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