazyfree",
+
+	"pgfault",
+	"pgmajfault",
+	"pglazyfreed",
+
+	"pgrefill",
+	"pgreuse",
+	"pgsteal_kswapd",
+	"pgsteal_direct",
+	"pgsteal_khugepaged",
+	"pgdemote_kswapd",
+	"pgdemote_direct",
+	"pgdemote_khugepaged",
+	"pgscan_kswapd",
+	"pgscan_direct",
+	"pgscan_khugepaged",
+	"pgscan_direct_throttle",
+	"pgscan_anon",
+	"pgscan_file",
+	"pgsteal_anon",
+	"pgsteal_file",
+
+#ifdef CONFIG_NUMA
+	"zone_reclaim_failed",
+#endif
+	"pginodesteal",
+	"slabs_scanned",
+	"kswapd_inodesteal",
+	"kswapd_low_wmark_hit_quickly",
+	"kswapd_high_wmark_hit_quickly",
+	"pageoutrun",
+
+	"pgrotated",
+
+	"drop_pagecache",
+	"drop_slab",
+	"oom_kill",
+
+#ifdef CONFIG_NUMA_BALANCING
+	"numa_pte_updates",
+	"numa_huge_pte_updates",
+	"numa_hint_faults",
+	"numa_hint_faults_local",
+	"numa_pages_migrated",
+#endif
+#ifdef CONFIG_MIGRATION
+	"pgmigrate_success",
+	"pgmigrate_fail",
+	"thp_migration_success",
+	"thp_migration_fail",
+	"thp_migration_split",
+#endif
+#ifdef CONFIG_COMPACTION
+	"compact_migrate_scanned",
+	"compact_free_scanned",
+	"compact_isolated",
+	"compact_stall",
+	"compact_fail",
+	"compact_success",
+	"compact_daemon_wake",
+	"compact_daemon_migrate_scanned",
+	"compact_daemon_free_scanned",
+#endif
+
+#ifdef CONFIG_HUGETLB_PAGE
+	"htlb_buddy_alloc_success",
+	"htlb_buddy_alloc_fail",
+#endif
+#ifdef CONFIG_CMA
+	"cma_alloc_success",
+	"cma_alloc_fail",
+#endif
+	"unevictable_pgs_culled",
+	"unevictable_pgs_scanned",
+	"unevictable_pgs_rescued",
+	"unevictable_pgs_mlocked",
+	"unevictable_pgs_munlocked",
+	"unevictable_pgs_cleared",
+	"unevictable_pgs_stranded",
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	"thp_fault_alloc",
+	"thp_fault_fallback",
+	"thp_fault_fallback_charge",
+	"thp_collapse_alloc",
+	"thp_collapse_alloc_failed",
+	"thp_file_alloc",
+	"thp_file_fallback",
+	"thp_file_fallback_charge",
+	"thp_file_mapped",
+	"thp_split_page",
+	"thp_split_page_failed",
+	"thp_deferred_split_page",
+	"thp_split_pmd",
+	"thp_scan_exceed_none_pte",
+	"thp_scan_exceed_swap_pte",
+	"thp_scan_exceed_share_pte",
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+	"thp_split_pud",
+#endif
+	"thp_zero_page_alloc",
+	"thp_zero_page_alloc_failed",
+	"thp_swpout",
+	"thp_swpout_fallback",
+#endif
+#ifdef CONFIG_MEMORY_BALLOON
+	"balloon_inflate",
+	"balloon_deflate",
+#ifdef CONFIG_BALLOON_COMPACTION
+	"balloon_migrate",
+#endif
+#endif /* CONFIG_MEMORY_BALLOON */
+#ifdef CONFIG_DEBUG_TLBFLUSH
+	"nr_tlb_remote_flush",
+	"nr_tlb_remote_flush_received",
+	"nr_tlb_local_flush_all",
+	"nr_tlb_local_flush_one",
+#endif /* CONFIG_DEBUG_TLBFLUSH */
+
+#ifdef CONFIG_SWAP
+	"swap_ra",
+	"swap_ra_hit",
+#ifdef CONFIG_KSM
+	"ksm_swpin_copy",
+#endif
+#endif
+#ifdef CONFIG_KSM
+	"cow_ksm",
+#endif
+#ifdef CONFIG_ZSWAP
+	"zswpin",
+	"zswpout",
+#endif
+#ifdef CONFIG_X86
+	"direct_map_level2_splits",
+	"direct_map_level3_splits",
+#endif
+#ifdef CONFIG_PER_VMA_LOCK_STATS
+	"vma_lock_success",
+	"vma_lock_abort",
+	"vma_lock_retry",
+	"vma_lock_miss",
+#endif
+#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
+};
+#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
+
+#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
+     defined(CONFIG_PROC_FS)
+static void *frag_start(struct seq_file *m, loff_t *pos)
+{
+	pg_data_t *pgdat;
+	loff_t node = *pos;
+
+	for (pgdat = first_online_pgdat();
+	     pgdat && node;
+	     pgdat = next_online_pgdat(pgdat))
+		--node;
+
+	return pgdat;
+}
+
+static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
+{
+	pg_data_t *pgdat = (pg_data_t *)arg;
+
+	(*pos)++;
+	return next_online_pgdat(pgdat);
+}
+
+static void frag_stop(struct seq_file *m, void *arg)
+{
+}
+
+/*
+ * Walk zones in a node and print using a callback.
+ * If @assert_populated is true, only use callback for zones that are populated.
+ */
+static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
+		bool assert_populated, bool nolock,
+		void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
+{
+	struct zone *zone;
+	struct zone *node_zones = pgdat->node_zones;
+	unsigned long flags;
+
+	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
+		if (assert_populated && !populated_zone(zone))
+			continue;
+
+		if (!nolock)
+			spin_lock_irqsave(&zone->lock, flags);
+		print(m, pgdat, zone);
+		if (!nolock)
+			spin_unlock_irqrestore(&zone->lock, flags);
+	}
+}
+#endif
+
+#ifdef CONFIG_PROC_FS
+static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
+						struct zone *zone)
+{
+	int order;
+
+	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
+	for (order = 0; order <= MAX_ORDER; ++order)
+		/*
+		 * Access to nr_free is lockless as nr_free is used only for
+		 * printing purposes. Use data_race to avoid KCSAN warning.
+		 */
+		seq_printf(m, "%6lu ", data_race(zone->free_area[order].nr_free));
+	seq_putc(m, '\n');
+}
+
+/*
+ * This walks the free areas for each zone.
+ */
+static int frag_show(struct seq_file *m, void *arg)
+{
+	pg_data_t *pgdat = (pg_data_t *)arg;
+	walk_zones_in_node(m, pgdat, true, false, frag_show_print);
+	return 0;
+}
+
+static void pagetypeinfo_showfree_print(struct seq_file *m,
+					pg_data_t *pgdat, struct zone *zone)
+{
+	int order, mtype;
+
+	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
+		seq_printf(m, "Node %4d, zone %8s, type %12s ",
+					pgdat->node_id,
+					zone->name,
+					migratetype_names[mtype]);
+		for (order = 0; order <= MAX_ORDER; ++order) {
+			unsigned long freecount = 0;
+			struct free_area *area;
+			struct list_head *curr;
+			bool overflow = false;
+
+			area = &(zone->free_area[order]);
+
+			list_for_each(curr, &area->free_list[mtype]) {
+				/*
+				 * Cap the free_list iteration because it might
+				 * be really large and we are under a spinlock
+				 * so a long time spent here could trigger a
+				 * hard lockup detector. Anyway this is a
+				 * debugging tool so knowing there is a handful
+				 * of pages of this order should be more than
+				 * sufficient.
+				 */
+				if (++freecount >= 100000) {
+					overflow = true;
+					break;
+				}
+			}
+			seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
+			spin_unlock_irq(&zone->lock);
+			cond_resched();
+			spin_lock_irq(&zone->lock);
+		}
+		seq_putc(m, '\n');
+	}
+}
+
+/* Print out the free pages at each order for each migatetype */
+static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
+{
+	int order;
+	pg_data_t *pgdat = (pg_data_t *)arg;
+
+	/* Print header */
+	seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
+	for (order = 0; order <= MAX_ORDER; ++order)
+		seq_printf(m, "%6d ", order);
+	seq_putc(m, '\n');
+
+	walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
+}
+
+static void pagetypeinfo_showblockcount_print(struct seq_file *m,
+					pg_data_t *pgdat, struct zone *zone)
+{
+	int mtype;
+	unsigned long pfn;
+	unsigned long start_pfn = zone->zone_start_pfn;
+	unsigned long end_pfn = zone_end_pfn(zone);
+	unsigned long count[MIGRATE_TYPES] = { 0, };
+
+	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
+		struct page *page;
+
+		page = pfn_to_online_page(pfn);
+		if (!page)
+			continue;
+
+		if (page_zone(page) != zone)
+			continue;
+
+		mtype = get_pageblock_migratetype(page);
+
+		if (mtype < MIGRATE_TYPES)
+			count[mtype]++;
+	}
+
+	/* Print counts */
+	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
+	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
+		seq_printf(m, "%12lu ", count[mtype]);
+	seq_putc(m, '\n');
+}
+
+/* Print out the number of pageblocks for each migratetype */
+static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
+{
+	int mtype;
+	pg_data_t *pgdat = (pg_data_t *)arg;
+
+	seq_printf(m, "\n%-23s", "Number of blocks type ");
+	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
+		seq_printf(m, "%12s ", migratetype_names[mtype]);
+	seq_putc(m, '\n');
+	walk_zones_in_node(m, pgdat, true, false,
+		pagetypeinfo_showblockcount_print);
+}
+
+/*
+ * Print out the number of pageblocks for each migratetype that contain pages
+ * of other types. This gives an indication of how well fallbacks are being
+ * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
+ * to determine what is going on
+ */
+static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
+{
+#ifdef CONFIG_PAGE_OWNER
+	int mtype;
+
+	if (!static_branch_unlikely(&page_owner_inited))
+		return;
+
+	drain_all_pages(NULL);
+
+	seq_printf(m, "\n%-23s", "Number of mixed blocks ");
+	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
+		seq_printf(m, "%12s ", migratetype_names[mtype]);
+	seq_putc(m, '\n');
+
+	walk_zones_in_node(m, pgdat, true, true,
+		pagetypeinfo_showmixedcount_print);
+#endif /* CONFIG_PAGE_OWNER */
+}
+
+/*
+ * This prints out statistics in relation to grouping pages by mobility.
+ * It is expensive to collect so do not constantly read the file.
+ */
+static int pagetypeinfo_show(struct seq_file *m, void *arg)
+{
+	pg_data_t *pgdat = (pg_data_t *)arg;
+
+	/* check memoryless node */
+	if (!node_state(pgdat->node_id, N_MEMORY))
+		return 0;
+
+	seq_printf(m, "Page block order: %d\n", pageblock_order);
+	seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
+	seq_putc(m, '\n');
+	pagetypeinfo_showfree(m, pgdat);
+	pagetypeinfo_showblockcount(m, pgdat);
+	pagetypeinfo_showmixedcount(m, pgdat);
+
+	return 0;
+}
+
+static const struct seq_operations fragmentation_op = {
+	.start	= frag_start,
+	.next	= frag_next,
+	.stop	= frag_stop,
+	.show	= frag_show,
+};
+
+static const struct seq_operations pagetypeinfo_op = {
+	.start	= frag_start,
+	.next	= frag_next,
+	.stop	= frag_stop,
+	.show	= pagetypeinfo_show,
+};
+
+static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
+{
+	int zid;
+
+	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+		struct zone *compare = &pgdat->node_zones[zid];
+
+		if (populated_zone(compare))
+			return zone == compare;
+	}
+
+	return false;
+}
+
+static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
+							struct zone *zone)
+{
+	int i;
+	seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
+	if (is_zone_first_populated(pgdat, zone)) {
+		seq_printf(m, "\n  per-node stats");
+		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+			unsigned long pages = node_page_state_pages(pgdat, i);
+
+			if (vmstat_item_print_in_thp(i))
+				pages /= HPAGE_PMD_NR;
+			seq_printf(m, "\n      %-12s %lu", node_stat_name(i),
+				   pages);
+		}
+	}
+	seq_printf(m,
+		   "\n  pages free     %lu"
+		   "\n        boost    %lu"
+		   "\n        min      %lu"
+		   "\n        low      %lu"
+		   "\n        high     %lu"
+		   "\n        spanned  %lu"
+		   "\n        present  %lu"
+		   "\n        managed  %lu"
+		   "\n        cma      %lu",
+		   zone_page_state(zone, NR_FREE_PAGES),
+		   zone->watermark_boost,
+		   min_wmark_pages(zone),
+		   low_wmark_pages(zone),
+		   high_wmark_pages(zone),
+		   zone->spanned_pages,
+		   zone->present_pages,
+		   zone_managed_pages(zone),
+		   zone_cma_pages(zone));
+
+	seq_printf(m,
+		   "\n        protection: (%ld",
+		   zone->lowmem_reserve[0]);
+	for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
+		seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
+	seq_putc(m, ')');
+
+	/* If unpopulated, no other information is useful */
+	if (!populated_zone(zone)) {
+		seq_putc(m, '\n');
+		return;
+	}
+
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+		seq_printf(m, "\n      %-12s %lu", zone_stat_name(i),
+			   zone_page_state(zone, i));
+
+#ifdef CONFIG_NUMA
+	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
+		seq_printf(m, "\n      %-12s %lu", numa_stat_name(i),
+			   zone_numa_event_state(zone, i));
+#endif
+
+	seq_printf(m, "\n  pagesets");
+	for_each_online_cpu(i) {
+		struct per_cpu_pages *pcp;
+		struct per_cpu_zonestat __maybe_unused *pzstats;
+
+		pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
+		seq_printf(m,
+			   "\n    cpu: %i"
+			   "\n              count: %i"
+			   "\n              high:  %i"
+			   "\n              batch: %i",
+			   i,
+			   pcp->count,
+			   pcp->high,
+			   pcp->batch);
+#ifdef CONFIG_SMP
+		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
+		seq_printf(m, "\n  vm stats threshold: %d",
+				pzstats->stat_threshold);
+#endif
+	}
+	seq_printf(m,
+		   "\n  node_unreclaimable:  %u"
+		   "\n  start_pfn:           %lu",
+		   pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
+		   zone->zone_start_pfn);
+	seq_putc(m, '\n');
+}
+
+/*
+ * Output information about zones in @pgdat.  All zones are printed regardless
+ * of whether they are populated or not: lowmem_reserve_ratio operates on the
+ * set of all zones and userspace would not be aware of such zones if they are
+ * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
+ */
+static int zoneinfo_show(struct seq_file *m, void *arg)
+{
+	pg_data_t *pgdat = (pg_data_t *)arg;
+	walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
+	return 0;
+}
+
+static const struct seq_operations zoneinfo_op = {
+	.start	= frag_start, /* iterate over all zones. The same as in
+			       * fragmentation. */
+	.next	= frag_next,
+	.stop	= frag_stop,
+	.show	= zoneinfo_show,
+};
+
+#define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
+			 NR_VM_NUMA_EVENT_ITEMS + \
+			 NR_VM_NODE_STAT_ITEMS + \
+			 NR_VM_WRITEBACK_STAT_ITEMS + \
+			 (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
+			  NR_VM_EVENT_ITEMS : 0))
+
+static void *vmstat_start(struct seq_file *m, loff_t *pos)
+{
+	unsigned long *v;
+	int i;
+
+	if (*pos >= NR_VMSTAT_ITEMS)
+		return NULL;
+
+	BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
+	fold_vm_numa_events();
+	v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
+	m->private = v;
+	if (!v)
+		return ERR_PTR(-ENOMEM);
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+		v[i] = global_zone_page_state(i);
+	v += NR_VM_ZONE_STAT_ITEMS;
+
+#ifdef CONFIG_NUMA
+	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
+		v[i] = global_numa_event_state(i);
+	v += NR_VM_NUMA_EVENT_ITEMS;
+#endif
+
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+		v[i] = global_node_page_state_pages(i);
+		if (vmstat_item_print_in_thp(i))
+			v[i] /= HPAGE_PMD_NR;
+	}
+	v += NR_VM_NODE_STAT_ITEMS;
+
+	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
+			    v + NR_DIRTY_THRESHOLD);
+	v += NR_VM_WRITEBACK_STAT_ITEMS;
+
+#ifdef CONFIG_VM_EVENT_COUNTERS
+	all_vm_events(v);
+	v[PGPGIN] /= 2;		/* sectors -> kbytes */
+	v[PGPGOUT] /= 2;
+#endif
+	return (unsigned long *)m->private + *pos;
+}
+
+static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
+{
+	(*pos)++;
+	if (*pos >= NR_VMSTAT_ITEMS)
+		return NULL;
+	return (unsigned long *)m->private + *pos;
+}
+
+static int vmstat_show(struct seq_file *m, void *arg)
+{
+	unsigned long *l = arg;
+	unsigned long off = l - (unsigned long *)m->private;
+
+	seq_puts(m, vmstat_text[off]);
+	seq_put_decimal_ull(m, " ", *l);
+	seq_putc(m, '\n');
+
+	if (off == NR_VMSTAT_ITEMS - 1) {
+		/*
+		 * We've come to the end - add any deprecated counters to avoid
+		 * breaking userspace which might depend on them being present.
+		 */
+		seq_puts(m, "nr_unstable 0\n");
+	}
+	return 0;
+}
+
+static void vmstat_stop(struct seq_file *m, void *arg)
+{
+	kfree(m->private);
+	m->private = NULL;
+}
+
+static const struct seq_operations vmstat_op = {
+	.start	= vmstat_start,
+	.next	= vmstat_next,
+	.stop	= vmstat_stop,
+	.show	= vmstat_show,
+};
+#endif /* CONFIG_PROC_FS */
+
+#ifdef CONFIG_SMP
+static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
+int sysctl_stat_interval __read_mostly = HZ;
+
+#ifdef CONFIG_PROC_FS
+static void refresh_vm_stats(struct work_struct *work)
+{
+	refresh_cpu_vm_stats(true);
+}
+
+int vmstat_refresh(struct ctl_table *table, int write,
+		   void *buffer, size_t *lenp, loff_t *ppos)
+{
+	long val;
+	int err;
+	int i;
+
+	/*
+	 * The regular update, every sysctl_stat_interval, may come later
+	 * than expected: leaving a significant amount in per_cpu buckets.
+	 * This is particularly misleading when checking a quantity of HUGE
+	 * pages, immediately after running a test.  /proc/sys/vm/stat_refresh,
+	 * which can equally be echo'ed to or cat'ted from (by root),
+	 * can be used to update the stats just before reading them.
+	 *
+	 * Oh, and since global_zone_page_state() etc. are so careful to hide
+	 * transiently negative values, report an error here if any of
+	 * the stats is negative, so we know to go looking for imbalance.
+	 */
+	err = schedule_on_each_cpu(refresh_vm_stats);
+	if (err)
+		return err;
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
+		/*
+		 * Skip checking stats known to go negative occasionally.
+		 */
+		switch (i) {
+		case NR_ZONE_WRITE_PENDING:
+		case NR_FREE_CMA_PAGES:
+			continue;
+		}
+		val = atomic_long_read(&vm_zone_stat[i]);
+		if (val < 0) {
+			pr_warn("%s: %s %ld\n",
+				__func__, zone_stat_name(i), val);
+		}
+	}
+	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+		/*
+		 * Skip checking stats known to go negative occasionally.
+		 */
+		switch (i) {
+		case NR_WRITEBACK:
+			continue;
+		}
+		val = atomic_long_read(&vm_node_stat[i]);
+		if (val < 0) {
+			pr_warn("%s: %s %ld\n",
+				__func__, node_stat_name(i), val);
+		}
+	}
+	if (write)
+		*ppos += *lenp;
+	else
+		*lenp = 0;
+	return 0;
+}
+#endif /* CONFIG_PROC_FS */
+
+static void vmstat_update(struct work_struct *w)
+{
+	if (refresh_cpu_vm_stats(true)) {
+		/*
+		 * Counters were updated so we expect more updates
+		 * to occur in the future. Keep on running the
+		 * update worker thread.
+		 */
+		queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
+				this_cpu_ptr(&vmstat_work),
+				round_jiffies_relative(sysctl_stat_interval));
+	}
+}
+
+/*
+ * Check if the diffs for a certain cpu indicate that
+ * an update is needed.
+ */
+static bool need_update(int cpu)
+{
+	pg_data_t *last_pgdat = NULL;
+	struct zone *zone;
+
+	for_each_populated_zone(zone) {
+		struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
+		struct per_cpu_nodestat *n;
+
+		/*
+		 * The fast way of checking if there are any vmstat diffs.
+		 */
+		if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
+			return true;
+
+		if (last_pgdat == zone->zone_pgdat)
+			continue;
+		last_pgdat = zone->zone_pgdat;
+		n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
+		if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
+			return true;
+	}
+	return false;
+}
+
+/*
+ * Switch off vmstat processing and then fold all the remaining differentials
+ * until the diffs stay at zero. The function is used by NOHZ and can only be
+ * invoked when tick processing is not active.
+ */
+void quiet_vmstat(void)
+{
+	if (system_state != SYSTEM_RUNNING)
+		return;
+
+	if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
+		return;
+
+	if (!need_update(smp_processor_id()))
+		return;
+
+	/*
+	 * Just refresh counters and do not care about the pending delayed
+	 * vmstat_update. It doesn't fire that often to matter and canceling
+	 * it would be too expensive from this path.
+	 * vmstat_shepherd will take care about that for us.
+	 */
+	refresh_cpu_vm_stats(false);
+}
+
+/*
+ * Shepherd worker thread that checks the
+ * differentials of processors that have their worker
+ * threads for vm statistics updates disabled because of
+ * inactivity.
+ */
+static void vmstat_shepherd(struct work_struct *w);
+
+static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
+
+static void vmstat_shepherd(struct work_struct *w)
+{
+	int cpu;
+
+	cpus_read_lock();
+	/* Check processors whose vmstat worker threads have been disabled */
+	for_each_online_cpu(cpu) {
+		struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
+
+		/*
+		 * In kernel users of vmstat counters either require the precise value and
+		 * they are using zone_page_state_snapshot interface or they can live with
+		 * an imprecision as the regular flushing can happen at arbitrary time and
+		 * cumulative error can grow (see calculate_normal_threshold).
+		 *
+		 * From that POV the regular flushing can be postponed for CPUs that have
+		 * been isolated from the kernel interference without critical
+		 * infrastructure ever noticing. Skip regular flushing from vmstat_shepherd
+		 * for all isolated CPUs to avoid interference with the isolated workload.
+		 */
+		if (cpu_is_isolated(cpu))
+			continue;
+
+		if (!delayed_work_pending(dw) && need_update(cpu))
+			queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
+
+		cond_resched();
+	}
+	cpus_read_unlock();
+
+	schedule_delayed_work(&shepherd,
+		round_jiffies_relative(sysctl_stat_interval));
+}
+
+static void __init start_shepherd_timer(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
+			vmstat_update);
+
+	schedule_delayed_work(&shepherd,
+		round_jiffies_relative(sysctl_stat_interval));
+}
+
+static void __init init_cpu_node_state(void)
+{
+	int node;
+
+	for_each_online_node(node) {
+		if (!cpumask_empty(cpumask_of_node(node)))
+			node_set_state(node, N_CPU);
+	}
+}
+
+static int vmstat_cpu_online(unsigned int cpu)
+{
+	refresh_zone_stat_thresholds();
+
+	if (!node_state(cpu_to_node(cpu), N_CPU)) {
+		node_set_state(cpu_to_node(cpu), N_CPU);
+	}
+
+	return 0;
+}
+
+static int vmstat_cpu_down_prep(unsigned int cpu)
+{
+	cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
+	return 0;
+}
+
+static int vmstat_cpu_dead(unsigned int cpu)
+{
+	const struct cpumask *node_cpus;
+	int node;
+
+	node = cpu_to_node(cpu);
+
+	refresh_zone_stat_thresholds();
+	node_cpus = cpumask_of_node(node);
+	if (!cpumask_empty(node_cpus))
+		return 0;
+
+	node_clear_state(node, N_CPU);
+
+	return 0;
+}
+
+#endif
+
+struct workqueue_struct *mm_percpu_wq;
+
+void __init init_mm_internals(void)
+{
+	int ret __maybe_unused;
+
+	mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
+
+#ifdef CONFIG_SMP
+	ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
+					NULL, vmstat_cpu_dead);
+	if (ret < 0)
+		pr_err("vmstat: failed to register 'dead' hotplug state\n");
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
+					vmstat_cpu_online,
+					vmstat_cpu_down_prep);
+	if (ret < 0)
+		pr_err("vmstat: failed to register 'online' hotplug state\n");
+
+	cpus_read_lock();
+	init_cpu_node_state();
+	cpus_read_unlock();
+
+	start_shepherd_timer();
+#endif
+#ifdef CONFIG_PROC_FS
+	proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
+	proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
+	proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
+	proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
+#endif
+}
+
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
+
+/*
+ * Return an index indicating how much of the available free memory is
+ * unusable for an allocation of the requested size.
+ */
+static int unusable_free_index(unsigned int order,
+				struct contig_page_info *info)
+{
+	/* No free memory is interpreted as all free memory is unusable */
+	if (info->free_pages == 0)
+		return 1000;
+
+	/*
+	 * Index should be a value between 0 and 1. Return a value to 3
+	 * decimal places.
+	 *
+	 * 0 => no fragmentation
+	 * 1 => high fragmentation
+	 */
+	return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
+
+}
+
+static void unusable_show_print(struct seq_file *m,
+					pg_data_t *pgdat, struct zone *zone)
+{
+	unsigned int order;
+	int index;
+	struct contig_page_info info;
+
+	seq_printf(m, "Node %d, zone %8s ",
+				pgdat->node_id,
+				zone->name);
+	for (order = 0; order <= MAX_ORDER; ++order) {
+		fill_contig_page_info(zone, order, &info);
+		index = unusable_free_index(order, &info);
+		seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
+	}
+
+	seq_putc(m, '\n');
+}
+
+/*
+ * Display unusable free space index
+ *
+ * The unusable free space index measures how much of the available free
+ * memory cannot be used to satisfy an allocation of a given size and is a
+ * value between 0 and 1. The higher the value, the more of free memory is
+ * unusable and by implication, the worse the external fragmentation is. This
+ * can be expressed as a percentage by multiplying by 100.
+ */
+static int unusable_show(struct seq_file *m, void *arg)
+{
+	pg_data_t *pgdat = (pg_data_t *)arg;
+
+	/* check memoryless node */
+	if (!node_state(pgdat->node_id, N_MEMORY))
+		return 0;
+
+	walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
+
+	return 0;
+}
+
+static const struct seq_operations unusable_sops = {
+	.start	= frag_start,
+	.next	= frag_next,
+	.stop	= frag_stop,
+	.show	= unusable_show,
+};
+
+DEFINE_SEQ_ATTRIBUTE(unusable);
+
+static void extfrag_show_print(struct seq_file *m,
+					pg_data_t *pgdat, struct zone *zone)
+{
+	unsigned int order;
+	int index;
+
+	/* Alloc on stack as interrupts are disabled for zone walk */
+	struct contig_page_info info;
+
+	seq_printf(m, "Node %d, zone %8s ",
+				pgdat->node_id,
+				zone->name);
+	for (order = 0; order <= MAX_ORDER; ++order) {
+		fill_contig_page_info(zone, order, &info);
+		index = __fragmentation_index(order, &info);
+		seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
+	}
+
+	seq_putc(m, '\n');
+}
+
+/*
+ * Display fragmentation index for orders that allocations would fail for
+ */
+static int extfrag_show(struct seq_file *m, void *arg)
+{
+	pg_data_t *pgdat = (pg_data_t *)arg;
+
+	walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
+
+	return 0;
+}
+
+static const struct seq_operations extfrag_sops = {
+	.start	= frag_start,
+	.next	= frag_next,
+	.stop	= frag_stop,
+	.show	= extfrag_show,
+};
+
+DEFINE_SEQ_ATTRIBUTE(extfrag);
+
+static int __init extfrag_debug_init(void)
+{
+	struct dentry *extfrag_debug_root;
+
+	extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
+
+	debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
+			    &unusable_fops);
+
+	debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
+			    &extfrag_fops);
+
+	return 0;
+}
+
+module_init(extfrag_debug_init);
+#endif