1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/mm/vmstat.c
   4 *
   5 *  Manages VM statistics
   6 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   7 *
   8 *  zoned VM statistics
   9 *  Copyright (C) 2006 Silicon Graphics, Inc.,
  10 *		Christoph Lameter <christoph@lameter.com>
  11 *  Copyright (C) 2008-2014 Christoph Lameter
  12 */
  13#include <linux/fs.h>
  14#include <linux/mm.h>
  15#include <linux/err.h>
  16#include <linux/module.h>
  17#include <linux/slab.h>
  18#include <linux/cpu.h>
  19#include <linux/cpumask.h>
  20#include <linux/vmstat.h>
  21#include <linux/proc_fs.h>
  22#include <linux/seq_file.h>
  23#include <linux/debugfs.h>
  24#include <linux/sched.h>
  25#include <linux/math64.h>
  26#include <linux/writeback.h>
  27#include <linux/compaction.h>
  28#include <linux/mm_inline.h>
  29#include <linux/page_ext.h>
  30#include <linux/page_owner.h>
  31
  32#include "internal.h"
  33
  34#ifdef CONFIG_NUMA
  35int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
  36
  37/* zero numa counters within a zone */
  38static void zero_zone_numa_counters(struct zone *zone)
  39{
  40	int item, cpu;
  41
  42	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++) {
  43		atomic_long_set(&zone->vm_numa_event[item], 0);
  44		for_each_online_cpu(cpu) {
  45			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_event[item]
  46						= 0;
  47		}
  48	}
  49}
  50
  51/* zero numa counters of all the populated zones */
  52static void zero_zones_numa_counters(void)
  53{
  54	struct zone *zone;
  55
  56	for_each_populated_zone(zone)
  57		zero_zone_numa_counters(zone);
  58}
  59
  60/* zero global numa counters */
  61static void zero_global_numa_counters(void)
  62{
  63	int item;
  64
  65	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
  66		atomic_long_set(&vm_numa_event[item], 0);
  67}
  68
  69static void invalid_numa_statistics(void)
  70{
  71	zero_zones_numa_counters();
  72	zero_global_numa_counters();
  73}
  74
  75static DEFINE_MUTEX(vm_numa_stat_lock);
  76
  77int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
  78		void *buffer, size_t *length, loff_t *ppos)
  79{
  80	int ret, oldval;
  81
  82	mutex_lock(&vm_numa_stat_lock);
  83	if (write)
  84		oldval = sysctl_vm_numa_stat;
  85	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
  86	if (ret || !write)
  87		goto out;
  88
  89	if (oldval == sysctl_vm_numa_stat)
  90		goto out;
  91	else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
  92		static_branch_enable(&vm_numa_stat_key);
  93		pr_info("enable numa statistics\n");
  94	} else {
  95		static_branch_disable(&vm_numa_stat_key);
  96		invalid_numa_statistics();
  97		pr_info("disable numa statistics, and clear numa counters\n");
  98	}
  99
 100out:
 101	mutex_unlock(&vm_numa_stat_lock);
 102	return ret;
 103}
 104#endif
 105
 106#ifdef CONFIG_VM_EVENT_COUNTERS
 107DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
 108EXPORT_PER_CPU_SYMBOL(vm_event_states);
 109
 110static void sum_vm_events(unsigned long *ret)
 111{
 112	int cpu;
 113	int i;
 114
 115	memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
 116
 117	for_each_online_cpu(cpu) {
 118		struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
 119
 120		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
 121			ret[i] += this->event[i];
 122	}
 123}
 124
 125/*
 126 * Accumulate the vm event counters across all CPUs.
 127 * The result is unavoidably approximate - it can change
 128 * during and after execution of this function.
 129*/
 130void all_vm_events(unsigned long *ret)
 131{
 132	cpus_read_lock();
 133	sum_vm_events(ret);
 134	cpus_read_unlock();
 135}
 136EXPORT_SYMBOL_GPL(all_vm_events);
 137
 138/*
 139 * Fold the foreign cpu events into our own.
 140 *
 141 * This is adding to the events on one processor
 142 * but keeps the global counts constant.
 143 */
 144void vm_events_fold_cpu(int cpu)
 145{
 146	struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
 147	int i;
 148
 149	for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
 150		count_vm_events(i, fold_state->event[i]);
 151		fold_state->event[i] = 0;
 152	}
 153}
 154
 155#endif /* CONFIG_VM_EVENT_COUNTERS */
 156
 157/*
 158 * Manage combined zone based / global counters
 159 *
 160 * vm_stat contains the global counters
 161 */
 162atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
 163atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
 164atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS] __cacheline_aligned_in_smp;
 165EXPORT_SYMBOL(vm_zone_stat);
 166EXPORT_SYMBOL(vm_node_stat);
 167
 168#ifdef CONFIG_NUMA
 169static void fold_vm_zone_numa_events(struct zone *zone)
 170{
 171	unsigned long zone_numa_events[NR_VM_NUMA_EVENT_ITEMS] = { 0, };
 172	int cpu;
 173	enum numa_stat_item item;
 174
 175	for_each_online_cpu(cpu) {
 176		struct per_cpu_zonestat *pzstats;
 177
 178		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
 179		for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
 180			zone_numa_events[item] += xchg(&pzstats->vm_numa_event[item], 0);
 181	}
 182
 183	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
 184		zone_numa_event_add(zone_numa_events[item], zone, item);
 185}
 186
 187void fold_vm_numa_events(void)
 188{
 189	struct zone *zone;
 190
 191	for_each_populated_zone(zone)
 192		fold_vm_zone_numa_events(zone);
 193}
 194#endif
 195
 196#ifdef CONFIG_SMP
 197
 198int calculate_pressure_threshold(struct zone *zone)
 199{
 200	int threshold;
 201	int watermark_distance;
 202
 203	/*
 204	 * As vmstats are not up to date, there is drift between the estimated
 205	 * and real values. For high thresholds and a high number of CPUs, it
 206	 * is possible for the min watermark to be breached while the estimated
 207	 * value looks fine. The pressure threshold is a reduced value such
 208	 * that even the maximum amount of drift will not accidentally breach
 209	 * the min watermark
 210	 */
 211	watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
 212	threshold = max(1, (int)(watermark_distance / num_online_cpus()));
 213
 214	/*
 215	 * Maximum threshold is 125
 216	 */
 217	threshold = min(125, threshold);
 218
 219	return threshold;
 220}
 221
 222int calculate_normal_threshold(struct zone *zone)
 223{
 224	int threshold;
 225	int mem;	/* memory in 128 MB units */
 226
 227	/*
 228	 * The threshold scales with the number of processors and the amount
 229	 * of memory per zone. More memory means that we can defer updates for
 230	 * longer, more processors could lead to more contention.
 231 	 * fls() is used to have a cheap way of logarithmic scaling.
 232	 *
 233	 * Some sample thresholds:
 234	 *
 235	 * Threshold	Processors	(fls)	Zonesize	fls(mem)+1
 236	 * ------------------------------------------------------------------
 237	 * 8		1		1	0.9-1 GB	4
 238	 * 16		2		2	0.9-1 GB	4
 239	 * 20 		2		2	1-2 GB		5
 240	 * 24		2		2	2-4 GB		6
 241	 * 28		2		2	4-8 GB		7
 242	 * 32		2		2	8-16 GB		8
 243	 * 4		2		2	<128M		1
 244	 * 30		4		3	2-4 GB		5
 245	 * 48		4		3	8-16 GB		8
 246	 * 32		8		4	1-2 GB		4
 247	 * 32		8		4	0.9-1GB		4
 248	 * 10		16		5	<128M		1
 249	 * 40		16		5	900M		4
 250	 * 70		64		7	2-4 GB		5
 251	 * 84		64		7	4-8 GB		6
 252	 * 108		512		9	4-8 GB		6
 253	 * 125		1024		10	8-16 GB		8
 254	 * 125		1024		10	16-32 GB	9
 255	 */
 256
 257	mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
 258
 259	threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 260
 261	/*
 262	 * Maximum threshold is 125
 263	 */
 264	threshold = min(125, threshold);
 265
 266	return threshold;
 267}
 268
 269/*
 270 * Refresh the thresholds for each zone.
 271 */
 272void refresh_zone_stat_thresholds(void)
 273{
 274	struct pglist_data *pgdat;
 275	struct zone *zone;
 276	int cpu;
 277	int threshold;
 278
 279	/* Zero current pgdat thresholds */
 280	for_each_online_pgdat(pgdat) {
 281		for_each_online_cpu(cpu) {
 282			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
 283		}
 284	}
 285
 286	for_each_populated_zone(zone) {
 287		struct pglist_data *pgdat = zone->zone_pgdat;
 288		unsigned long max_drift, tolerate_drift;
 289
 290		threshold = calculate_normal_threshold(zone);
 291
 292		for_each_online_cpu(cpu) {
 293			int pgdat_threshold;
 294
 295			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
 296							= threshold;
 297
 298			/* Base nodestat threshold on the largest populated zone. */
 299			pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
 300			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
 301				= max(threshold, pgdat_threshold);
 302		}
 303
 304		/*
 305		 * Only set percpu_drift_mark if there is a danger that
 306		 * NR_FREE_PAGES reports the low watermark is ok when in fact
 307		 * the min watermark could be breached by an allocation
 308		 */
 309		tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 310		max_drift = num_online_cpus() * threshold;
 311		if (max_drift > tolerate_drift)
 312			zone->percpu_drift_mark = high_wmark_pages(zone) +
 313					max_drift;
 314	}
 315}
 316
 317void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 318				int (*calculate_pressure)(struct zone *))
 319{
 320	struct zone *zone;
 321	int cpu;
 322	int threshold;
 323	int i;
 324
 325	for (i = 0; i < pgdat->nr_zones; i++) {
 326		zone = &pgdat->node_zones[i];
 327		if (!zone->percpu_drift_mark)
 328			continue;
 329
 330		threshold = (*calculate_pressure)(zone);
 331		for_each_online_cpu(cpu)
 332			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
 333							= threshold;
 334	}
 335}
 336
 337/*
 338 * For use when we know that interrupts are disabled,
 339 * or when we know that preemption is disabled and that
 340 * particular counter cannot be updated from interrupt context.
 341 */
 342void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 343			   long delta)
 344{
 345	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 346	s8 __percpu *p = pcp->vm_stat_diff + item;
 347	long x;
 348	long t;
 349
 350	/*
 351	 * Accurate vmstat updates require a RMW. On !PREEMPT_RT kernels,
 352	 * atomicity is provided by IRQs being disabled -- either explicitly
 353	 * or via local_lock_irq. On PREEMPT_RT, local_lock_irq only disables
 354	 * CPU migrations and preemption potentially corrupts a counter so
 355	 * disable preemption.
 356	 */
 357	preempt_disable_nested();
 358
 359	x = delta + __this_cpu_read(*p);
 360
 361	t = __this_cpu_read(pcp->stat_threshold);
 362
 363	if (unlikely(abs(x) > t)) {
 364		zone_page_state_add(x, zone, item);
 365		x = 0;
 366	}
 367	__this_cpu_write(*p, x);
 368
 369	preempt_enable_nested();
 370}
 371EXPORT_SYMBOL(__mod_zone_page_state);
 372
 373void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 374				long delta)
 375{
 376	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 377	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 378	long x;
 379	long t;
 380
 381	if (vmstat_item_in_bytes(item)) {
 382		/*
 383		 * Only cgroups use subpage accounting right now; at
 384		 * the global level, these items still change in
 385		 * multiples of whole pages. Store them as pages
 386		 * internally to keep the per-cpu counters compact.
 387		 */
 388		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
 389		delta >>= PAGE_SHIFT;
 390	}
 391
 392	/* See __mod_node_page_state */
 393	preempt_disable_nested();
 394
 395	x = delta + __this_cpu_read(*p);
 396
 397	t = __this_cpu_read(pcp->stat_threshold);
 398
 399	if (unlikely(abs(x) > t)) {
 400		node_page_state_add(x, pgdat, item);
 401		x = 0;
 402	}
 403	__this_cpu_write(*p, x);
 404
 405	preempt_enable_nested();
 406}
 407EXPORT_SYMBOL(__mod_node_page_state);
 408
 409/*
 410 * Optimized increment and decrement functions.
 411 *
 412 * These are only for a single page and therefore can take a struct page *
 413 * argument instead of struct zone *. This allows the inclusion of the code
 414 * generated for page_zone(page) into the optimized functions.
 415 *
 416 * No overflow check is necessary and therefore the differential can be
 417 * incremented or decremented in place which may allow the compilers to
 418 * generate better code.
 419 * The increment or decrement is known and therefore one boundary check can
 420 * be omitted.
 421 *
 422 * NOTE: These functions are very performance sensitive. Change only
 423 * with care.
 424 *
 425 * Some processors have inc/dec instructions that are atomic vs an interrupt.
 426 * However, the code must first determine the differential location in a zone
 427 * based on the processor number and then inc/dec the counter. There is no
 428 * guarantee without disabling preemption that the processor will not change
 429 * in between and therefore the atomicity vs. interrupt cannot be exploited
 430 * in a useful way here.
 431 */
 432void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 433{
 434	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 435	s8 __percpu *p = pcp->vm_stat_diff + item;
 436	s8 v, t;
 437
 438	/* See __mod_node_page_state */
 439	preempt_disable_nested();
 440
 441	v = __this_cpu_inc_return(*p);
 442	t = __this_cpu_read(pcp->stat_threshold);
 443	if (unlikely(v > t)) {
 444		s8 overstep = t >> 1;
 445
 446		zone_page_state_add(v + overstep, zone, item);
 447		__this_cpu_write(*p, -overstep);
 448	}
 449
 450	preempt_enable_nested();
 451}
 452
 453void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 454{
 455	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 456	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 457	s8 v, t;
 458
 459	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 460
 461	/* See __mod_node_page_state */
 462	preempt_disable_nested();
 463
 464	v = __this_cpu_inc_return(*p);
 465	t = __this_cpu_read(pcp->stat_threshold);
 466	if (unlikely(v > t)) {
 467		s8 overstep = t >> 1;
 468
 469		node_page_state_add(v + overstep, pgdat, item);
 470		__this_cpu_write(*p, -overstep);
 471	}
 472
 473	preempt_enable_nested();
 474}
 475
 476void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 477{
 478	__inc_zone_state(page_zone(page), item);
 479}
 480EXPORT_SYMBOL(__inc_zone_page_state);
 481
 482void __inc_node_page_state(struct page *page, enum node_stat_item item)
 483{
 484	__inc_node_state(page_pgdat(page), item);
 485}
 486EXPORT_SYMBOL(__inc_node_page_state);
 487
 488void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 489{
 490	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 491	s8 __percpu *p = pcp->vm_stat_diff + item;
 492	s8 v, t;
 493
 494	/* See __mod_node_page_state */
 495	preempt_disable_nested();
 496
 497	v = __this_cpu_dec_return(*p);
 498	t = __this_cpu_read(pcp->stat_threshold);
 499	if (unlikely(v < - t)) {
 500		s8 overstep = t >> 1;
 501
 502		zone_page_state_add(v - overstep, zone, item);
 503		__this_cpu_write(*p, overstep);
 504	}
 505
 506	preempt_enable_nested();
 507}
 508
 509void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 510{
 511	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 512	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 513	s8 v, t;
 514
 515	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 516
 517	/* See __mod_node_page_state */
 518	preempt_disable_nested();
 519
 520	v = __this_cpu_dec_return(*p);
 521	t = __this_cpu_read(pcp->stat_threshold);
 522	if (unlikely(v < - t)) {
 523		s8 overstep = t >> 1;
 524
 525		node_page_state_add(v - overstep, pgdat, item);
 526		__this_cpu_write(*p, overstep);
 527	}
 528
 529	preempt_enable_nested();
 530}
 531
 532void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 533{
 534	__dec_zone_state(page_zone(page), item);
 535}
 536EXPORT_SYMBOL(__dec_zone_page_state);
 537
 538void __dec_node_page_state(struct page *page, enum node_stat_item item)
 539{
 540	__dec_node_state(page_pgdat(page), item);
 541}
 542EXPORT_SYMBOL(__dec_node_page_state);
 543
 544#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 545/*
 546 * If we have cmpxchg_local support then we do not need to incur the overhead
 547 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 548 *
 549 * mod_state() modifies the zone counter state through atomic per cpu
 550 * operations.
 551 *
 552 * Overstep mode specifies how overstep should handled:
 553 *     0       No overstepping
 554 *     1       Overstepping half of threshold
 555 *     -1      Overstepping minus half of threshold
 556*/
 557static inline void mod_zone_state(struct zone *zone,
 558       enum zone_stat_item item, long delta, int overstep_mode)
 559{
 560	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 561	s8 __percpu *p = pcp->vm_stat_diff + item;
 562	long o, n, t, z;
 563
 564	do {
 565		z = 0;  /* overflow to zone counters */
 566
 567		/*
 568		 * The fetching of the stat_threshold is racy. We may apply
 569		 * a counter threshold to the wrong the cpu if we get
 570		 * rescheduled while executing here. However, the next
 571		 * counter update will apply the threshold again and
 572		 * therefore bring the counter under the threshold again.
 573		 *
 574		 * Most of the time the thresholds are the same anyways
 575		 * for all cpus in a zone.
 576		 */
 577		t = this_cpu_read(pcp->stat_threshold);
 578
 579		o = this_cpu_read(*p);
 580		n = delta + o;
 581
 582		if (abs(n) > t) {
 583			int os = overstep_mode * (t >> 1) ;
 584
 585			/* Overflow must be added to zone counters */
 586			z = n + os;
 587			n = -os;
 588		}
 589	} while (this_cpu_cmpxchg(*p, o, n) != o);
 590
 591	if (z)
 592		zone_page_state_add(z, zone, item);
 593}
 594
 595void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 596			 long delta)
 597{
 598	mod_zone_state(zone, item, delta, 0);
 599}
 600EXPORT_SYMBOL(mod_zone_page_state);
 601
 602void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 603{
 604	mod_zone_state(page_zone(page), item, 1, 1);
 605}
 606EXPORT_SYMBOL(inc_zone_page_state);
 607
 608void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 609{
 610	mod_zone_state(page_zone(page), item, -1, -1);
 611}
 612EXPORT_SYMBOL(dec_zone_page_state);
 613
 614static inline void mod_node_state(struct pglist_data *pgdat,
 615       enum node_stat_item item, int delta, int overstep_mode)
 616{
 617	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 618	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 619	long o, n, t, z;
 620
 621	if (vmstat_item_in_bytes(item)) {
 622		/*
 623		 * Only cgroups use subpage accounting right now; at
 624		 * the global level, these items still change in
 625		 * multiples of whole pages. Store them as pages
 626		 * internally to keep the per-cpu counters compact.
 627		 */
 628		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
 629		delta >>= PAGE_SHIFT;
 630	}
 631
 632	do {
 633		z = 0;  /* overflow to node counters */
 634
 635		/*
 636		 * The fetching of the stat_threshold is racy. We may apply
 637		 * a counter threshold to the wrong the cpu if we get
 638		 * rescheduled while executing here. However, the next
 639		 * counter update will apply the threshold again and
 640		 * therefore bring the counter under the threshold again.
 641		 *
 642		 * Most of the time the thresholds are the same anyways
 643		 * for all cpus in a node.
 644		 */
 645		t = this_cpu_read(pcp->stat_threshold);
 646
 647		o = this_cpu_read(*p);
 648		n = delta + o;
 649
 650		if (abs(n) > t) {
 651			int os = overstep_mode * (t >> 1) ;
 652
 653			/* Overflow must be added to node counters */
 654			z = n + os;
 655			n = -os;
 656		}
 657	} while (this_cpu_cmpxchg(*p, o, n) != o);
 658
 659	if (z)
 660		node_page_state_add(z, pgdat, item);
 661}
 662
 663void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 664					long delta)
 665{
 666	mod_node_state(pgdat, item, delta, 0);
 667}
 668EXPORT_SYMBOL(mod_node_page_state);
 669
 670void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 671{
 672	mod_node_state(pgdat, item, 1, 1);
 673}
 674
 675void inc_node_page_state(struct page *page, enum node_stat_item item)
 676{
 677	mod_node_state(page_pgdat(page), item, 1, 1);
 678}
 679EXPORT_SYMBOL(inc_node_page_state);
 680
 681void dec_node_page_state(struct page *page, enum node_stat_item item)
 682{
 683	mod_node_state(page_pgdat(page), item, -1, -1);
 684}
 685EXPORT_SYMBOL(dec_node_page_state);
 686#else
 687/*
 688 * Use interrupt disable to serialize counter updates
 689 */
 690void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 691			 long delta)
 692{
 693	unsigned long flags;
 694
 695	local_irq_save(flags);
 696	__mod_zone_page_state(zone, item, delta);
 697	local_irq_restore(flags);
 698}
 699EXPORT_SYMBOL(mod_zone_page_state);
 700
 701void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 702{
 703	unsigned long flags;
 704	struct zone *zone;
 705
 706	zone = page_zone(page);
 707	local_irq_save(flags);
 708	__inc_zone_state(zone, item);
 709	local_irq_restore(flags);
 710}
 711EXPORT_SYMBOL(inc_zone_page_state);
 712
 713void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 714{
 715	unsigned long flags;
 716
 717	local_irq_save(flags);
 718	__dec_zone_page_state(page, item);
 719	local_irq_restore(flags);
 720}
 721EXPORT_SYMBOL(dec_zone_page_state);
 722
 723void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 724{
 725	unsigned long flags;
 726
 727	local_irq_save(flags);
 728	__inc_node_state(pgdat, item);
 729	local_irq_restore(flags);
 730}
 731EXPORT_SYMBOL(inc_node_state);
 732
 733void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 734					long delta)
 735{
 736	unsigned long flags;
 737
 738	local_irq_save(flags);
 739	__mod_node_page_state(pgdat, item, delta);
 740	local_irq_restore(flags);
 741}
 742EXPORT_SYMBOL(mod_node_page_state);
 743
 744void inc_node_page_state(struct page *page, enum node_stat_item item)
 745{
 746	unsigned long flags;
 747	struct pglist_data *pgdat;
 748
 749	pgdat = page_pgdat(page);
 750	local_irq_save(flags);
 751	__inc_node_state(pgdat, item);
 752	local_irq_restore(flags);
 753}
 754EXPORT_SYMBOL(inc_node_page_state);
 755
 756void dec_node_page_state(struct page *page, enum node_stat_item item)
 757{
 758	unsigned long flags;
 759
 760	local_irq_save(flags);
 761	__dec_node_page_state(page, item);
 762	local_irq_restore(flags);
 763}
 764EXPORT_SYMBOL(dec_node_page_state);
 765#endif
 766
 767/*
 768 * Fold a differential into the global counters.
 769 * Returns the number of counters updated.
 770 */
 771static int fold_diff(int *zone_diff, int *node_diff)
 772{
 773	int i;
 774	int changes = 0;
 775
 776	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 777		if (zone_diff[i]) {
 778			atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
 779			changes++;
 780	}
 781
 782	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 783		if (node_diff[i]) {
 784			atomic_long_add(node_diff[i], &vm_node_stat[i]);
 785			changes++;
 786	}
 787	return changes;
 788}
 789
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 790/*
 791 * Update the zone counters for the current cpu.
 792 *
 793 * Note that refresh_cpu_vm_stats strives to only access
 794 * node local memory. The per cpu pagesets on remote zones are placed
 795 * in the memory local to the processor using that pageset. So the
 796 * loop over all zones will access a series of cachelines local to
 797 * the processor.
 798 *
 799 * The call to zone_page_state_add updates the cachelines with the
 800 * statistics in the remote zone struct as well as the global cachelines
 801 * with the global counters. These could cause remote node cache line
 802 * bouncing and will have to be only done when necessary.
 803 *
 804 * The function returns the number of global counters updated.
 805 */
 806static int refresh_cpu_vm_stats(bool do_pagesets)
 807{
 808	struct pglist_data *pgdat;
 809	struct zone *zone;
 810	int i;
 811	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 812	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 813	int changes = 0;
 814
 815	for_each_populated_zone(zone) {
 816		struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
 817#ifdef CONFIG_NUMA
 818		struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset;
 819#endif
 820
 821		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 822			int v;
 823
 824			v = this_cpu_xchg(pzstats->vm_stat_diff[i], 0);
 825			if (v) {
 826
 827				atomic_long_add(v, &zone->vm_stat[i]);
 828				global_zone_diff[i] += v;
 829#ifdef CONFIG_NUMA
 830				/* 3 seconds idle till flush */
 831				__this_cpu_write(pcp->expire, 3);
 832#endif
 833			}
 834		}
 835#ifdef CONFIG_NUMA
 836
 837		if (do_pagesets) {
 838			cond_resched();
 839			/*
 840			 * Deal with draining the remote pageset of this
 841			 * processor
 842			 *
 843			 * Check if there are pages remaining in this pageset
 844			 * if not then there is nothing to expire.
 845			 */
 846			if (!__this_cpu_read(pcp->expire) ||
 847			       !__this_cpu_read(pcp->count))
 848				continue;
 849
 850			/*
 851			 * We never drain zones local to this processor.
 852			 */
 853			if (zone_to_nid(zone) == numa_node_id()) {
 854				__this_cpu_write(pcp->expire, 0);
 855				continue;
 856			}
 857
 858			if (__this_cpu_dec_return(pcp->expire))
 859				continue;
 860
 861			if (__this_cpu_read(pcp->count)) {
 862				drain_zone_pages(zone, this_cpu_ptr(pcp));
 863				changes++;
 864			}
 865		}
 866#endif
 867	}
 868
 869	for_each_online_pgdat(pgdat) {
 870		struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
 871
 872		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
 873			int v;
 874
 875			v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
 876			if (v) {
 877				atomic_long_add(v, &pgdat->vm_stat[i]);
 878				global_node_diff[i] += v;
 879			}
 880		}
 881	}
 882
 883	changes += fold_diff(global_zone_diff, global_node_diff);
 884	return changes;
 885}
 886
 887/*
 888 * Fold the data for an offline cpu into the global array.
 889 * There cannot be any access by the offline cpu and therefore
 890 * synchronization is simplified.
 891 */
 892void cpu_vm_stats_fold(int cpu)
 893{
 894	struct pglist_data *pgdat;
 895	struct zone *zone;
 896	int i;
 897	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 898	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 899
 900	for_each_populated_zone(zone) {
 901		struct per_cpu_zonestat *pzstats;
 902
 903		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
 904
 905		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 906			if (pzstats->vm_stat_diff[i]) {
 907				int v;
 908
 909				v = pzstats->vm_stat_diff[i];
 910				pzstats->vm_stat_diff[i] = 0;
 911				atomic_long_add(v, &zone->vm_stat[i]);
 912				global_zone_diff[i] += v;
 913			}
 914		}
 915#ifdef CONFIG_NUMA
 916		for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
 917			if (pzstats->vm_numa_event[i]) {
 918				unsigned long v;
 919
 920				v = pzstats->vm_numa_event[i];
 921				pzstats->vm_numa_event[i] = 0;
 922				zone_numa_event_add(v, zone, i);
 923			}
 924		}
 925#endif
 926	}
 927
 928	for_each_online_pgdat(pgdat) {
 929		struct per_cpu_nodestat *p;
 930
 931		p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
 932
 933		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 934			if (p->vm_node_stat_diff[i]) {
 935				int v;
 936
 937				v = p->vm_node_stat_diff[i];
 938				p->vm_node_stat_diff[i] = 0;
 939				atomic_long_add(v, &pgdat->vm_stat[i]);
 940				global_node_diff[i] += v;
 941			}
 942	}
 943
 944	fold_diff(global_zone_diff, global_node_diff);
 945}
 946
 947/*
 948 * this is only called if !populated_zone(zone), which implies no other users of
 949 * pset->vm_stat_diff[] exist.
 950 */
 951void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
 952{
 953	unsigned long v;
 954	int i;
 955
 956	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 957		if (pzstats->vm_stat_diff[i]) {
 958			v = pzstats->vm_stat_diff[i];
 959			pzstats->vm_stat_diff[i] = 0;
 960			zone_page_state_add(v, zone, i);
 961		}
 962	}
 963
 964#ifdef CONFIG_NUMA
 965	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
 966		if (pzstats->vm_numa_event[i]) {
 967			v = pzstats->vm_numa_event[i];
 968			pzstats->vm_numa_event[i] = 0;
 969			zone_numa_event_add(v, zone, i);
 970		}
 971	}
 972#endif
 973}
 974#endif
 975
 976#ifdef CONFIG_NUMA
 977/*
 978 * Determine the per node value of a stat item. This function
 979 * is called frequently in a NUMA machine, so try to be as
 980 * frugal as possible.
 981 */
 982unsigned long sum_zone_node_page_state(int node,
 983				 enum zone_stat_item item)
 984{
 985	struct zone *zones = NODE_DATA(node)->node_zones;
 986	int i;
 987	unsigned long count = 0;
 988
 989	for (i = 0; i < MAX_NR_ZONES; i++)
 990		count += zone_page_state(zones + i, item);
 991
 992	return count;
 993}
 994
 995/* Determine the per node value of a numa stat item. */
 996unsigned long sum_zone_numa_event_state(int node,
 997				 enum numa_stat_item item)
 998{
 999	struct zone *zones = NODE_DATA(node)->node_zones;
1000	unsigned long count = 0;
1001	int i;
1002
1003	for (i = 0; i < MAX_NR_ZONES; i++)
1004		count += zone_numa_event_state(zones + i, item);
1005
1006	return count;
1007}
1008
1009/*
1010 * Determine the per node value of a stat item.
1011 */
1012unsigned long node_page_state_pages(struct pglist_data *pgdat,
1013				    enum node_stat_item item)
1014{
1015	long x = atomic_long_read(&pgdat->vm_stat[item]);
1016#ifdef CONFIG_SMP
1017	if (x < 0)
1018		x = 0;
1019#endif
1020	return x;
1021}
1022
1023unsigned long node_page_state(struct pglist_data *pgdat,
1024			      enum node_stat_item item)
1025{
1026	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
1027
1028	return node_page_state_pages(pgdat, item);
1029}
1030#endif
1031
1032#ifdef CONFIG_COMPACTION
1033
1034struct contig_page_info {
1035	unsigned long free_pages;
1036	unsigned long free_blocks_total;
1037	unsigned long free_blocks_suitable;
1038};
1039
1040/*
1041 * Calculate the number of free pages in a zone, how many contiguous
1042 * pages are free and how many are large enough to satisfy an allocation of
1043 * the target size. Note that this function makes no attempt to estimate
1044 * how many suitable free blocks there *might* be if MOVABLE pages were
1045 * migrated. Calculating that is possible, but expensive and can be
1046 * figured out from userspace
1047 */
1048static void fill_contig_page_info(struct zone *zone,
1049				unsigned int suitable_order,
1050				struct contig_page_info *info)
1051{
1052	unsigned int order;
1053
1054	info->free_pages = 0;
1055	info->free_blocks_total = 0;
1056	info->free_blocks_suitable = 0;
1057
1058	for (order = 0; order < MAX_ORDER; order++) {
1059		unsigned long blocks;
1060
1061		/*
1062		 * Count number of free blocks.
1063		 *
1064		 * Access to nr_free is lockless as nr_free is used only for
1065		 * diagnostic purposes. Use data_race to avoid KCSAN warning.
1066		 */
1067		blocks = data_race(zone->free_area[order].nr_free);
1068		info->free_blocks_total += blocks;
1069
1070		/* Count free base pages */
1071		info->free_pages += blocks << order;
1072
1073		/* Count the suitable free blocks */
1074		if (order >= suitable_order)
1075			info->free_blocks_suitable += blocks <<
1076						(order - suitable_order);
1077	}
1078}
1079
1080/*
1081 * A fragmentation index only makes sense if an allocation of a requested
1082 * size would fail. If that is true, the fragmentation index indicates
1083 * whether external fragmentation or a lack of memory was the problem.
1084 * The value can be used to determine if page reclaim or compaction
1085 * should be used
1086 */
1087static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
1088{
1089	unsigned long requested = 1UL << order;
1090
1091	if (WARN_ON_ONCE(order >= MAX_ORDER))
1092		return 0;
1093
1094	if (!info->free_blocks_total)
1095		return 0;
1096
1097	/* Fragmentation index only makes sense when a request would fail */
1098	if (info->free_blocks_suitable)
1099		return -1000;
1100
1101	/*
1102	 * Index is between 0 and 1 so return within 3 decimal places
1103	 *
1104	 * 0 => allocation would fail due to lack of memory
1105	 * 1 => allocation would fail due to fragmentation
1106	 */
1107	return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
1108}
1109
1110/*
1111 * Calculates external fragmentation within a zone wrt the given order.
1112 * It is defined as the percentage of pages found in blocks of size
1113 * less than 1 << order. It returns values in range [0, 100].
1114 */
1115unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
1116{
1117	struct contig_page_info info;
1118
1119	fill_contig_page_info(zone, order, &info);
1120	if (info.free_pages == 0)
1121		return 0;
1122
1123	return div_u64((info.free_pages -
1124			(info.free_blocks_suitable << order)) * 100,
1125			info.free_pages);
1126}
1127
1128/* Same as __fragmentation index but allocs contig_page_info on stack */
1129int fragmentation_index(struct zone *zone, unsigned int order)
1130{
1131	struct contig_page_info info;
1132
1133	fill_contig_page_info(zone, order, &info);
1134	return __fragmentation_index(order, &info);
1135}
1136#endif
1137
1138#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
1139    defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
1140#ifdef CONFIG_ZONE_DMA
1141#define TEXT_FOR_DMA(xx) xx "_dma",
1142#else
1143#define TEXT_FOR_DMA(xx)
1144#endif
1145
1146#ifdef CONFIG_ZONE_DMA32
1147#define TEXT_FOR_DMA32(xx) xx "_dma32",
1148#else
1149#define TEXT_FOR_DMA32(xx)
1150#endif
1151
1152#ifdef CONFIG_HIGHMEM
1153#define TEXT_FOR_HIGHMEM(xx) xx "_high",
1154#else
1155#define TEXT_FOR_HIGHMEM(xx)
1156#endif
1157
1158#ifdef CONFIG_ZONE_DEVICE
1159#define TEXT_FOR_DEVICE(xx) xx "_device",
1160#else
1161#define TEXT_FOR_DEVICE(xx)
1162#endif
1163
1164#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
1165					TEXT_FOR_HIGHMEM(xx) xx "_movable", \
1166					TEXT_FOR_DEVICE(xx)
1167
1168const char * const vmstat_text[] = {
1169	/* enum zone_stat_item counters */
1170	"nr_free_pages",
1171	"nr_zone_inactive_anon",
1172	"nr_zone_active_anon",
1173	"nr_zone_inactive_file",
1174	"nr_zone_active_file",
1175	"nr_zone_unevictable",
1176	"nr_zone_write_pending",
1177	"nr_mlock",
1178	"nr_bounce",
1179#if IS_ENABLED(CONFIG_ZSMALLOC)
1180	"nr_zspages",
1181#endif
1182	"nr_free_cma",
1183
1184	/* enum numa_stat_item counters */
1185#ifdef CONFIG_NUMA
1186	"numa_hit",
1187	"numa_miss",
1188	"numa_foreign",
1189	"numa_interleave",
1190	"numa_local",
1191	"numa_other",
1192#endif
1193
1194	/* enum node_stat_item counters */
1195	"nr_inactive_anon",
1196	"nr_active_anon",
1197	"nr_inactive_file",
1198	"nr_active_file",
1199	"nr_unevictable",
1200	"nr_slab_reclaimable",
1201	"nr_slab_unreclaimable",
1202	"nr_isolated_anon",
1203	"nr_isolated_file",
1204	"workingset_nodes",
1205	"workingset_refault_anon",
1206	"workingset_refault_file",
1207	"workingset_activate_anon",
1208	"workingset_activate_file",
1209	"workingset_restore_anon",
1210	"workingset_restore_file",
1211	"workingset_nodereclaim",
1212	"nr_anon_pages",
1213	"nr_mapped",
1214	"nr_file_pages",
1215	"nr_dirty",
1216	"nr_writeback",
1217	"nr_writeback_temp",
1218	"nr_shmem",
1219	"nr_shmem_hugepages",
1220	"nr_shmem_pmdmapped",
1221	"nr_file_hugepages",
1222	"nr_file_pmdmapped",
1223	"nr_anon_transparent_hugepages",
1224	"nr_vmscan_write",
1225	"nr_vmscan_immediate_reclaim",
1226	"nr_dirtied",
1227	"nr_written",
1228	"nr_throttled_written",
1229	"nr_kernel_misc_reclaimable",
1230	"nr_foll_pin_acquired",
1231	"nr_foll_pin_released",
1232	"nr_kernel_stack",
1233#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
1234	"nr_shadow_call_stack",
1235#endif
1236	"nr_page_table_pages",
1237	"nr_sec_page_table_pages",
1238#ifdef CONFIG_SWAP
1239	"nr_swapcached",
1240#endif
1241#ifdef CONFIG_NUMA_BALANCING
1242	"pgpromote_success",
1243	"pgpromote_candidate",
1244#endif
1245
1246	/* enum writeback_stat_item counters */
1247	"nr_dirty_threshold",
1248	"nr_dirty_background_threshold",
1249
1250#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
1251	/* enum vm_event_item counters */
1252	"pgpgin",
1253	"pgpgout",
1254	"pswpin",
1255	"pswpout",
1256
1257	TEXTS_FOR_ZONES("pgalloc")
1258	TEXTS_FOR_ZONES("allocstall")
1259	TEXTS_FOR_ZONES("pgskip")
1260
1261	"pgfree",
1262	"pgactivate",
1263	"pgdeactivate",
1264	"pglazyfree",
1265
1266	"pgfault",
1267	"pgmajfault",
1268	"pglazyfreed",
1269
1270	"pgrefill",
1271	"pgreuse",
1272	"pgsteal_kswapd",
1273	"pgsteal_direct",
1274	"pgsteal_khugepaged",
1275	"pgdemote_kswapd",
1276	"pgdemote_direct",
1277	"pgdemote_khugepaged",
1278	"pgscan_kswapd",
1279	"pgscan_direct",
1280	"pgscan_khugepaged",
1281	"pgscan_direct_throttle",
1282	"pgscan_anon",
1283	"pgscan_file",
1284	"pgsteal_anon",
1285	"pgsteal_file",
1286
1287#ifdef CONFIG_NUMA
1288	"zone_reclaim_failed",
1289#endif
1290	"pginodesteal",
1291	"slabs_scanned",
1292	"kswapd_inodesteal",
1293	"kswapd_low_wmark_hit_quickly",
1294	"kswapd_high_wmark_hit_quickly",
1295	"pageoutrun",
1296
1297	"pgrotated",
1298
1299	"drop_pagecache",
1300	"drop_slab",
1301	"oom_kill",
1302
1303#ifdef CONFIG_NUMA_BALANCING
1304	"numa_pte_updates",
1305	"numa_huge_pte_updates",
1306	"numa_hint_faults",
1307	"numa_hint_faults_local",
1308	"numa_pages_migrated",
1309#endif
1310#ifdef CONFIG_MIGRATION
1311	"pgmigrate_success",
1312	"pgmigrate_fail",
1313	"thp_migration_success",
1314	"thp_migration_fail",
1315	"thp_migration_split",
1316#endif
1317#ifdef CONFIG_COMPACTION
1318	"compact_migrate_scanned",
1319	"compact_free_scanned",
1320	"compact_isolated",
1321	"compact_stall",
1322	"compact_fail",
1323	"compact_success",
1324	"compact_daemon_wake",
1325	"compact_daemon_migrate_scanned",
1326	"compact_daemon_free_scanned",
1327#endif
1328
1329#ifdef CONFIG_HUGETLB_PAGE
1330	"htlb_buddy_alloc_success",
1331	"htlb_buddy_alloc_fail",
1332#endif
1333#ifdef CONFIG_CMA
1334	"cma_alloc_success",
1335	"cma_alloc_fail",
1336#endif
1337	"unevictable_pgs_culled",
1338	"unevictable_pgs_scanned",
1339	"unevictable_pgs_rescued",
1340	"unevictable_pgs_mlocked",
1341	"unevictable_pgs_munlocked",
1342	"unevictable_pgs_cleared",
1343	"unevictable_pgs_stranded",
1344
1345#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1346	"thp_fault_alloc",
1347	"thp_fault_fallback",
1348	"thp_fault_fallback_charge",
1349	"thp_collapse_alloc",
1350	"thp_collapse_alloc_failed",
1351	"thp_file_alloc",
1352	"thp_file_fallback",
1353	"thp_file_fallback_charge",
1354	"thp_file_mapped",
1355	"thp_split_page",
1356	"thp_split_page_failed",
1357	"thp_deferred_split_page",
1358	"thp_split_pmd",
1359	"thp_scan_exceed_none_pte",
1360	"thp_scan_exceed_swap_pte",
1361	"thp_scan_exceed_share_pte",
1362#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1363	"thp_split_pud",
1364#endif
1365	"thp_zero_page_alloc",
1366	"thp_zero_page_alloc_failed",
1367	"thp_swpout",
1368	"thp_swpout_fallback",
1369#endif
1370#ifdef CONFIG_MEMORY_BALLOON
1371	"balloon_inflate",
1372	"balloon_deflate",
1373#ifdef CONFIG_BALLOON_COMPACTION
1374	"balloon_migrate",
1375#endif
1376#endif /* CONFIG_MEMORY_BALLOON */
1377#ifdef CONFIG_DEBUG_TLBFLUSH
1378	"nr_tlb_remote_flush",
1379	"nr_tlb_remote_flush_received",
1380	"nr_tlb_local_flush_all",
1381	"nr_tlb_local_flush_one",
1382#endif /* CONFIG_DEBUG_TLBFLUSH */
1383
 
 
 
 
1384#ifdef CONFIG_SWAP
1385	"swap_ra",
1386	"swap_ra_hit",
1387#ifdef CONFIG_KSM
1388	"ksm_swpin_copy",
1389#endif
1390#endif
1391#ifdef CONFIG_KSM
1392	"cow_ksm",
1393#endif
1394#ifdef CONFIG_ZSWAP
1395	"zswpin",
1396	"zswpout",
1397#endif
1398#ifdef CONFIG_X86
1399	"direct_map_level2_splits",
1400	"direct_map_level3_splits",
1401#endif
1402#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
1403};
1404#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
1405
1406#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1407     defined(CONFIG_PROC_FS)
1408static void *frag_start(struct seq_file *m, loff_t *pos)
1409{
1410	pg_data_t *pgdat;
1411	loff_t node = *pos;
1412
1413	for (pgdat = first_online_pgdat();
1414	     pgdat && node;
1415	     pgdat = next_online_pgdat(pgdat))
1416		--node;
1417
1418	return pgdat;
1419}
1420
1421static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1422{
1423	pg_data_t *pgdat = (pg_data_t *)arg;
1424
1425	(*pos)++;
1426	return next_online_pgdat(pgdat);
1427}
1428
1429static void frag_stop(struct seq_file *m, void *arg)
1430{
1431}
1432
1433/*
1434 * Walk zones in a node and print using a callback.
1435 * If @assert_populated is true, only use callback for zones that are populated.
1436 */
1437static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1438		bool assert_populated, bool nolock,
1439		void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1440{
1441	struct zone *zone;
1442	struct zone *node_zones = pgdat->node_zones;
1443	unsigned long flags;
1444
1445	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1446		if (assert_populated && !populated_zone(zone))
1447			continue;
1448
1449		if (!nolock)
1450			spin_lock_irqsave(&zone->lock, flags);
1451		print(m, pgdat, zone);
1452		if (!nolock)
1453			spin_unlock_irqrestore(&zone->lock, flags);
1454	}
1455}
1456#endif
1457
1458#ifdef CONFIG_PROC_FS
1459static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1460						struct zone *zone)
1461{
1462	int order;
1463
1464	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1465	for (order = 0; order < MAX_ORDER; ++order)
1466		/*
1467		 * Access to nr_free is lockless as nr_free is used only for
1468		 * printing purposes. Use data_race to avoid KCSAN warning.
1469		 */
1470		seq_printf(m, "%6lu ", data_race(zone->free_area[order].nr_free));
1471	seq_putc(m, '\n');
1472}
1473
1474/*
1475 * This walks the free areas for each zone.
1476 */
1477static int frag_show(struct seq_file *m, void *arg)
1478{
1479	pg_data_t *pgdat = (pg_data_t *)arg;
1480	walk_zones_in_node(m, pgdat, true, false, frag_show_print);
1481	return 0;
1482}
1483
1484static void pagetypeinfo_showfree_print(struct seq_file *m,
1485					pg_data_t *pgdat, struct zone *zone)
1486{
1487	int order, mtype;
1488
1489	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1490		seq_printf(m, "Node %4d, zone %8s, type %12s ",
1491					pgdat->node_id,
1492					zone->name,
1493					migratetype_names[mtype]);
1494		for (order = 0; order < MAX_ORDER; ++order) {
1495			unsigned long freecount = 0;
1496			struct free_area *area;
1497			struct list_head *curr;
1498			bool overflow = false;
1499
1500			area = &(zone->free_area[order]);
1501
1502			list_for_each(curr, &area->free_list[mtype]) {
1503				/*
1504				 * Cap the free_list iteration because it might
1505				 * be really large and we are under a spinlock
1506				 * so a long time spent here could trigger a
1507				 * hard lockup detector. Anyway this is a
1508				 * debugging tool so knowing there is a handful
1509				 * of pages of this order should be more than
1510				 * sufficient.
1511				 */
1512				if (++freecount >= 100000) {
1513					overflow = true;
1514					break;
1515				}
1516			}
1517			seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
1518			spin_unlock_irq(&zone->lock);
1519			cond_resched();
1520			spin_lock_irq(&zone->lock);
1521		}
1522		seq_putc(m, '\n');
1523	}
1524}
1525
1526/* Print out the free pages at each order for each migatetype */
1527static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
1528{
1529	int order;
1530	pg_data_t *pgdat = (pg_data_t *)arg;
1531
1532	/* Print header */
1533	seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1534	for (order = 0; order < MAX_ORDER; ++order)
1535		seq_printf(m, "%6d ", order);
1536	seq_putc(m, '\n');
1537
1538	walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
 
 
1539}
1540
1541static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1542					pg_data_t *pgdat, struct zone *zone)
1543{
1544	int mtype;
1545	unsigned long pfn;
1546	unsigned long start_pfn = zone->zone_start_pfn;
1547	unsigned long end_pfn = zone_end_pfn(zone);
1548	unsigned long count[MIGRATE_TYPES] = { 0, };
1549
1550	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1551		struct page *page;
1552
1553		page = pfn_to_online_page(pfn);
1554		if (!page)
1555			continue;
1556
1557		if (page_zone(page) != zone)
1558			continue;
1559
1560		mtype = get_pageblock_migratetype(page);
1561
1562		if (mtype < MIGRATE_TYPES)
1563			count[mtype]++;
1564	}
1565
1566	/* Print counts */
1567	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1568	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1569		seq_printf(m, "%12lu ", count[mtype]);
1570	seq_putc(m, '\n');
1571}
1572
1573/* Print out the number of pageblocks for each migratetype */
1574static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1575{
1576	int mtype;
1577	pg_data_t *pgdat = (pg_data_t *)arg;
1578
1579	seq_printf(m, "\n%-23s", "Number of blocks type ");
1580	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1581		seq_printf(m, "%12s ", migratetype_names[mtype]);
1582	seq_putc(m, '\n');
1583	walk_zones_in_node(m, pgdat, true, false,
1584		pagetypeinfo_showblockcount_print);
 
 
1585}
1586
1587/*
1588 * Print out the number of pageblocks for each migratetype that contain pages
1589 * of other types. This gives an indication of how well fallbacks are being
1590 * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1591 * to determine what is going on
1592 */
1593static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1594{
1595#ifdef CONFIG_PAGE_OWNER
1596	int mtype;
1597
1598	if (!static_branch_unlikely(&page_owner_inited))
1599		return;
1600
1601	drain_all_pages(NULL);
1602
1603	seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1604	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1605		seq_printf(m, "%12s ", migratetype_names[mtype]);
1606	seq_putc(m, '\n');
1607
1608	walk_zones_in_node(m, pgdat, true, true,
1609		pagetypeinfo_showmixedcount_print);
1610#endif /* CONFIG_PAGE_OWNER */
1611}
1612
1613/*
1614 * This prints out statistics in relation to grouping pages by mobility.
1615 * It is expensive to collect so do not constantly read the file.
1616 */
1617static int pagetypeinfo_show(struct seq_file *m, void *arg)
1618{
1619	pg_data_t *pgdat = (pg_data_t *)arg;
1620
1621	/* check memoryless node */
1622	if (!node_state(pgdat->node_id, N_MEMORY))
1623		return 0;
1624
1625	seq_printf(m, "Page block order: %d\n", pageblock_order);
1626	seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
1627	seq_putc(m, '\n');
1628	pagetypeinfo_showfree(m, pgdat);
1629	pagetypeinfo_showblockcount(m, pgdat);
1630	pagetypeinfo_showmixedcount(m, pgdat);
1631
1632	return 0;
1633}
1634
1635static const struct seq_operations fragmentation_op = {
1636	.start	= frag_start,
1637	.next	= frag_next,
1638	.stop	= frag_stop,
1639	.show	= frag_show,
1640};
1641
1642static const struct seq_operations pagetypeinfo_op = {
1643	.start	= frag_start,
1644	.next	= frag_next,
1645	.stop	= frag_stop,
1646	.show	= pagetypeinfo_show,
1647};
1648
1649static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1650{
1651	int zid;
1652
1653	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1654		struct zone *compare = &pgdat->node_zones[zid];
1655
1656		if (populated_zone(compare))
1657			return zone == compare;
1658	}
1659
1660	return false;
1661}
1662
1663static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1664							struct zone *zone)
1665{
1666	int i;
1667	seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1668	if (is_zone_first_populated(pgdat, zone)) {
1669		seq_printf(m, "\n  per-node stats");
1670		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1671			unsigned long pages = node_page_state_pages(pgdat, i);
1672
1673			if (vmstat_item_print_in_thp(i))
1674				pages /= HPAGE_PMD_NR;
1675			seq_printf(m, "\n      %-12s %lu", node_stat_name(i),
1676				   pages);
1677		}
1678	}
1679	seq_printf(m,
1680		   "\n  pages free     %lu"
1681		   "\n        boost    %lu"
1682		   "\n        min      %lu"
1683		   "\n        low      %lu"
1684		   "\n        high     %lu"
1685		   "\n        spanned  %lu"
1686		   "\n        present  %lu"
1687		   "\n        managed  %lu"
1688		   "\n        cma      %lu",
1689		   zone_page_state(zone, NR_FREE_PAGES),
1690		   zone->watermark_boost,
1691		   min_wmark_pages(zone),
1692		   low_wmark_pages(zone),
1693		   high_wmark_pages(zone),
1694		   zone->spanned_pages,
1695		   zone->present_pages,
1696		   zone_managed_pages(zone),
1697		   zone_cma_pages(zone));
1698
1699	seq_printf(m,
1700		   "\n        protection: (%ld",
1701		   zone->lowmem_reserve[0]);
1702	for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1703		seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1704	seq_putc(m, ')');
1705
1706	/* If unpopulated, no other information is useful */
1707	if (!populated_zone(zone)) {
1708		seq_putc(m, '\n');
1709		return;
1710	}
1711
1712	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1713		seq_printf(m, "\n      %-12s %lu", zone_stat_name(i),
1714			   zone_page_state(zone, i));
1715
1716#ifdef CONFIG_NUMA
1717	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
1718		seq_printf(m, "\n      %-12s %lu", numa_stat_name(i),
1719			   zone_numa_event_state(zone, i));
1720#endif
1721
1722	seq_printf(m, "\n  pagesets");
1723	for_each_online_cpu(i) {
1724		struct per_cpu_pages *pcp;
1725		struct per_cpu_zonestat __maybe_unused *pzstats;
1726
1727		pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
1728		seq_printf(m,
1729			   "\n    cpu: %i"
1730			   "\n              count: %i"
1731			   "\n              high:  %i"
1732			   "\n              batch: %i",
1733			   i,
1734			   pcp->count,
1735			   pcp->high,
1736			   pcp->batch);
1737#ifdef CONFIG_SMP
1738		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
1739		seq_printf(m, "\n  vm stats threshold: %d",
1740				pzstats->stat_threshold);
1741#endif
1742	}
1743	seq_printf(m,
1744		   "\n  node_unreclaimable:  %u"
1745		   "\n  start_pfn:           %lu",
1746		   pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
1747		   zone->zone_start_pfn);
1748	seq_putc(m, '\n');
1749}
1750
1751/*
1752 * Output information about zones in @pgdat.  All zones are printed regardless
1753 * of whether they are populated or not: lowmem_reserve_ratio operates on the
1754 * set of all zones and userspace would not be aware of such zones if they are
1755 * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
1756 */
1757static int zoneinfo_show(struct seq_file *m, void *arg)
1758{
1759	pg_data_t *pgdat = (pg_data_t *)arg;
1760	walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
1761	return 0;
1762}
1763
1764static const struct seq_operations zoneinfo_op = {
1765	.start	= frag_start, /* iterate over all zones. The same as in
1766			       * fragmentation. */
1767	.next	= frag_next,
1768	.stop	= frag_stop,
1769	.show	= zoneinfo_show,
1770};
1771
1772#define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
1773			 NR_VM_NUMA_EVENT_ITEMS + \
1774			 NR_VM_NODE_STAT_ITEMS + \
1775			 NR_VM_WRITEBACK_STAT_ITEMS + \
1776			 (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
1777			  NR_VM_EVENT_ITEMS : 0))
1778
1779static void *vmstat_start(struct seq_file *m, loff_t *pos)
1780{
1781	unsigned long *v;
1782	int i;
1783
1784	if (*pos >= NR_VMSTAT_ITEMS)
1785		return NULL;
1786
1787	BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
1788	fold_vm_numa_events();
1789	v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
1790	m->private = v;
1791	if (!v)
1792		return ERR_PTR(-ENOMEM);
1793	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1794		v[i] = global_zone_page_state(i);
1795	v += NR_VM_ZONE_STAT_ITEMS;
1796
1797#ifdef CONFIG_NUMA
1798	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
1799		v[i] = global_numa_event_state(i);
1800	v += NR_VM_NUMA_EVENT_ITEMS;
1801#endif
1802
1803	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1804		v[i] = global_node_page_state_pages(i);
1805		if (vmstat_item_print_in_thp(i))
1806			v[i] /= HPAGE_PMD_NR;
1807	}
1808	v += NR_VM_NODE_STAT_ITEMS;
1809
1810	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1811			    v + NR_DIRTY_THRESHOLD);
1812	v += NR_VM_WRITEBACK_STAT_ITEMS;
1813
1814#ifdef CONFIG_VM_EVENT_COUNTERS
1815	all_vm_events(v);
1816	v[PGPGIN] /= 2;		/* sectors -> kbytes */
1817	v[PGPGOUT] /= 2;
1818#endif
1819	return (unsigned long *)m->private + *pos;
1820}
1821
1822static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1823{
1824	(*pos)++;
1825	if (*pos >= NR_VMSTAT_ITEMS)
1826		return NULL;
1827	return (unsigned long *)m->private + *pos;
1828}
1829
1830static int vmstat_show(struct seq_file *m, void *arg)
1831{
1832	unsigned long *l = arg;
1833	unsigned long off = l - (unsigned long *)m->private;
1834
1835	seq_puts(m, vmstat_text[off]);
1836	seq_put_decimal_ull(m, " ", *l);
1837	seq_putc(m, '\n');
1838
1839	if (off == NR_VMSTAT_ITEMS - 1) {
1840		/*
1841		 * We've come to the end - add any deprecated counters to avoid
1842		 * breaking userspace which might depend on them being present.
1843		 */
1844		seq_puts(m, "nr_unstable 0\n");
1845	}
1846	return 0;
1847}
1848
1849static void vmstat_stop(struct seq_file *m, void *arg)
1850{
1851	kfree(m->private);
1852	m->private = NULL;
1853}
1854
1855static const struct seq_operations vmstat_op = {
1856	.start	= vmstat_start,
1857	.next	= vmstat_next,
1858	.stop	= vmstat_stop,
1859	.show	= vmstat_show,
1860};
1861#endif /* CONFIG_PROC_FS */
1862
1863#ifdef CONFIG_SMP
1864static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1865int sysctl_stat_interval __read_mostly = HZ;
1866
1867#ifdef CONFIG_PROC_FS
1868static void refresh_vm_stats(struct work_struct *work)
1869{
1870	refresh_cpu_vm_stats(true);
1871}
1872
1873int vmstat_refresh(struct ctl_table *table, int write,
1874		   void *buffer, size_t *lenp, loff_t *ppos)
1875{
1876	long val;
1877	int err;
1878	int i;
1879
1880	/*
1881	 * The regular update, every sysctl_stat_interval, may come later
1882	 * than expected: leaving a significant amount in per_cpu buckets.
1883	 * This is particularly misleading when checking a quantity of HUGE
1884	 * pages, immediately after running a test.  /proc/sys/vm/stat_refresh,
1885	 * which can equally be echo'ed to or cat'ted from (by root),
1886	 * can be used to update the stats just before reading them.
1887	 *
1888	 * Oh, and since global_zone_page_state() etc. are so careful to hide
1889	 * transiently negative values, report an error here if any of
1890	 * the stats is negative, so we know to go looking for imbalance.
1891	 */
1892	err = schedule_on_each_cpu(refresh_vm_stats);
1893	if (err)
1894		return err;
1895	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1896		/*
1897		 * Skip checking stats known to go negative occasionally.
1898		 */
1899		switch (i) {
1900		case NR_ZONE_WRITE_PENDING:
1901		case NR_FREE_CMA_PAGES:
1902			continue;
1903		}
1904		val = atomic_long_read(&vm_zone_stat[i]);
1905		if (val < 0) {
1906			pr_warn("%s: %s %ld\n",
1907				__func__, zone_stat_name(i), val);
1908		}
1909	}
1910	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1911		/*
1912		 * Skip checking stats known to go negative occasionally.
1913		 */
1914		switch (i) {
1915		case NR_WRITEBACK:
1916			continue;
1917		}
1918		val = atomic_long_read(&vm_node_stat[i]);
1919		if (val < 0) {
1920			pr_warn("%s: %s %ld\n",
1921				__func__, node_stat_name(i), val);
1922		}
1923	}
1924	if (write)
1925		*ppos += *lenp;
1926	else
1927		*lenp = 0;
1928	return 0;
1929}
1930#endif /* CONFIG_PROC_FS */
1931
1932static void vmstat_update(struct work_struct *w)
1933{
1934	if (refresh_cpu_vm_stats(true)) {
1935		/*
1936		 * Counters were updated so we expect more updates
1937		 * to occur in the future. Keep on running the
1938		 * update worker thread.
1939		 */
1940		queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
1941				this_cpu_ptr(&vmstat_work),
1942				round_jiffies_relative(sysctl_stat_interval));
1943	}
1944}
1945
1946/*
 
 
 
 
 
1947 * Check if the diffs for a certain cpu indicate that
1948 * an update is needed.
1949 */
1950static bool need_update(int cpu)
1951{
1952	pg_data_t *last_pgdat = NULL;
1953	struct zone *zone;
1954
1955	for_each_populated_zone(zone) {
1956		struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
1957		struct per_cpu_nodestat *n;
1958
1959		/*
1960		 * The fast way of checking if there are any vmstat diffs.
1961		 */
1962		if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
 
1963			return true;
1964
1965		if (last_pgdat == zone->zone_pgdat)
1966			continue;
1967		last_pgdat = zone->zone_pgdat;
1968		n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
1969		if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
1970			return true;
 
1971	}
1972	return false;
1973}
1974
1975/*
1976 * Switch off vmstat processing and then fold all the remaining differentials
1977 * until the diffs stay at zero. The function is used by NOHZ and can only be
1978 * invoked when tick processing is not active.
1979 */
1980void quiet_vmstat(void)
1981{
1982	if (system_state != SYSTEM_RUNNING)
1983		return;
1984
1985	if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
1986		return;
1987
1988	if (!need_update(smp_processor_id()))
1989		return;
1990
1991	/*
1992	 * Just refresh counters and do not care about the pending delayed
1993	 * vmstat_update. It doesn't fire that often to matter and canceling
1994	 * it would be too expensive from this path.
1995	 * vmstat_shepherd will take care about that for us.
1996	 */
1997	refresh_cpu_vm_stats(false);
1998}
1999
2000/*
2001 * Shepherd worker thread that checks the
2002 * differentials of processors that have their worker
2003 * threads for vm statistics updates disabled because of
2004 * inactivity.
2005 */
2006static void vmstat_shepherd(struct work_struct *w);
2007
2008static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
2009
2010static void vmstat_shepherd(struct work_struct *w)
2011{
2012	int cpu;
2013
2014	cpus_read_lock();
2015	/* Check processors whose vmstat worker threads have been disabled */
2016	for_each_online_cpu(cpu) {
2017		struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
2018
2019		if (!delayed_work_pending(dw) && need_update(cpu))
2020			queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
2021
2022		cond_resched();
2023	}
2024	cpus_read_unlock();
2025
2026	schedule_delayed_work(&shepherd,
2027		round_jiffies_relative(sysctl_stat_interval));
2028}
2029
2030static void __init start_shepherd_timer(void)
2031{
2032	int cpu;
2033
2034	for_each_possible_cpu(cpu)
2035		INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
2036			vmstat_update);
2037
2038	schedule_delayed_work(&shepherd,
2039		round_jiffies_relative(sysctl_stat_interval));
2040}
2041
2042static void __init init_cpu_node_state(void)
2043{
2044	int node;
2045
2046	for_each_online_node(node) {
2047		if (!cpumask_empty(cpumask_of_node(node)))
2048			node_set_state(node, N_CPU);
2049	}
2050}
2051
2052static int vmstat_cpu_online(unsigned int cpu)
2053{
2054	refresh_zone_stat_thresholds();
2055
2056	if (!node_state(cpu_to_node(cpu), N_CPU)) {
2057		node_set_state(cpu_to_node(cpu), N_CPU);
2058	}
2059
2060	return 0;
2061}
2062
2063static int vmstat_cpu_down_prep(unsigned int cpu)
2064{
2065	cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
2066	return 0;
2067}
2068
2069static int vmstat_cpu_dead(unsigned int cpu)
2070{
2071	const struct cpumask *node_cpus;
2072	int node;
2073
2074	node = cpu_to_node(cpu);
2075
2076	refresh_zone_stat_thresholds();
2077	node_cpus = cpumask_of_node(node);
2078	if (!cpumask_empty(node_cpus))
2079		return 0;
2080
2081	node_clear_state(node, N_CPU);
2082
2083	return 0;
2084}
2085
2086#endif
2087
2088struct workqueue_struct *mm_percpu_wq;
2089
2090void __init init_mm_internals(void)
2091{
2092	int ret __maybe_unused;
2093
2094	mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
2095
2096#ifdef CONFIG_SMP
2097	ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
2098					NULL, vmstat_cpu_dead);
2099	if (ret < 0)
2100		pr_err("vmstat: failed to register 'dead' hotplug state\n");
2101
2102	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
2103					vmstat_cpu_online,
2104					vmstat_cpu_down_prep);
2105	if (ret < 0)
2106		pr_err("vmstat: failed to register 'online' hotplug state\n");
2107
2108	cpus_read_lock();
2109	init_cpu_node_state();
2110	cpus_read_unlock();
2111
2112	start_shepherd_timer();
2113#endif
2114#ifdef CONFIG_PROC_FS
2115	proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
2116	proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
2117	proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
2118	proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
2119#endif
2120}
2121
2122#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
2123
2124/*
2125 * Return an index indicating how much of the available free memory is
2126 * unusable for an allocation of the requested size.
2127 */
2128static int unusable_free_index(unsigned int order,
2129				struct contig_page_info *info)
2130{
2131	/* No free memory is interpreted as all free memory is unusable */
2132	if (info->free_pages == 0)
2133		return 1000;
2134
2135	/*
2136	 * Index should be a value between 0 and 1. Return a value to 3
2137	 * decimal places.
2138	 *
2139	 * 0 => no fragmentation
2140	 * 1 => high fragmentation
2141	 */
2142	return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
2143
2144}
2145
2146static void unusable_show_print(struct seq_file *m,
2147					pg_data_t *pgdat, struct zone *zone)
2148{
2149	unsigned int order;
2150	int index;
2151	struct contig_page_info info;
2152
2153	seq_printf(m, "Node %d, zone %8s ",
2154				pgdat->node_id,
2155				zone->name);
2156	for (order = 0; order < MAX_ORDER; ++order) {
2157		fill_contig_page_info(zone, order, &info);
2158		index = unusable_free_index(order, &info);
2159		seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2160	}
2161
2162	seq_putc(m, '\n');
2163}
2164
2165/*
2166 * Display unusable free space index
2167 *
2168 * The unusable free space index measures how much of the available free
2169 * memory cannot be used to satisfy an allocation of a given size and is a
2170 * value between 0 and 1. The higher the value, the more of free memory is
2171 * unusable and by implication, the worse the external fragmentation is. This
2172 * can be expressed as a percentage by multiplying by 100.
2173 */
2174static int unusable_show(struct seq_file *m, void *arg)
2175{
2176	pg_data_t *pgdat = (pg_data_t *)arg;
2177
2178	/* check memoryless node */
2179	if (!node_state(pgdat->node_id, N_MEMORY))
2180		return 0;
2181
2182	walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
2183
2184	return 0;
2185}
2186
2187static const struct seq_operations unusable_sops = {
2188	.start	= frag_start,
2189	.next	= frag_next,
2190	.stop	= frag_stop,
2191	.show	= unusable_show,
2192};
2193
2194DEFINE_SEQ_ATTRIBUTE(unusable);
2195
2196static void extfrag_show_print(struct seq_file *m,
2197					pg_data_t *pgdat, struct zone *zone)
2198{
2199	unsigned int order;
2200	int index;
2201
2202	/* Alloc on stack as interrupts are disabled for zone walk */
2203	struct contig_page_info info;
2204
2205	seq_printf(m, "Node %d, zone %8s ",
2206				pgdat->node_id,
2207				zone->name);
2208	for (order = 0; order < MAX_ORDER; ++order) {
2209		fill_contig_page_info(zone, order, &info);
2210		index = __fragmentation_index(order, &info);
2211		seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
2212	}
2213
2214	seq_putc(m, '\n');
2215}
2216
2217/*
2218 * Display fragmentation index for orders that allocations would fail for
2219 */
2220static int extfrag_show(struct seq_file *m, void *arg)
2221{
2222	pg_data_t *pgdat = (pg_data_t *)arg;
2223
2224	walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
2225
2226	return 0;
2227}
2228
2229static const struct seq_operations extfrag_sops = {
2230	.start	= frag_start,
2231	.next	= frag_next,
2232	.stop	= frag_stop,
2233	.show	= extfrag_show,
2234};
2235
2236DEFINE_SEQ_ATTRIBUTE(extfrag);
2237
2238static int __init extfrag_debug_init(void)
2239{
2240	struct dentry *extfrag_debug_root;
2241
2242	extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
2243
2244	debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
2245			    &unusable_fops);
2246
2247	debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
2248			    &extfrag_fops);
2249
2250	return 0;
2251}
2252
2253module_init(extfrag_debug_init);
2254#endif