Linux Audio

Check our new training course

Loading...
v5.9
   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#define NUMA_STATS_THRESHOLD (U16_MAX - 2)
  35
  36#ifdef CONFIG_NUMA
  37int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
  38
  39/* zero numa counters within a zone */
  40static void zero_zone_numa_counters(struct zone *zone)
  41{
  42	int item, cpu;
  43
  44	for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++) {
  45		atomic_long_set(&zone->vm_numa_stat[item], 0);
  46		for_each_online_cpu(cpu)
  47			per_cpu_ptr(zone->pageset, cpu)->vm_numa_stat_diff[item]
  48						= 0;
  49	}
  50}
  51
  52/* zero numa counters of all the populated zones */
  53static void zero_zones_numa_counters(void)
  54{
  55	struct zone *zone;
  56
  57	for_each_populated_zone(zone)
  58		zero_zone_numa_counters(zone);
  59}
  60
  61/* zero global numa counters */
  62static void zero_global_numa_counters(void)
  63{
  64	int item;
  65
  66	for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++)
  67		atomic_long_set(&vm_numa_stat[item], 0);
  68}
  69
  70static void invalid_numa_statistics(void)
  71{
  72	zero_zones_numa_counters();
  73	zero_global_numa_counters();
  74}
  75
  76static DEFINE_MUTEX(vm_numa_stat_lock);
  77
  78int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
  79		void *buffer, size_t *length, loff_t *ppos)
  80{
  81	int ret, oldval;
  82
  83	mutex_lock(&vm_numa_stat_lock);
  84	if (write)
  85		oldval = sysctl_vm_numa_stat;
  86	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
  87	if (ret || !write)
  88		goto out;
  89
  90	if (oldval == sysctl_vm_numa_stat)
  91		goto out;
  92	else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
  93		static_branch_enable(&vm_numa_stat_key);
  94		pr_info("enable numa statistics\n");
  95	} else {
  96		static_branch_disable(&vm_numa_stat_key);
  97		invalid_numa_statistics();
  98		pr_info("disable numa statistics, and clear numa counters\n");
  99	}
 100
 101out:
 102	mutex_unlock(&vm_numa_stat_lock);
 103	return ret;
 104}
 105#endif
 106
 107#ifdef CONFIG_VM_EVENT_COUNTERS
 108DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
 109EXPORT_PER_CPU_SYMBOL(vm_event_states);
 110
 111static void sum_vm_events(unsigned long *ret)
 112{
 113	int cpu;
 114	int i;
 115
 116	memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
 117
 118	for_each_online_cpu(cpu) {
 119		struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
 120
 121		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
 122			ret[i] += this->event[i];
 123	}
 124}
 125
 126/*
 127 * Accumulate the vm event counters across all CPUs.
 128 * The result is unavoidably approximate - it can change
 129 * during and after execution of this function.
 130*/
 131void all_vm_events(unsigned long *ret)
 132{
 133	get_online_cpus();
 134	sum_vm_events(ret);
 135	put_online_cpus();
 136}
 137EXPORT_SYMBOL_GPL(all_vm_events);
 138
 139/*
 140 * Fold the foreign cpu events into our own.
 141 *
 142 * This is adding to the events on one processor
 143 * but keeps the global counts constant.
 144 */
 145void vm_events_fold_cpu(int cpu)
 146{
 147	struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
 148	int i;
 149
 150	for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
 151		count_vm_events(i, fold_state->event[i]);
 152		fold_state->event[i] = 0;
 153	}
 154}
 155
 156#endif /* CONFIG_VM_EVENT_COUNTERS */
 157
 158/*
 159 * Manage combined zone based / global counters
 160 *
 161 * vm_stat contains the global counters
 162 */
 163atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
 164atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS] __cacheline_aligned_in_smp;
 165atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
 166EXPORT_SYMBOL(vm_zone_stat);
 167EXPORT_SYMBOL(vm_numa_stat);
 168EXPORT_SYMBOL(vm_node_stat);
 169
 170#ifdef CONFIG_SMP
 171
 172int calculate_pressure_threshold(struct zone *zone)
 173{
 174	int threshold;
 175	int watermark_distance;
 176
 177	/*
 178	 * As vmstats are not up to date, there is drift between the estimated
 179	 * and real values. For high thresholds and a high number of CPUs, it
 180	 * is possible for the min watermark to be breached while the estimated
 181	 * value looks fine. The pressure threshold is a reduced value such
 182	 * that even the maximum amount of drift will not accidentally breach
 183	 * the min watermark
 184	 */
 185	watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
 186	threshold = max(1, (int)(watermark_distance / num_online_cpus()));
 187
 188	/*
 189	 * Maximum threshold is 125
 190	 */
 191	threshold = min(125, threshold);
 192
 193	return threshold;
 194}
 195
 196int calculate_normal_threshold(struct zone *zone)
 197{
 198	int threshold;
 199	int mem;	/* memory in 128 MB units */
 200
 201	/*
 202	 * The threshold scales with the number of processors and the amount
 203	 * of memory per zone. More memory means that we can defer updates for
 204	 * longer, more processors could lead to more contention.
 205 	 * fls() is used to have a cheap way of logarithmic scaling.
 206	 *
 207	 * Some sample thresholds:
 208	 *
 209	 * Threshold	Processors	(fls)	Zonesize	fls(mem+1)
 210	 * ------------------------------------------------------------------
 211	 * 8		1		1	0.9-1 GB	4
 212	 * 16		2		2	0.9-1 GB	4
 213	 * 20 		2		2	1-2 GB		5
 214	 * 24		2		2	2-4 GB		6
 215	 * 28		2		2	4-8 GB		7
 216	 * 32		2		2	8-16 GB		8
 217	 * 4		2		2	<128M		1
 218	 * 30		4		3	2-4 GB		5
 219	 * 48		4		3	8-16 GB		8
 220	 * 32		8		4	1-2 GB		4
 221	 * 32		8		4	0.9-1GB		4
 222	 * 10		16		5	<128M		1
 223	 * 40		16		5	900M		4
 224	 * 70		64		7	2-4 GB		5
 225	 * 84		64		7	4-8 GB		6
 226	 * 108		512		9	4-8 GB		6
 227	 * 125		1024		10	8-16 GB		8
 228	 * 125		1024		10	16-32 GB	9
 229	 */
 230
 231	mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
 232
 233	threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 234
 235	/*
 236	 * Maximum threshold is 125
 237	 */
 238	threshold = min(125, threshold);
 239
 240	return threshold;
 241}
 242
 243/*
 244 * Refresh the thresholds for each zone.
 245 */
 246void refresh_zone_stat_thresholds(void)
 247{
 248	struct pglist_data *pgdat;
 249	struct zone *zone;
 250	int cpu;
 251	int threshold;
 252
 253	/* Zero current pgdat thresholds */
 254	for_each_online_pgdat(pgdat) {
 255		for_each_online_cpu(cpu) {
 256			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
 257		}
 258	}
 259
 260	for_each_populated_zone(zone) {
 261		struct pglist_data *pgdat = zone->zone_pgdat;
 262		unsigned long max_drift, tolerate_drift;
 263
 264		threshold = calculate_normal_threshold(zone);
 265
 266		for_each_online_cpu(cpu) {
 267			int pgdat_threshold;
 268
 269			per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 270							= threshold;
 271
 272			/* Base nodestat threshold on the largest populated zone. */
 273			pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
 274			per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
 275				= max(threshold, pgdat_threshold);
 276		}
 277
 278		/*
 279		 * Only set percpu_drift_mark if there is a danger that
 280		 * NR_FREE_PAGES reports the low watermark is ok when in fact
 281		 * the min watermark could be breached by an allocation
 282		 */
 283		tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 284		max_drift = num_online_cpus() * threshold;
 285		if (max_drift > tolerate_drift)
 286			zone->percpu_drift_mark = high_wmark_pages(zone) +
 287					max_drift;
 288	}
 289}
 290
 291void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 292				int (*calculate_pressure)(struct zone *))
 293{
 294	struct zone *zone;
 295	int cpu;
 296	int threshold;
 297	int i;
 298
 299	for (i = 0; i < pgdat->nr_zones; i++) {
 300		zone = &pgdat->node_zones[i];
 301		if (!zone->percpu_drift_mark)
 302			continue;
 303
 304		threshold = (*calculate_pressure)(zone);
 305		for_each_online_cpu(cpu)
 306			per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 307							= threshold;
 308	}
 309}
 310
 311/*
 312 * For use when we know that interrupts are disabled,
 313 * or when we know that preemption is disabled and that
 314 * particular counter cannot be updated from interrupt context.
 315 */
 316void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 317			   long delta)
 318{
 319	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 320	s8 __percpu *p = pcp->vm_stat_diff + item;
 321	long x;
 322	long t;
 323
 324	x = delta + __this_cpu_read(*p);
 325
 326	t = __this_cpu_read(pcp->stat_threshold);
 327
 328	if (unlikely(x > t || x < -t)) {
 329		zone_page_state_add(x, zone, item);
 330		x = 0;
 331	}
 332	__this_cpu_write(*p, x);
 333}
 334EXPORT_SYMBOL(__mod_zone_page_state);
 335
 336void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 337				long delta)
 338{
 339	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 340	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 341	long x;
 342	long t;
 343
 344	if (vmstat_item_in_bytes(item)) {
 345		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
 346		delta >>= PAGE_SHIFT;
 347	}
 348
 349	x = delta + __this_cpu_read(*p);
 350
 351	t = __this_cpu_read(pcp->stat_threshold);
 352
 353	if (unlikely(x > t || x < -t)) {
 354		node_page_state_add(x, pgdat, item);
 355		x = 0;
 356	}
 357	__this_cpu_write(*p, x);
 358}
 359EXPORT_SYMBOL(__mod_node_page_state);
 360
 361/*
 362 * Optimized increment and decrement functions.
 363 *
 364 * These are only for a single page and therefore can take a struct page *
 365 * argument instead of struct zone *. This allows the inclusion of the code
 366 * generated for page_zone(page) into the optimized functions.
 367 *
 368 * No overflow check is necessary and therefore the differential can be
 369 * incremented or decremented in place which may allow the compilers to
 370 * generate better code.
 371 * The increment or decrement is known and therefore one boundary check can
 372 * be omitted.
 373 *
 374 * NOTE: These functions are very performance sensitive. Change only
 375 * with care.
 376 *
 377 * Some processors have inc/dec instructions that are atomic vs an interrupt.
 378 * However, the code must first determine the differential location in a zone
 379 * based on the processor number and then inc/dec the counter. There is no
 380 * guarantee without disabling preemption that the processor will not change
 381 * in between and therefore the atomicity vs. interrupt cannot be exploited
 382 * in a useful way here.
 383 */
 384void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 385{
 386	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 387	s8 __percpu *p = pcp->vm_stat_diff + item;
 388	s8 v, t;
 389
 390	v = __this_cpu_inc_return(*p);
 391	t = __this_cpu_read(pcp->stat_threshold);
 392	if (unlikely(v > t)) {
 393		s8 overstep = t >> 1;
 394
 395		zone_page_state_add(v + overstep, zone, item);
 396		__this_cpu_write(*p, -overstep);
 397	}
 398}
 399
 400void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 401{
 402	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 403	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 404	s8 v, t;
 405
 406	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 407
 408	v = __this_cpu_inc_return(*p);
 409	t = __this_cpu_read(pcp->stat_threshold);
 410	if (unlikely(v > t)) {
 411		s8 overstep = t >> 1;
 412
 413		node_page_state_add(v + overstep, pgdat, item);
 414		__this_cpu_write(*p, -overstep);
 415	}
 416}
 417
 418void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 419{
 420	__inc_zone_state(page_zone(page), item);
 421}
 422EXPORT_SYMBOL(__inc_zone_page_state);
 423
 424void __inc_node_page_state(struct page *page, enum node_stat_item item)
 425{
 426	__inc_node_state(page_pgdat(page), item);
 427}
 428EXPORT_SYMBOL(__inc_node_page_state);
 429
 430void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 431{
 432	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 433	s8 __percpu *p = pcp->vm_stat_diff + item;
 434	s8 v, t;
 435
 436	v = __this_cpu_dec_return(*p);
 437	t = __this_cpu_read(pcp->stat_threshold);
 438	if (unlikely(v < - t)) {
 439		s8 overstep = t >> 1;
 440
 441		zone_page_state_add(v - overstep, zone, item);
 442		__this_cpu_write(*p, overstep);
 443	}
 444}
 445
 446void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 447{
 448	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 449	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 450	s8 v, t;
 451
 452	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 453
 454	v = __this_cpu_dec_return(*p);
 455	t = __this_cpu_read(pcp->stat_threshold);
 456	if (unlikely(v < - t)) {
 457		s8 overstep = t >> 1;
 458
 459		node_page_state_add(v - overstep, pgdat, item);
 460		__this_cpu_write(*p, overstep);
 461	}
 462}
 463
 464void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 465{
 466	__dec_zone_state(page_zone(page), item);
 467}
 468EXPORT_SYMBOL(__dec_zone_page_state);
 469
 470void __dec_node_page_state(struct page *page, enum node_stat_item item)
 471{
 472	__dec_node_state(page_pgdat(page), item);
 473}
 474EXPORT_SYMBOL(__dec_node_page_state);
 475
 476#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 477/*
 478 * If we have cmpxchg_local support then we do not need to incur the overhead
 479 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 480 *
 481 * mod_state() modifies the zone counter state through atomic per cpu
 482 * operations.
 483 *
 484 * Overstep mode specifies how overstep should handled:
 485 *     0       No overstepping
 486 *     1       Overstepping half of threshold
 487 *     -1      Overstepping minus half of threshold
 488*/
 489static inline void mod_zone_state(struct zone *zone,
 490       enum zone_stat_item item, long delta, int overstep_mode)
 491{
 492	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 493	s8 __percpu *p = pcp->vm_stat_diff + item;
 494	long o, n, t, z;
 495
 496	do {
 497		z = 0;  /* overflow to zone counters */
 498
 499		/*
 500		 * The fetching of the stat_threshold is racy. We may apply
 501		 * a counter threshold to the wrong the cpu if we get
 502		 * rescheduled while executing here. However, the next
 503		 * counter update will apply the threshold again and
 504		 * therefore bring the counter under the threshold again.
 505		 *
 506		 * Most of the time the thresholds are the same anyways
 507		 * for all cpus in a zone.
 508		 */
 509		t = this_cpu_read(pcp->stat_threshold);
 510
 511		o = this_cpu_read(*p);
 512		n = delta + o;
 513
 514		if (n > t || n < -t) {
 515			int os = overstep_mode * (t >> 1) ;
 516
 517			/* Overflow must be added to zone counters */
 518			z = n + os;
 519			n = -os;
 520		}
 521	} while (this_cpu_cmpxchg(*p, o, n) != o);
 522
 523	if (z)
 524		zone_page_state_add(z, zone, item);
 525}
 526
 527void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 528			 long delta)
 529{
 530	mod_zone_state(zone, item, delta, 0);
 531}
 532EXPORT_SYMBOL(mod_zone_page_state);
 533
 
 
 
 
 
 534void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 535{
 536	mod_zone_state(page_zone(page), item, 1, 1);
 537}
 538EXPORT_SYMBOL(inc_zone_page_state);
 539
 540void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 541{
 542	mod_zone_state(page_zone(page), item, -1, -1);
 543}
 544EXPORT_SYMBOL(dec_zone_page_state);
 545
 546static inline void mod_node_state(struct pglist_data *pgdat,
 547       enum node_stat_item item, int delta, int overstep_mode)
 548{
 549	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 550	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 551	long o, n, t, z;
 552
 553	if (vmstat_item_in_bytes(item)) {
 554		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
 555		delta >>= PAGE_SHIFT;
 556	}
 557
 558	do {
 559		z = 0;  /* overflow to node counters */
 560
 561		/*
 562		 * The fetching of the stat_threshold is racy. We may apply
 563		 * a counter threshold to the wrong the cpu if we get
 564		 * rescheduled while executing here. However, the next
 565		 * counter update will apply the threshold again and
 566		 * therefore bring the counter under the threshold again.
 567		 *
 568		 * Most of the time the thresholds are the same anyways
 569		 * for all cpus in a node.
 570		 */
 571		t = this_cpu_read(pcp->stat_threshold);
 572
 573		o = this_cpu_read(*p);
 574		n = delta + o;
 575
 576		if (n > t || n < -t) {
 577			int os = overstep_mode * (t >> 1) ;
 578
 579			/* Overflow must be added to node counters */
 580			z = n + os;
 581			n = -os;
 582		}
 583	} while (this_cpu_cmpxchg(*p, o, n) != o);
 584
 585	if (z)
 586		node_page_state_add(z, pgdat, item);
 587}
 588
 589void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 590					long delta)
 591{
 592	mod_node_state(pgdat, item, delta, 0);
 593}
 594EXPORT_SYMBOL(mod_node_page_state);
 595
 596void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 597{
 598	mod_node_state(pgdat, item, 1, 1);
 599}
 600
 601void inc_node_page_state(struct page *page, enum node_stat_item item)
 602{
 603	mod_node_state(page_pgdat(page), item, 1, 1);
 604}
 605EXPORT_SYMBOL(inc_node_page_state);
 606
 607void dec_node_page_state(struct page *page, enum node_stat_item item)
 608{
 609	mod_node_state(page_pgdat(page), item, -1, -1);
 610}
 611EXPORT_SYMBOL(dec_node_page_state);
 612#else
 613/*
 614 * Use interrupt disable to serialize counter updates
 615 */
 616void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 617			 long delta)
 618{
 619	unsigned long flags;
 620
 621	local_irq_save(flags);
 622	__mod_zone_page_state(zone, item, delta);
 623	local_irq_restore(flags);
 624}
 625EXPORT_SYMBOL(mod_zone_page_state);
 626
 627void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 628{
 629	unsigned long flags;
 630	struct zone *zone;
 631
 632	zone = page_zone(page);
 633	local_irq_save(flags);
 634	__inc_zone_state(zone, item);
 635	local_irq_restore(flags);
 636}
 637EXPORT_SYMBOL(inc_zone_page_state);
 638
 639void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 640{
 641	unsigned long flags;
 642
 643	local_irq_save(flags);
 644	__dec_zone_page_state(page, item);
 645	local_irq_restore(flags);
 646}
 647EXPORT_SYMBOL(dec_zone_page_state);
 648
 649void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 650{
 651	unsigned long flags;
 652
 653	local_irq_save(flags);
 654	__inc_node_state(pgdat, item);
 655	local_irq_restore(flags);
 656}
 657EXPORT_SYMBOL(inc_node_state);
 658
 659void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 660					long delta)
 661{
 662	unsigned long flags;
 663
 664	local_irq_save(flags);
 665	__mod_node_page_state(pgdat, item, delta);
 666	local_irq_restore(flags);
 667}
 668EXPORT_SYMBOL(mod_node_page_state);
 669
 670void inc_node_page_state(struct page *page, enum node_stat_item item)
 671{
 672	unsigned long flags;
 673	struct pglist_data *pgdat;
 674
 675	pgdat = page_pgdat(page);
 676	local_irq_save(flags);
 677	__inc_node_state(pgdat, item);
 678	local_irq_restore(flags);
 679}
 680EXPORT_SYMBOL(inc_node_page_state);
 681
 682void dec_node_page_state(struct page *page, enum node_stat_item item)
 683{
 684	unsigned long flags;
 685
 686	local_irq_save(flags);
 687	__dec_node_page_state(page, item);
 688	local_irq_restore(flags);
 689}
 690EXPORT_SYMBOL(dec_node_page_state);
 691#endif
 692
 
 693/*
 694 * Fold a differential into the global counters.
 695 * Returns the number of counters updated.
 696 */
 697#ifdef CONFIG_NUMA
 698static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
 699{
 700	int i;
 701	int changes = 0;
 702
 703	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 704		if (zone_diff[i]) {
 705			atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
 706			changes++;
 707	}
 708
 709	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 710		if (numa_diff[i]) {
 711			atomic_long_add(numa_diff[i], &vm_numa_stat[i]);
 712			changes++;
 713	}
 714
 715	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 716		if (node_diff[i]) {
 717			atomic_long_add(node_diff[i], &vm_node_stat[i]);
 718			changes++;
 719	}
 720	return changes;
 721}
 722#else
 723static int fold_diff(int *zone_diff, int *node_diff)
 724{
 725	int i;
 726	int changes = 0;
 727
 728	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 729		if (zone_diff[i]) {
 730			atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
 731			changes++;
 732	}
 733
 734	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 735		if (node_diff[i]) {
 736			atomic_long_add(node_diff[i], &vm_node_stat[i]);
 737			changes++;
 738	}
 739	return changes;
 740}
 741#endif /* CONFIG_NUMA */
 742
 743/*
 744 * Update the zone counters for the current cpu.
 745 *
 746 * Note that refresh_cpu_vm_stats strives to only access
 747 * node local memory. The per cpu pagesets on remote zones are placed
 748 * in the memory local to the processor using that pageset. So the
 749 * loop over all zones will access a series of cachelines local to
 750 * the processor.
 751 *
 752 * The call to zone_page_state_add updates the cachelines with the
 753 * statistics in the remote zone struct as well as the global cachelines
 754 * with the global counters. These could cause remote node cache line
 755 * bouncing and will have to be only done when necessary.
 756 *
 757 * The function returns the number of global counters updated.
 758 */
 759static int refresh_cpu_vm_stats(bool do_pagesets)
 760{
 761	struct pglist_data *pgdat;
 762	struct zone *zone;
 763	int i;
 764	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 765#ifdef CONFIG_NUMA
 766	int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
 767#endif
 768	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 769	int changes = 0;
 770
 771	for_each_populated_zone(zone) {
 772		struct per_cpu_pageset __percpu *p = zone->pageset;
 773
 774		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 775			int v;
 776
 777			v = this_cpu_xchg(p->vm_stat_diff[i], 0);
 778			if (v) {
 779
 780				atomic_long_add(v, &zone->vm_stat[i]);
 781				global_zone_diff[i] += v;
 782#ifdef CONFIG_NUMA
 783				/* 3 seconds idle till flush */
 784				__this_cpu_write(p->expire, 3);
 785#endif
 786			}
 787		}
 788#ifdef CONFIG_NUMA
 789		for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
 790			int v;
 791
 792			v = this_cpu_xchg(p->vm_numa_stat_diff[i], 0);
 793			if (v) {
 794
 795				atomic_long_add(v, &zone->vm_numa_stat[i]);
 796				global_numa_diff[i] += v;
 797				__this_cpu_write(p->expire, 3);
 798			}
 799		}
 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(p->expire) ||
 811			       !__this_cpu_read(p->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(p->expire, 0);
 819				continue;
 820			}
 821
 822			if (__this_cpu_dec_return(p->expire))
 823				continue;
 824
 825			if (__this_cpu_read(p->pcp.count)) {
 826				drain_zone_pages(zone, this_cpu_ptr(&p->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#ifdef CONFIG_NUMA
 848	changes += fold_diff(global_zone_diff, global_numa_diff,
 849			     global_node_diff);
 850#else
 851	changes += fold_diff(global_zone_diff, global_node_diff);
 852#endif
 853	return changes;
 854}
 855
 856/*
 857 * Fold the data for an offline cpu into the global array.
 858 * There cannot be any access by the offline cpu and therefore
 859 * synchronization is simplified.
 860 */
 861void cpu_vm_stats_fold(int cpu)
 862{
 863	struct pglist_data *pgdat;
 864	struct zone *zone;
 865	int i;
 866	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 867#ifdef CONFIG_NUMA
 868	int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
 869#endif
 870	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 871
 872	for_each_populated_zone(zone) {
 873		struct per_cpu_pageset *p;
 874
 875		p = per_cpu_ptr(zone->pageset, cpu);
 876
 877		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 878			if (p->vm_stat_diff[i]) {
 879				int v;
 880
 881				v = p->vm_stat_diff[i];
 882				p->vm_stat_diff[i] = 0;
 883				atomic_long_add(v, &zone->vm_stat[i]);
 884				global_zone_diff[i] += v;
 885			}
 886
 887#ifdef CONFIG_NUMA
 888		for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 889			if (p->vm_numa_stat_diff[i]) {
 890				int v;
 891
 892				v = p->vm_numa_stat_diff[i];
 893				p->vm_numa_stat_diff[i] = 0;
 894				atomic_long_add(v, &zone->vm_numa_stat[i]);
 895				global_numa_diff[i] += v;
 896			}
 897#endif
 898	}
 899
 900	for_each_online_pgdat(pgdat) {
 901		struct per_cpu_nodestat *p;
 902
 903		p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
 904
 905		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 906			if (p->vm_node_stat_diff[i]) {
 907				int v;
 908
 909				v = p->vm_node_stat_diff[i];
 910				p->vm_node_stat_diff[i] = 0;
 911				atomic_long_add(v, &pgdat->vm_stat[i]);
 912				global_node_diff[i] += v;
 913			}
 914	}
 915
 916#ifdef CONFIG_NUMA
 917	fold_diff(global_zone_diff, global_numa_diff, global_node_diff);
 918#else
 919	fold_diff(global_zone_diff, global_node_diff);
 920#endif
 921}
 922
 923/*
 924 * this is only called if !populated_zone(zone), which implies no other users of
 925 * pset->vm_stat_diff[] exsist.
 926 */
 927void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 928{
 929	int i;
 930
 931	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 932		if (pset->vm_stat_diff[i]) {
 933			int v = pset->vm_stat_diff[i];
 934			pset->vm_stat_diff[i] = 0;
 935			atomic_long_add(v, &zone->vm_stat[i]);
 936			atomic_long_add(v, &vm_zone_stat[i]);
 937		}
 938
 939#ifdef CONFIG_NUMA
 940	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 941		if (pset->vm_numa_stat_diff[i]) {
 942			int v = pset->vm_numa_stat_diff[i];
 943
 944			pset->vm_numa_stat_diff[i] = 0;
 945			atomic_long_add(v, &zone->vm_numa_stat[i]);
 946			atomic_long_add(v, &vm_numa_stat[i]);
 947		}
 948#endif
 949}
 950#endif
 951
 952#ifdef CONFIG_NUMA
 953void __inc_numa_state(struct zone *zone,
 954				 enum numa_stat_item item)
 955{
 956	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 957	u16 __percpu *p = pcp->vm_numa_stat_diff + item;
 958	u16 v;
 959
 960	v = __this_cpu_inc_return(*p);
 961
 962	if (unlikely(v > NUMA_STATS_THRESHOLD)) {
 963		zone_numa_state_add(v, zone, item);
 964		__this_cpu_write(*p, 0);
 965	}
 966}
 967
 968/*
 969 * Determine the per node value of a stat item. This function
 970 * is called frequently in a NUMA machine, so try to be as
 971 * frugal as possible.
 
 
 
 
 
 972 */
 973unsigned long sum_zone_node_page_state(int node,
 974				 enum zone_stat_item item)
 975{
 976	struct zone *zones = NODE_DATA(node)->node_zones;
 977	int i;
 978	unsigned long count = 0;
 979
 980	for (i = 0; i < MAX_NR_ZONES; i++)
 981		count += zone_page_state(zones + i, item);
 982
 983	return count;
 
 
 
 984}
 985
 986/*
 987 * Determine the per node value of a numa stat item. To avoid deviation,
 988 * the per cpu stat number in vm_numa_stat_diff[] is also included.
 989 */
 990unsigned long sum_zone_numa_state(int node,
 991				 enum numa_stat_item item)
 992{
 993	struct zone *zones = NODE_DATA(node)->node_zones;
 994	int i;
 995	unsigned long count = 0;
 996
 997	for (i = 0; i < MAX_NR_ZONES; i++)
 998		count += zone_numa_state_snapshot(zones + i, item);
 999
1000	return count;
1001}
1002
1003/*
1004 * Determine the per node value of a stat item.
1005 */
1006unsigned long node_page_state_pages(struct pglist_data *pgdat,
1007				    enum node_stat_item item)
1008{
1009	long x = atomic_long_read(&pgdat->vm_stat[item]);
1010#ifdef CONFIG_SMP
1011	if (x < 0)
1012		x = 0;
1013#endif
1014	return x;
 
1015}
1016
1017unsigned long node_page_state(struct pglist_data *pgdat,
1018			      enum node_stat_item item)
1019{
1020	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
1021
1022	return node_page_state_pages(pgdat, item);
1023}
1024#endif
1025
1026#ifdef CONFIG_COMPACTION
1027
1028struct contig_page_info {
1029	unsigned long free_pages;
1030	unsigned long free_blocks_total;
1031	unsigned long free_blocks_suitable;
1032};
1033
1034/*
1035 * Calculate the number of free pages in a zone, how many contiguous
1036 * pages are free and how many are large enough to satisfy an allocation of
1037 * the target size. Note that this function makes no attempt to estimate
1038 * how many suitable free blocks there *might* be if MOVABLE pages were
1039 * migrated. Calculating that is possible, but expensive and can be
1040 * figured out from userspace
1041 */
1042static void fill_contig_page_info(struct zone *zone,
1043				unsigned int suitable_order,
1044				struct contig_page_info *info)
1045{
1046	unsigned int order;
1047
1048	info->free_pages = 0;
1049	info->free_blocks_total = 0;
1050	info->free_blocks_suitable = 0;
1051
1052	for (order = 0; order < MAX_ORDER; order++) {
1053		unsigned long blocks;
1054
1055		/* Count number of free blocks */
1056		blocks = zone->free_area[order].nr_free;
1057		info->free_blocks_total += blocks;
1058
1059		/* Count free base pages */
1060		info->free_pages += blocks << order;
1061
1062		/* Count the suitable free blocks */
1063		if (order >= suitable_order)
1064			info->free_blocks_suitable += blocks <<
1065						(order - suitable_order);
1066	}
1067}
1068
1069/*
1070 * A fragmentation index only makes sense if an allocation of a requested
1071 * size would fail. If that is true, the fragmentation index indicates
1072 * whether external fragmentation or a lack of memory was the problem.
1073 * The value can be used to determine if page reclaim or compaction
1074 * should be used
1075 */
1076static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
1077{
1078	unsigned long requested = 1UL << order;
1079
1080	if (WARN_ON_ONCE(order >= MAX_ORDER))
1081		return 0;
1082
1083	if (!info->free_blocks_total)
1084		return 0;
1085
1086	/* Fragmentation index only makes sense when a request would fail */
1087	if (info->free_blocks_suitable)
1088		return -1000;
1089
1090	/*
1091	 * Index is between 0 and 1 so return within 3 decimal places
1092	 *
1093	 * 0 => allocation would fail due to lack of memory
1094	 * 1 => allocation would fail due to fragmentation
1095	 */
1096	return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
1097}
1098
1099/*
1100 * Calculates external fragmentation within a zone wrt the given order.
1101 * It is defined as the percentage of pages found in blocks of size
1102 * less than 1 << order. It returns values in range [0, 100].
1103 */
1104unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
1105{
1106	struct contig_page_info info;
1107
1108	fill_contig_page_info(zone, order, &info);
1109	if (info.free_pages == 0)
1110		return 0;
1111
1112	return div_u64((info.free_pages -
1113			(info.free_blocks_suitable << order)) * 100,
1114			info.free_pages);
1115}
1116
1117/* Same as __fragmentation index but allocs contig_page_info on stack */
1118int fragmentation_index(struct zone *zone, unsigned int order)
1119{
1120	struct contig_page_info info;
1121
1122	fill_contig_page_info(zone, order, &info);
1123	return __fragmentation_index(order, &info);
1124}
1125#endif
1126
1127#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
1128    defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
1129#ifdef CONFIG_ZONE_DMA
1130#define TEXT_FOR_DMA(xx) xx "_dma",
1131#else
1132#define TEXT_FOR_DMA(xx)
1133#endif
1134
1135#ifdef CONFIG_ZONE_DMA32
1136#define TEXT_FOR_DMA32(xx) xx "_dma32",
1137#else
1138#define TEXT_FOR_DMA32(xx)
1139#endif
1140
1141#ifdef CONFIG_HIGHMEM
1142#define TEXT_FOR_HIGHMEM(xx) xx "_high",
1143#else
1144#define TEXT_FOR_HIGHMEM(xx)
1145#endif
1146
1147#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
1148					TEXT_FOR_HIGHMEM(xx) xx "_movable",
1149
1150const char * const vmstat_text[] = {
1151	/* enum zone_stat_item counters */
1152	"nr_free_pages",
1153	"nr_zone_inactive_anon",
1154	"nr_zone_active_anon",
1155	"nr_zone_inactive_file",
1156	"nr_zone_active_file",
1157	"nr_zone_unevictable",
1158	"nr_zone_write_pending",
1159	"nr_mlock",
1160	"nr_page_table_pages",
1161	"nr_bounce",
1162#if IS_ENABLED(CONFIG_ZSMALLOC)
1163	"nr_zspages",
1164#endif
1165	"nr_free_cma",
1166
1167	/* enum numa_stat_item counters */
1168#ifdef CONFIG_NUMA
1169	"numa_hit",
1170	"numa_miss",
1171	"numa_foreign",
1172	"numa_interleave",
1173	"numa_local",
1174	"numa_other",
1175#endif
1176
1177	/* enum node_stat_item counters */
1178	"nr_inactive_anon",
1179	"nr_active_anon",
1180	"nr_inactive_file",
1181	"nr_active_file",
1182	"nr_unevictable",
1183	"nr_slab_reclaimable",
1184	"nr_slab_unreclaimable",
1185	"nr_isolated_anon",
1186	"nr_isolated_file",
1187	"workingset_nodes",
1188	"workingset_refault_anon",
1189	"workingset_refault_file",
1190	"workingset_activate_anon",
1191	"workingset_activate_file",
1192	"workingset_restore_anon",
1193	"workingset_restore_file",
1194	"workingset_nodereclaim",
1195	"nr_anon_pages",
1196	"nr_mapped",
1197	"nr_file_pages",
1198	"nr_dirty",
1199	"nr_writeback",
1200	"nr_writeback_temp",
1201	"nr_shmem",
1202	"nr_shmem_hugepages",
1203	"nr_shmem_pmdmapped",
1204	"nr_file_hugepages",
1205	"nr_file_pmdmapped",
1206	"nr_anon_transparent_hugepages",
1207	"nr_vmscan_write",
1208	"nr_vmscan_immediate_reclaim",
 
 
 
 
1209	"nr_dirtied",
1210	"nr_written",
1211	"nr_kernel_misc_reclaimable",
1212	"nr_foll_pin_acquired",
1213	"nr_foll_pin_released",
1214	"nr_kernel_stack",
1215#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
1216	"nr_shadow_call_stack",
 
 
 
1217#endif
 
 
 
 
 
1218
1219	/* enum writeback_stat_item counters */
1220	"nr_dirty_threshold",
1221	"nr_dirty_background_threshold",
1222
1223#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
1224	/* enum vm_event_item counters */
1225	"pgpgin",
1226	"pgpgout",
1227	"pswpin",
1228	"pswpout",
1229
1230	TEXTS_FOR_ZONES("pgalloc")
1231	TEXTS_FOR_ZONES("allocstall")
1232	TEXTS_FOR_ZONES("pgskip")
1233
1234	"pgfree",
1235	"pgactivate",
1236	"pgdeactivate",
1237	"pglazyfree",
1238
1239	"pgfault",
1240	"pgmajfault",
1241	"pglazyfreed",
1242
1243	"pgrefill",
1244	"pgreuse",
1245	"pgsteal_kswapd",
1246	"pgsteal_direct",
1247	"pgscan_kswapd",
1248	"pgscan_direct",
1249	"pgscan_direct_throttle",
1250	"pgscan_anon",
1251	"pgscan_file",
1252	"pgsteal_anon",
1253	"pgsteal_file",
1254
1255#ifdef CONFIG_NUMA
1256	"zone_reclaim_failed",
1257#endif
1258	"pginodesteal",
1259	"slabs_scanned",
1260	"kswapd_inodesteal",
1261	"kswapd_low_wmark_hit_quickly",
1262	"kswapd_high_wmark_hit_quickly",
1263	"pageoutrun",
 
1264
1265	"pgrotated",
1266
1267	"drop_pagecache",
1268	"drop_slab",
1269	"oom_kill",
1270
1271#ifdef CONFIG_NUMA_BALANCING
1272	"numa_pte_updates",
1273	"numa_huge_pte_updates",
1274	"numa_hint_faults",
1275	"numa_hint_faults_local",
1276	"numa_pages_migrated",
1277#endif
1278#ifdef CONFIG_MIGRATION
1279	"pgmigrate_success",
1280	"pgmigrate_fail",
1281	"thp_migration_success",
1282	"thp_migration_fail",
1283	"thp_migration_split",
1284#endif
1285#ifdef CONFIG_COMPACTION
1286	"compact_migrate_scanned",
1287	"compact_free_scanned",
1288	"compact_isolated",
1289	"compact_stall",
1290	"compact_fail",
1291	"compact_success",
1292	"compact_daemon_wake",
1293	"compact_daemon_migrate_scanned",
1294	"compact_daemon_free_scanned",
1295#endif
1296
1297#ifdef CONFIG_HUGETLB_PAGE
1298	"htlb_buddy_alloc_success",
1299	"htlb_buddy_alloc_fail",
1300#endif
1301	"unevictable_pgs_culled",
1302	"unevictable_pgs_scanned",
1303	"unevictable_pgs_rescued",
1304	"unevictable_pgs_mlocked",
1305	"unevictable_pgs_munlocked",
1306	"unevictable_pgs_cleared",
1307	"unevictable_pgs_stranded",
1308
1309#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1310	"thp_fault_alloc",
1311	"thp_fault_fallback",
1312	"thp_fault_fallback_charge",
1313	"thp_collapse_alloc",
1314	"thp_collapse_alloc_failed",
1315	"thp_file_alloc",
1316	"thp_file_fallback",
1317	"thp_file_fallback_charge",
1318	"thp_file_mapped",
1319	"thp_split_page",
1320	"thp_split_page_failed",
1321	"thp_deferred_split_page",
1322	"thp_split_pmd",
1323#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1324	"thp_split_pud",
1325#endif
1326	"thp_zero_page_alloc",
1327	"thp_zero_page_alloc_failed",
1328	"thp_swpout",
1329	"thp_swpout_fallback",
1330#endif
1331#ifdef CONFIG_MEMORY_BALLOON
1332	"balloon_inflate",
1333	"balloon_deflate",
1334#ifdef CONFIG_BALLOON_COMPACTION
1335	"balloon_migrate",
1336#endif
1337#endif /* CONFIG_MEMORY_BALLOON */
1338#ifdef CONFIG_DEBUG_TLBFLUSH
 
1339	"nr_tlb_remote_flush",
1340	"nr_tlb_remote_flush_received",
 
1341	"nr_tlb_local_flush_all",
1342	"nr_tlb_local_flush_one",
1343#endif /* CONFIG_DEBUG_TLBFLUSH */
1344
1345#ifdef CONFIG_DEBUG_VM_VMACACHE
1346	"vmacache_find_calls",
1347	"vmacache_find_hits",
 
1348#endif
1349#ifdef CONFIG_SWAP
1350	"swap_ra",
1351	"swap_ra_hit",
1352#endif
1353#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
1354};
1355#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
 
1356
1357#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1358     defined(CONFIG_PROC_FS)
1359static void *frag_start(struct seq_file *m, loff_t *pos)
1360{
1361	pg_data_t *pgdat;
1362	loff_t node = *pos;
1363
1364	for (pgdat = first_online_pgdat();
1365	     pgdat && node;
1366	     pgdat = next_online_pgdat(pgdat))
1367		--node;
1368
1369	return pgdat;
1370}
1371
1372static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1373{
1374	pg_data_t *pgdat = (pg_data_t *)arg;
1375
1376	(*pos)++;
1377	return next_online_pgdat(pgdat);
1378}
1379
1380static void frag_stop(struct seq_file *m, void *arg)
1381{
1382}
1383
1384/*
1385 * Walk zones in a node and print using a callback.
1386 * If @assert_populated is true, only use callback for zones that are populated.
1387 */
1388static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1389		bool assert_populated, bool nolock,
1390		void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1391{
1392	struct zone *zone;
1393	struct zone *node_zones = pgdat->node_zones;
1394	unsigned long flags;
1395
1396	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1397		if (assert_populated && !populated_zone(zone))
1398			continue;
1399
1400		if (!nolock)
1401			spin_lock_irqsave(&zone->lock, flags);
1402		print(m, pgdat, zone);
1403		if (!nolock)
1404			spin_unlock_irqrestore(&zone->lock, flags);
1405	}
1406}
1407#endif
1408
1409#ifdef CONFIG_PROC_FS
1410static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1411						struct zone *zone)
1412{
1413	int order;
1414
1415	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1416	for (order = 0; order < MAX_ORDER; ++order)
1417		seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
1418	seq_putc(m, '\n');
1419}
1420
1421/*
1422 * This walks the free areas for each zone.
1423 */
1424static int frag_show(struct seq_file *m, void *arg)
1425{
1426	pg_data_t *pgdat = (pg_data_t *)arg;
1427	walk_zones_in_node(m, pgdat, true, false, frag_show_print);
1428	return 0;
1429}
1430
1431static void pagetypeinfo_showfree_print(struct seq_file *m,
1432					pg_data_t *pgdat, struct zone *zone)
1433{
1434	int order, mtype;
1435
1436	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1437		seq_printf(m, "Node %4d, zone %8s, type %12s ",
1438					pgdat->node_id,
1439					zone->name,
1440					migratetype_names[mtype]);
1441		for (order = 0; order < MAX_ORDER; ++order) {
1442			unsigned long freecount = 0;
1443			struct free_area *area;
1444			struct list_head *curr;
1445			bool overflow = false;
1446
1447			area = &(zone->free_area[order]);
1448
1449			list_for_each(curr, &area->free_list[mtype]) {
1450				/*
1451				 * Cap the free_list iteration because it might
1452				 * be really large and we are under a spinlock
1453				 * so a long time spent here could trigger a
1454				 * hard lockup detector. Anyway this is a
1455				 * debugging tool so knowing there is a handful
1456				 * of pages of this order should be more than
1457				 * sufficient.
1458				 */
1459				if (++freecount >= 100000) {
1460					overflow = true;
1461					break;
1462				}
1463			}
1464			seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
1465			spin_unlock_irq(&zone->lock);
1466			cond_resched();
1467			spin_lock_irq(&zone->lock);
1468		}
1469		seq_putc(m, '\n');
1470	}
1471}
1472
1473/* Print out the free pages at each order for each migatetype */
1474static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
1475{
1476	int order;
1477	pg_data_t *pgdat = (pg_data_t *)arg;
1478
1479	/* Print header */
1480	seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1481	for (order = 0; order < MAX_ORDER; ++order)
1482		seq_printf(m, "%6d ", order);
1483	seq_putc(m, '\n');
1484
1485	walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
1486
1487	return 0;
1488}
1489
1490static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1491					pg_data_t *pgdat, struct zone *zone)
1492{
1493	int mtype;
1494	unsigned long pfn;
1495	unsigned long start_pfn = zone->zone_start_pfn;
1496	unsigned long end_pfn = zone_end_pfn(zone);
1497	unsigned long count[MIGRATE_TYPES] = { 0, };
1498
1499	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1500		struct page *page;
1501
1502		page = pfn_to_online_page(pfn);
1503		if (!page)
1504			continue;
1505
 
 
1506		/* Watch for unexpected holes punched in the memmap */
1507		if (!memmap_valid_within(pfn, page, zone))
1508			continue;
1509
1510		if (page_zone(page) != zone)
1511			continue;
1512
1513		mtype = get_pageblock_migratetype(page);
1514
1515		if (mtype < MIGRATE_TYPES)
1516			count[mtype]++;
1517	}
1518
1519	/* Print counts */
1520	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1521	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1522		seq_printf(m, "%12lu ", count[mtype]);
1523	seq_putc(m, '\n');
1524}
1525
1526/* Print out the number of pageblocks for each migratetype */
1527static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1528{
1529	int mtype;
1530	pg_data_t *pgdat = (pg_data_t *)arg;
1531
1532	seq_printf(m, "\n%-23s", "Number of blocks type ");
1533	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1534		seq_printf(m, "%12s ", migratetype_names[mtype]);
1535	seq_putc(m, '\n');
1536	walk_zones_in_node(m, pgdat, true, false,
1537		pagetypeinfo_showblockcount_print);
1538
1539	return 0;
1540}
1541
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1542/*
1543 * Print out the number of pageblocks for each migratetype that contain pages
1544 * of other types. This gives an indication of how well fallbacks are being
1545 * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1546 * to determine what is going on
1547 */
1548static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1549{
1550#ifdef CONFIG_PAGE_OWNER
1551	int mtype;
1552
1553	if (!static_branch_unlikely(&page_owner_inited))
1554		return;
1555
1556	drain_all_pages(NULL);
1557
1558	seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1559	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1560		seq_printf(m, "%12s ", migratetype_names[mtype]);
1561	seq_putc(m, '\n');
1562
1563	walk_zones_in_node(m, pgdat, true, true,
1564		pagetypeinfo_showmixedcount_print);
1565#endif /* CONFIG_PAGE_OWNER */
1566}
1567
1568/*
1569 * This prints out statistics in relation to grouping pages by mobility.
1570 * It is expensive to collect so do not constantly read the file.
1571 */
1572static int pagetypeinfo_show(struct seq_file *m, void *arg)
1573{
1574	pg_data_t *pgdat = (pg_data_t *)arg;
1575
1576	/* check memoryless node */
1577	if (!node_state(pgdat->node_id, N_MEMORY))
1578		return 0;
1579
1580	seq_printf(m, "Page block order: %d\n", pageblock_order);
1581	seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
1582	seq_putc(m, '\n');
1583	pagetypeinfo_showfree(m, pgdat);
1584	pagetypeinfo_showblockcount(m, pgdat);
1585	pagetypeinfo_showmixedcount(m, pgdat);
1586
1587	return 0;
1588}
1589
1590static const struct seq_operations fragmentation_op = {
1591	.start	= frag_start,
1592	.next	= frag_next,
1593	.stop	= frag_stop,
1594	.show	= frag_show,
1595};
1596
 
 
 
 
 
 
 
 
 
 
 
 
1597static const struct seq_operations pagetypeinfo_op = {
1598	.start	= frag_start,
1599	.next	= frag_next,
1600	.stop	= frag_stop,
1601	.show	= pagetypeinfo_show,
1602};
1603
1604static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1605{
1606	int zid;
1607
1608	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1609		struct zone *compare = &pgdat->node_zones[zid];
1610
1611		if (populated_zone(compare))
1612			return zone == compare;
1613	}
1614
1615	return false;
1616}
1617
 
 
 
 
 
 
 
1618static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1619							struct zone *zone)
1620{
1621	int i;
1622	seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1623	if (is_zone_first_populated(pgdat, zone)) {
1624		seq_printf(m, "\n  per-node stats");
1625		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1626			seq_printf(m, "\n      %-12s %lu", node_stat_name(i),
1627				   node_page_state_pages(pgdat, i));
1628		}
1629	}
1630	seq_printf(m,
1631		   "\n  pages free     %lu"
1632		   "\n        min      %lu"
1633		   "\n        low      %lu"
1634		   "\n        high     %lu"
 
1635		   "\n        spanned  %lu"
1636		   "\n        present  %lu"
1637		   "\n        managed  %lu",
1638		   zone_page_state(zone, NR_FREE_PAGES),
1639		   min_wmark_pages(zone),
1640		   low_wmark_pages(zone),
1641		   high_wmark_pages(zone),
 
1642		   zone->spanned_pages,
1643		   zone->present_pages,
1644		   zone_managed_pages(zone));
 
 
 
 
1645
1646	seq_printf(m,
1647		   "\n        protection: (%ld",
1648		   zone->lowmem_reserve[0]);
1649	for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1650		seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1651	seq_putc(m, ')');
1652
1653	/* If unpopulated, no other information is useful */
1654	if (!populated_zone(zone)) {
1655		seq_putc(m, '\n');
1656		return;
1657	}
1658
1659	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1660		seq_printf(m, "\n      %-12s %lu", zone_stat_name(i),
1661			   zone_page_state(zone, i));
1662
1663#ifdef CONFIG_NUMA
1664	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1665		seq_printf(m, "\n      %-12s %lu", numa_stat_name(i),
1666			   zone_numa_state_snapshot(zone, i));
1667#endif
1668
1669	seq_printf(m, "\n  pagesets");
1670	for_each_online_cpu(i) {
1671		struct per_cpu_pageset *pageset;
1672
1673		pageset = per_cpu_ptr(zone->pageset, i);
1674		seq_printf(m,
1675			   "\n    cpu: %i"
1676			   "\n              count: %i"
1677			   "\n              high:  %i"
1678			   "\n              batch: %i",
1679			   i,
1680			   pageset->pcp.count,
1681			   pageset->pcp.high,
1682			   pageset->pcp.batch);
1683#ifdef CONFIG_SMP
1684		seq_printf(m, "\n  vm stats threshold: %d",
1685				pageset->stat_threshold);
1686#endif
1687	}
1688	seq_printf(m,
1689		   "\n  node_unreclaimable:  %u"
1690		   "\n  start_pfn:           %lu",
1691		   pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
1692		   zone->zone_start_pfn);
 
 
1693	seq_putc(m, '\n');
1694}
1695
1696/*
1697 * Output information about zones in @pgdat.  All zones are printed regardless
1698 * of whether they are populated or not: lowmem_reserve_ratio operates on the
1699 * set of all zones and userspace would not be aware of such zones if they are
1700 * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
1701 */
1702static int zoneinfo_show(struct seq_file *m, void *arg)
1703{
1704	pg_data_t *pgdat = (pg_data_t *)arg;
1705	walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
1706	return 0;
1707}
1708
1709static const struct seq_operations zoneinfo_op = {
1710	.start	= frag_start, /* iterate over all zones. The same as in
1711			       * fragmentation. */
1712	.next	= frag_next,
1713	.stop	= frag_stop,
1714	.show	= zoneinfo_show,
1715};
1716
1717#define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
1718			 NR_VM_NUMA_STAT_ITEMS + \
1719			 NR_VM_NODE_STAT_ITEMS + \
1720			 NR_VM_WRITEBACK_STAT_ITEMS + \
1721			 (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
1722			  NR_VM_EVENT_ITEMS : 0))
 
 
 
 
 
 
 
 
 
 
 
1723
1724static void *vmstat_start(struct seq_file *m, loff_t *pos)
1725{
1726	unsigned long *v;
1727	int i;
1728
1729	if (*pos >= NR_VMSTAT_ITEMS)
1730		return NULL;
 
 
 
 
 
 
1731
1732	BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
1733	v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
1734	m->private = v;
1735	if (!v)
1736		return ERR_PTR(-ENOMEM);
1737	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1738		v[i] = global_zone_page_state(i);
1739	v += NR_VM_ZONE_STAT_ITEMS;
1740
1741#ifdef CONFIG_NUMA
1742	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1743		v[i] = global_numa_state(i);
1744	v += NR_VM_NUMA_STAT_ITEMS;
1745#endif
1746
1747	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
1748		v[i] = global_node_page_state_pages(i);
1749	v += NR_VM_NODE_STAT_ITEMS;
1750
1751	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1752			    v + NR_DIRTY_THRESHOLD);
1753	v += NR_VM_WRITEBACK_STAT_ITEMS;
1754
1755#ifdef CONFIG_VM_EVENT_COUNTERS
1756	all_vm_events(v);
1757	v[PGPGIN] /= 2;		/* sectors -> kbytes */
1758	v[PGPGOUT] /= 2;
1759#endif
1760	return (unsigned long *)m->private + *pos;
1761}
1762
1763static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1764{
1765	(*pos)++;
1766	if (*pos >= NR_VMSTAT_ITEMS)
1767		return NULL;
1768	return (unsigned long *)m->private + *pos;
1769}
1770
1771static int vmstat_show(struct seq_file *m, void *arg)
1772{
1773	unsigned long *l = arg;
1774	unsigned long off = l - (unsigned long *)m->private;
1775
1776	seq_puts(m, vmstat_text[off]);
1777	seq_put_decimal_ull(m, " ", *l);
1778	seq_putc(m, '\n');
1779
1780	if (off == NR_VMSTAT_ITEMS - 1) {
1781		/*
1782		 * We've come to the end - add any deprecated counters to avoid
1783		 * breaking userspace which might depend on them being present.
1784		 */
1785		seq_puts(m, "nr_unstable 0\n");
1786	}
1787	return 0;
1788}
1789
1790static void vmstat_stop(struct seq_file *m, void *arg)
1791{
1792	kfree(m->private);
1793	m->private = NULL;
1794}
1795
1796static const struct seq_operations vmstat_op = {
1797	.start	= vmstat_start,
1798	.next	= vmstat_next,
1799	.stop	= vmstat_stop,
1800	.show	= vmstat_show,
1801};
1802#endif /* CONFIG_PROC_FS */
1803
1804#ifdef CONFIG_SMP
1805static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1806int sysctl_stat_interval __read_mostly = HZ;
1807
1808#ifdef CONFIG_PROC_FS
1809static void refresh_vm_stats(struct work_struct *work)
1810{
1811	refresh_cpu_vm_stats(true);
1812}
1813
1814int vmstat_refresh(struct ctl_table *table, int write,
1815		   void *buffer, size_t *lenp, loff_t *ppos)
1816{
1817	long val;
1818	int err;
1819	int i;
1820
1821	/*
1822	 * The regular update, every sysctl_stat_interval, may come later
1823	 * than expected: leaving a significant amount in per_cpu buckets.
1824	 * This is particularly misleading when checking a quantity of HUGE
1825	 * pages, immediately after running a test.  /proc/sys/vm/stat_refresh,
1826	 * which can equally be echo'ed to or cat'ted from (by root),
1827	 * can be used to update the stats just before reading them.
1828	 *
1829	 * Oh, and since global_zone_page_state() etc. are so careful to hide
1830	 * transiently negative values, report an error here if any of
1831	 * the stats is negative, so we know to go looking for imbalance.
1832	 */
1833	err = schedule_on_each_cpu(refresh_vm_stats);
1834	if (err)
1835		return err;
1836	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1837		val = atomic_long_read(&vm_zone_stat[i]);
1838		if (val < 0) {
1839			pr_warn("%s: %s %ld\n",
1840				__func__, zone_stat_name(i), val);
1841			err = -EINVAL;
1842		}
1843	}
1844#ifdef CONFIG_NUMA
1845	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
1846		val = atomic_long_read(&vm_numa_stat[i]);
1847		if (val < 0) {
1848			pr_warn("%s: %s %ld\n",
1849				__func__, numa_stat_name(i), val);
1850			err = -EINVAL;
1851		}
1852	}
1853#endif
1854	if (err)
1855		return err;
1856	if (write)
1857		*ppos += *lenp;
1858	else
1859		*lenp = 0;
1860	return 0;
1861}
1862#endif /* CONFIG_PROC_FS */
1863
 
 
 
 
 
 
1864static void vmstat_update(struct work_struct *w)
1865{
1866	if (refresh_cpu_vm_stats(true)) {
1867		/*
1868		 * Counters were updated so we expect more updates
1869		 * to occur in the future. Keep on running the
1870		 * update worker thread.
 
 
1871		 */
1872		queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
 
 
1873				this_cpu_ptr(&vmstat_work),
1874				round_jiffies_relative(sysctl_stat_interval));
 
 
 
 
 
 
 
 
 
 
1875	}
1876}
1877
1878/*
1879 * Switch off vmstat processing and then fold all the remaining differentials
1880 * until the diffs stay at zero. The function is used by NOHZ and can only be
1881 * invoked when tick processing is not active.
1882 */
1883/*
1884 * Check if the diffs for a certain cpu indicate that
1885 * an update is needed.
1886 */
1887static bool need_update(int cpu)
1888{
1889	struct zone *zone;
1890
1891	for_each_populated_zone(zone) {
1892		struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu);
1893
1894		BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
1895#ifdef CONFIG_NUMA
1896		BUILD_BUG_ON(sizeof(p->vm_numa_stat_diff[0]) != 2);
1897#endif
1898
1899		/*
1900		 * The fast way of checking if there are any vmstat diffs.
 
1901		 */
1902		if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS *
1903			       sizeof(p->vm_stat_diff[0])))
1904			return true;
1905#ifdef CONFIG_NUMA
1906		if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS *
1907			       sizeof(p->vm_numa_stat_diff[0])))
1908			return true;
1909#endif
1910	}
1911	return false;
1912}
1913
1914/*
1915 * Switch off vmstat processing and then fold all the remaining differentials
1916 * until the diffs stay at zero. The function is used by NOHZ and can only be
1917 * invoked when tick processing is not active.
1918 */
1919void quiet_vmstat(void)
1920{
1921	if (system_state != SYSTEM_RUNNING)
1922		return;
1923
1924	if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
 
 
 
 
1925		return;
1926
1927	if (!need_update(smp_processor_id()))
1928		return;
1929
1930	/*
1931	 * Just refresh counters and do not care about the pending delayed
1932	 * vmstat_update. It doesn't fire that often to matter and canceling
1933	 * it would be too expensive from this path.
1934	 * vmstat_shepherd will take care about that for us.
1935	 */
1936	refresh_cpu_vm_stats(false);
1937}
1938
 
1939/*
1940 * Shepherd worker thread that checks the
1941 * differentials of processors that have their worker
1942 * threads for vm statistics updates disabled because of
1943 * inactivity.
1944 */
1945static void vmstat_shepherd(struct work_struct *w);
1946
1947static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
1948
1949static void vmstat_shepherd(struct work_struct *w)
1950{
1951	int cpu;
1952
1953	get_online_cpus();
1954	/* Check processors whose vmstat worker threads have been disabled */
1955	for_each_online_cpu(cpu) {
1956		struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
1957
1958		if (!delayed_work_pending(dw) && need_update(cpu))
1959			queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
 
 
 
 
 
 
 
 
 
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
v4.6
 
   1/*
   2 *  linux/mm/vmstat.c
   3 *
   4 *  Manages VM statistics
   5 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   6 *
   7 *  zoned VM statistics
   8 *  Copyright (C) 2006 Silicon Graphics, Inc.,
   9 *		Christoph Lameter <christoph@lameter.com>
  10 *  Copyright (C) 2008-2014 Christoph Lameter
  11 */
  12#include <linux/fs.h>
  13#include <linux/mm.h>
  14#include <linux/err.h>
  15#include <linux/module.h>
  16#include <linux/slab.h>
  17#include <linux/cpu.h>
  18#include <linux/cpumask.h>
  19#include <linux/vmstat.h>
  20#include <linux/proc_fs.h>
  21#include <linux/seq_file.h>
  22#include <linux/debugfs.h>
  23#include <linux/sched.h>
  24#include <linux/math64.h>
  25#include <linux/writeback.h>
  26#include <linux/compaction.h>
  27#include <linux/mm_inline.h>
  28#include <linux/page_ext.h>
  29#include <linux/page_owner.h>
  30
  31#include "internal.h"
  32
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  33#ifdef CONFIG_VM_EVENT_COUNTERS
  34DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
  35EXPORT_PER_CPU_SYMBOL(vm_event_states);
  36
  37static void sum_vm_events(unsigned long *ret)
  38{
  39	int cpu;
  40	int i;
  41
  42	memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
  43
  44	for_each_online_cpu(cpu) {
  45		struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
  46
  47		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
  48			ret[i] += this->event[i];
  49	}
  50}
  51
  52/*
  53 * Accumulate the vm event counters across all CPUs.
  54 * The result is unavoidably approximate - it can change
  55 * during and after execution of this function.
  56*/
  57void all_vm_events(unsigned long *ret)
  58{
  59	get_online_cpus();
  60	sum_vm_events(ret);
  61	put_online_cpus();
  62}
  63EXPORT_SYMBOL_GPL(all_vm_events);
  64
  65/*
  66 * Fold the foreign cpu events into our own.
  67 *
  68 * This is adding to the events on one processor
  69 * but keeps the global counts constant.
  70 */
  71void vm_events_fold_cpu(int cpu)
  72{
  73	struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
  74	int i;
  75
  76	for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
  77		count_vm_events(i, fold_state->event[i]);
  78		fold_state->event[i] = 0;
  79	}
  80}
  81
  82#endif /* CONFIG_VM_EVENT_COUNTERS */
  83
  84/*
  85 * Manage combined zone based / global counters
  86 *
  87 * vm_stat contains the global counters
  88 */
  89atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
  90EXPORT_SYMBOL(vm_stat);
 
 
 
 
  91
  92#ifdef CONFIG_SMP
  93
  94int calculate_pressure_threshold(struct zone *zone)
  95{
  96	int threshold;
  97	int watermark_distance;
  98
  99	/*
 100	 * As vmstats are not up to date, there is drift between the estimated
 101	 * and real values. For high thresholds and a high number of CPUs, it
 102	 * is possible for the min watermark to be breached while the estimated
 103	 * value looks fine. The pressure threshold is a reduced value such
 104	 * that even the maximum amount of drift will not accidentally breach
 105	 * the min watermark
 106	 */
 107	watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
 108	threshold = max(1, (int)(watermark_distance / num_online_cpus()));
 109
 110	/*
 111	 * Maximum threshold is 125
 112	 */
 113	threshold = min(125, threshold);
 114
 115	return threshold;
 116}
 117
 118int calculate_normal_threshold(struct zone *zone)
 119{
 120	int threshold;
 121	int mem;	/* memory in 128 MB units */
 122
 123	/*
 124	 * The threshold scales with the number of processors and the amount
 125	 * of memory per zone. More memory means that we can defer updates for
 126	 * longer, more processors could lead to more contention.
 127 	 * fls() is used to have a cheap way of logarithmic scaling.
 128	 *
 129	 * Some sample thresholds:
 130	 *
 131	 * Threshold	Processors	(fls)	Zonesize	fls(mem+1)
 132	 * ------------------------------------------------------------------
 133	 * 8		1		1	0.9-1 GB	4
 134	 * 16		2		2	0.9-1 GB	4
 135	 * 20 		2		2	1-2 GB		5
 136	 * 24		2		2	2-4 GB		6
 137	 * 28		2		2	4-8 GB		7
 138	 * 32		2		2	8-16 GB		8
 139	 * 4		2		2	<128M		1
 140	 * 30		4		3	2-4 GB		5
 141	 * 48		4		3	8-16 GB		8
 142	 * 32		8		4	1-2 GB		4
 143	 * 32		8		4	0.9-1GB		4
 144	 * 10		16		5	<128M		1
 145	 * 40		16		5	900M		4
 146	 * 70		64		7	2-4 GB		5
 147	 * 84		64		7	4-8 GB		6
 148	 * 108		512		9	4-8 GB		6
 149	 * 125		1024		10	8-16 GB		8
 150	 * 125		1024		10	16-32 GB	9
 151	 */
 152
 153	mem = zone->managed_pages >> (27 - PAGE_SHIFT);
 154
 155	threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 156
 157	/*
 158	 * Maximum threshold is 125
 159	 */
 160	threshold = min(125, threshold);
 161
 162	return threshold;
 163}
 164
 165/*
 166 * Refresh the thresholds for each zone.
 167 */
 168void refresh_zone_stat_thresholds(void)
 169{
 
 170	struct zone *zone;
 171	int cpu;
 172	int threshold;
 173
 
 
 
 
 
 
 
 174	for_each_populated_zone(zone) {
 
 175		unsigned long max_drift, tolerate_drift;
 176
 177		threshold = calculate_normal_threshold(zone);
 178
 179		for_each_online_cpu(cpu)
 
 
 180			per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 181							= threshold;
 182
 
 
 
 
 
 
 183		/*
 184		 * Only set percpu_drift_mark if there is a danger that
 185		 * NR_FREE_PAGES reports the low watermark is ok when in fact
 186		 * the min watermark could be breached by an allocation
 187		 */
 188		tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 189		max_drift = num_online_cpus() * threshold;
 190		if (max_drift > tolerate_drift)
 191			zone->percpu_drift_mark = high_wmark_pages(zone) +
 192					max_drift;
 193	}
 194}
 195
 196void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 197				int (*calculate_pressure)(struct zone *))
 198{
 199	struct zone *zone;
 200	int cpu;
 201	int threshold;
 202	int i;
 203
 204	for (i = 0; i < pgdat->nr_zones; i++) {
 205		zone = &pgdat->node_zones[i];
 206		if (!zone->percpu_drift_mark)
 207			continue;
 208
 209		threshold = (*calculate_pressure)(zone);
 210		for_each_online_cpu(cpu)
 211			per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 212							= threshold;
 213	}
 214}
 215
 216/*
 217 * For use when we know that interrupts are disabled,
 218 * or when we know that preemption is disabled and that
 219 * particular counter cannot be updated from interrupt context.
 220 */
 221void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 222			   long delta)
 223{
 224	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 225	s8 __percpu *p = pcp->vm_stat_diff + item;
 226	long x;
 227	long t;
 228
 229	x = delta + __this_cpu_read(*p);
 230
 231	t = __this_cpu_read(pcp->stat_threshold);
 232
 233	if (unlikely(x > t || x < -t)) {
 234		zone_page_state_add(x, zone, item);
 235		x = 0;
 236	}
 237	__this_cpu_write(*p, x);
 238}
 239EXPORT_SYMBOL(__mod_zone_page_state);
 240
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 241/*
 242 * Optimized increment and decrement functions.
 243 *
 244 * These are only for a single page and therefore can take a struct page *
 245 * argument instead of struct zone *. This allows the inclusion of the code
 246 * generated for page_zone(page) into the optimized functions.
 247 *
 248 * No overflow check is necessary and therefore the differential can be
 249 * incremented or decremented in place which may allow the compilers to
 250 * generate better code.
 251 * The increment or decrement is known and therefore one boundary check can
 252 * be omitted.
 253 *
 254 * NOTE: These functions are very performance sensitive. Change only
 255 * with care.
 256 *
 257 * Some processors have inc/dec instructions that are atomic vs an interrupt.
 258 * However, the code must first determine the differential location in a zone
 259 * based on the processor number and then inc/dec the counter. There is no
 260 * guarantee without disabling preemption that the processor will not change
 261 * in between and therefore the atomicity vs. interrupt cannot be exploited
 262 * in a useful way here.
 263 */
 264void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 265{
 266	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 267	s8 __percpu *p = pcp->vm_stat_diff + item;
 268	s8 v, t;
 269
 270	v = __this_cpu_inc_return(*p);
 271	t = __this_cpu_read(pcp->stat_threshold);
 272	if (unlikely(v > t)) {
 273		s8 overstep = t >> 1;
 274
 275		zone_page_state_add(v + overstep, zone, item);
 276		__this_cpu_write(*p, -overstep);
 277	}
 278}
 279
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 280void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 281{
 282	__inc_zone_state(page_zone(page), item);
 283}
 284EXPORT_SYMBOL(__inc_zone_page_state);
 285
 
 
 
 
 
 
 286void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 287{
 288	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 289	s8 __percpu *p = pcp->vm_stat_diff + item;
 290	s8 v, t;
 291
 292	v = __this_cpu_dec_return(*p);
 293	t = __this_cpu_read(pcp->stat_threshold);
 294	if (unlikely(v < - t)) {
 295		s8 overstep = t >> 1;
 296
 297		zone_page_state_add(v - overstep, zone, item);
 298		__this_cpu_write(*p, overstep);
 299	}
 300}
 301
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 302void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 303{
 304	__dec_zone_state(page_zone(page), item);
 305}
 306EXPORT_SYMBOL(__dec_zone_page_state);
 307
 
 
 
 
 
 
 308#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 309/*
 310 * If we have cmpxchg_local support then we do not need to incur the overhead
 311 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 312 *
 313 * mod_state() modifies the zone counter state through atomic per cpu
 314 * operations.
 315 *
 316 * Overstep mode specifies how overstep should handled:
 317 *     0       No overstepping
 318 *     1       Overstepping half of threshold
 319 *     -1      Overstepping minus half of threshold
 320*/
 321static inline void mod_state(struct zone *zone, enum zone_stat_item item,
 322			     long delta, int overstep_mode)
 323{
 324	struct per_cpu_pageset __percpu *pcp = zone->pageset;
 325	s8 __percpu *p = pcp->vm_stat_diff + item;
 326	long o, n, t, z;
 327
 328	do {
 329		z = 0;  /* overflow to zone counters */
 330
 331		/*
 332		 * The fetching of the stat_threshold is racy. We may apply
 333		 * a counter threshold to the wrong the cpu if we get
 334		 * rescheduled while executing here. However, the next
 335		 * counter update will apply the threshold again and
 336		 * therefore bring the counter under the threshold again.
 337		 *
 338		 * Most of the time the thresholds are the same anyways
 339		 * for all cpus in a zone.
 340		 */
 341		t = this_cpu_read(pcp->stat_threshold);
 342
 343		o = this_cpu_read(*p);
 344		n = delta + o;
 345
 346		if (n > t || n < -t) {
 347			int os = overstep_mode * (t >> 1) ;
 348
 349			/* Overflow must be added to zone counters */
 350			z = n + os;
 351			n = -os;
 352		}
 353	} while (this_cpu_cmpxchg(*p, o, n) != o);
 354
 355	if (z)
 356		zone_page_state_add(z, zone, item);
 357}
 358
 359void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 360			 long delta)
 361{
 362	mod_state(zone, item, delta, 0);
 363}
 364EXPORT_SYMBOL(mod_zone_page_state);
 365
 366void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 367{
 368	mod_state(zone, item, 1, 1);
 369}
 370
 371void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 372{
 373	mod_state(page_zone(page), item, 1, 1);
 374}
 375EXPORT_SYMBOL(inc_zone_page_state);
 376
 377void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 378{
 379	mod_state(page_zone(page), item, -1, -1);
 380}
 381EXPORT_SYMBOL(dec_zone_page_state);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 382#else
 383/*
 384 * Use interrupt disable to serialize counter updates
 385 */
 386void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 387			 long delta)
 388{
 389	unsigned long flags;
 390
 391	local_irq_save(flags);
 392	__mod_zone_page_state(zone, item, delta);
 393	local_irq_restore(flags);
 394}
 395EXPORT_SYMBOL(mod_zone_page_state);
 396
 397void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 398{
 399	unsigned long flags;
 
 400
 
 401	local_irq_save(flags);
 402	__inc_zone_state(zone, item);
 403	local_irq_restore(flags);
 404}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 405
 406void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 407{
 408	unsigned long flags;
 409	struct zone *zone;
 410
 411	zone = page_zone(page);
 412	local_irq_save(flags);
 413	__inc_zone_state(zone, item);
 414	local_irq_restore(flags);
 415}
 416EXPORT_SYMBOL(inc_zone_page_state);
 417
 418void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 419{
 420	unsigned long flags;
 421
 422	local_irq_save(flags);
 423	__dec_zone_page_state(page, item);
 424	local_irq_restore(flags);
 425}
 426EXPORT_SYMBOL(dec_zone_page_state);
 427#endif
 428
 429
 430/*
 431 * Fold a differential into the global counters.
 432 * Returns the number of counters updated.
 433 */
 434static int fold_diff(int *diff)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 435{
 436	int i;
 437	int changes = 0;
 438
 439	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 440		if (diff[i]) {
 441			atomic_long_add(diff[i], &vm_stat[i]);
 
 
 
 
 
 
 442			changes++;
 443	}
 444	return changes;
 445}
 
 446
 447/*
 448 * Update the zone counters for the current cpu.
 449 *
 450 * Note that refresh_cpu_vm_stats strives to only access
 451 * node local memory. The per cpu pagesets on remote zones are placed
 452 * in the memory local to the processor using that pageset. So the
 453 * loop over all zones will access a series of cachelines local to
 454 * the processor.
 455 *
 456 * The call to zone_page_state_add updates the cachelines with the
 457 * statistics in the remote zone struct as well as the global cachelines
 458 * with the global counters. These could cause remote node cache line
 459 * bouncing and will have to be only done when necessary.
 460 *
 461 * The function returns the number of global counters updated.
 462 */
 463static int refresh_cpu_vm_stats(bool do_pagesets)
 464{
 
 465	struct zone *zone;
 466	int i;
 467	int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 
 
 
 
 468	int changes = 0;
 469
 470	for_each_populated_zone(zone) {
 471		struct per_cpu_pageset __percpu *p = zone->pageset;
 472
 473		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 474			int v;
 475
 476			v = this_cpu_xchg(p->vm_stat_diff[i], 0);
 477			if (v) {
 478
 479				atomic_long_add(v, &zone->vm_stat[i]);
 480				global_diff[i] += v;
 481#ifdef CONFIG_NUMA
 482				/* 3 seconds idle till flush */
 483				__this_cpu_write(p->expire, 3);
 484#endif
 485			}
 486		}
 487#ifdef CONFIG_NUMA
 
 
 
 
 
 
 
 
 
 
 
 
 488		if (do_pagesets) {
 489			cond_resched();
 490			/*
 491			 * Deal with draining the remote pageset of this
 492			 * processor
 493			 *
 494			 * Check if there are pages remaining in this pageset
 495			 * if not then there is nothing to expire.
 496			 */
 497			if (!__this_cpu_read(p->expire) ||
 498			       !__this_cpu_read(p->pcp.count))
 499				continue;
 500
 501			/*
 502			 * We never drain zones local to this processor.
 503			 */
 504			if (zone_to_nid(zone) == numa_node_id()) {
 505				__this_cpu_write(p->expire, 0);
 506				continue;
 507			}
 508
 509			if (__this_cpu_dec_return(p->expire))
 510				continue;
 511
 512			if (__this_cpu_read(p->pcp.count)) {
 513				drain_zone_pages(zone, this_cpu_ptr(&p->pcp));
 514				changes++;
 515			}
 516		}
 517#endif
 518	}
 519	changes += fold_diff(global_diff);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 520	return changes;
 521}
 522
 523/*
 524 * Fold the data for an offline cpu into the global array.
 525 * There cannot be any access by the offline cpu and therefore
 526 * synchronization is simplified.
 527 */
 528void cpu_vm_stats_fold(int cpu)
 529{
 
 530	struct zone *zone;
 531	int i;
 532	int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 
 
 
 
 533
 534	for_each_populated_zone(zone) {
 535		struct per_cpu_pageset *p;
 536
 537		p = per_cpu_ptr(zone->pageset, cpu);
 538
 539		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 540			if (p->vm_stat_diff[i]) {
 541				int v;
 542
 543				v = p->vm_stat_diff[i];
 544				p->vm_stat_diff[i] = 0;
 545				atomic_long_add(v, &zone->vm_stat[i]);
 546				global_diff[i] += v;
 
 
 
 
 
 
 
 
 
 
 
 547			}
 
 548	}
 549
 550	fold_diff(global_diff);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 551}
 552
 553/*
 554 * this is only called if !populated_zone(zone), which implies no other users of
 555 * pset->vm_stat_diff[] exsist.
 556 */
 557void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 558{
 559	int i;
 560
 561	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 562		if (pset->vm_stat_diff[i]) {
 563			int v = pset->vm_stat_diff[i];
 564			pset->vm_stat_diff[i] = 0;
 565			atomic_long_add(v, &zone->vm_stat[i]);
 566			atomic_long_add(v, &vm_stat[i]);
 
 
 
 
 
 
 
 
 
 
 567		}
 
 568}
 569#endif
 570
 571#ifdef CONFIG_NUMA
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 572/*
 573 * zonelist = the list of zones passed to the allocator
 574 * z 	    = the zone from which the allocation occurred.
 575 *
 576 * Must be called with interrupts disabled.
 577 *
 578 * When __GFP_OTHER_NODE is set assume the node of the preferred
 579 * zone is the local node. This is useful for daemons who allocate
 580 * memory on behalf of other processes.
 581 */
 582void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
 
 583{
 584	if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 585		__inc_zone_state(z, NUMA_HIT);
 586	} else {
 587		__inc_zone_state(z, NUMA_MISS);
 588		__inc_zone_state(preferred_zone, NUMA_FOREIGN);
 589	}
 590	if (z->node == ((flags & __GFP_OTHER_NODE) ?
 591			preferred_zone->node : numa_node_id()))
 592		__inc_zone_state(z, NUMA_LOCAL);
 593	else
 594		__inc_zone_state(z, NUMA_OTHER);
 595}
 596
 597/*
 598 * Determine the per node value of a stat item.
 
 599 */
 600unsigned long node_page_state(int node, enum zone_stat_item item)
 
 601{
 602	struct zone *zones = NODE_DATA(node)->node_zones;
 
 
 
 
 
 603
 604	return
 605#ifdef CONFIG_ZONE_DMA
 606		zone_page_state(&zones[ZONE_DMA], item) +
 607#endif
 608#ifdef CONFIG_ZONE_DMA32
 609		zone_page_state(&zones[ZONE_DMA32], item) +
 610#endif
 611#ifdef CONFIG_HIGHMEM
 612		zone_page_state(&zones[ZONE_HIGHMEM], item) +
 
 
 
 
 613#endif
 614		zone_page_state(&zones[ZONE_NORMAL], item) +
 615		zone_page_state(&zones[ZONE_MOVABLE], item);
 616}
 617
 
 
 
 
 
 
 
 618#endif
 619
 620#ifdef CONFIG_COMPACTION
 621
 622struct contig_page_info {
 623	unsigned long free_pages;
 624	unsigned long free_blocks_total;
 625	unsigned long free_blocks_suitable;
 626};
 627
 628/*
 629 * Calculate the number of free pages in a zone, how many contiguous
 630 * pages are free and how many are large enough to satisfy an allocation of
 631 * the target size. Note that this function makes no attempt to estimate
 632 * how many suitable free blocks there *might* be if MOVABLE pages were
 633 * migrated. Calculating that is possible, but expensive and can be
 634 * figured out from userspace
 635 */
 636static void fill_contig_page_info(struct zone *zone,
 637				unsigned int suitable_order,
 638				struct contig_page_info *info)
 639{
 640	unsigned int order;
 641
 642	info->free_pages = 0;
 643	info->free_blocks_total = 0;
 644	info->free_blocks_suitable = 0;
 645
 646	for (order = 0; order < MAX_ORDER; order++) {
 647		unsigned long blocks;
 648
 649		/* Count number of free blocks */
 650		blocks = zone->free_area[order].nr_free;
 651		info->free_blocks_total += blocks;
 652
 653		/* Count free base pages */
 654		info->free_pages += blocks << order;
 655
 656		/* Count the suitable free blocks */
 657		if (order >= suitable_order)
 658			info->free_blocks_suitable += blocks <<
 659						(order - suitable_order);
 660	}
 661}
 662
 663/*
 664 * A fragmentation index only makes sense if an allocation of a requested
 665 * size would fail. If that is true, the fragmentation index indicates
 666 * whether external fragmentation or a lack of memory was the problem.
 667 * The value can be used to determine if page reclaim or compaction
 668 * should be used
 669 */
 670static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 671{
 672	unsigned long requested = 1UL << order;
 673
 
 
 
 674	if (!info->free_blocks_total)
 675		return 0;
 676
 677	/* Fragmentation index only makes sense when a request would fail */
 678	if (info->free_blocks_suitable)
 679		return -1000;
 680
 681	/*
 682	 * Index is between 0 and 1 so return within 3 decimal places
 683	 *
 684	 * 0 => allocation would fail due to lack of memory
 685	 * 1 => allocation would fail due to fragmentation
 686	 */
 687	return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 688}
 689
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 690/* Same as __fragmentation index but allocs contig_page_info on stack */
 691int fragmentation_index(struct zone *zone, unsigned int order)
 692{
 693	struct contig_page_info info;
 694
 695	fill_contig_page_info(zone, order, &info);
 696	return __fragmentation_index(order, &info);
 697}
 698#endif
 699
 700#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 
 701#ifdef CONFIG_ZONE_DMA
 702#define TEXT_FOR_DMA(xx) xx "_dma",
 703#else
 704#define TEXT_FOR_DMA(xx)
 705#endif
 706
 707#ifdef CONFIG_ZONE_DMA32
 708#define TEXT_FOR_DMA32(xx) xx "_dma32",
 709#else
 710#define TEXT_FOR_DMA32(xx)
 711#endif
 712
 713#ifdef CONFIG_HIGHMEM
 714#define TEXT_FOR_HIGHMEM(xx) xx "_high",
 715#else
 716#define TEXT_FOR_HIGHMEM(xx)
 717#endif
 718
 719#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 720					TEXT_FOR_HIGHMEM(xx) xx "_movable",
 721
 722const char * const vmstat_text[] = {
 723	/* enum zone_stat_item countes */
 724	"nr_free_pages",
 725	"nr_alloc_batch",
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 726	"nr_inactive_anon",
 727	"nr_active_anon",
 728	"nr_inactive_file",
 729	"nr_active_file",
 730	"nr_unevictable",
 731	"nr_mlock",
 
 
 
 
 
 
 
 
 
 
 
 732	"nr_anon_pages",
 733	"nr_mapped",
 734	"nr_file_pages",
 735	"nr_dirty",
 736	"nr_writeback",
 737	"nr_slab_reclaimable",
 738	"nr_slab_unreclaimable",
 739	"nr_page_table_pages",
 740	"nr_kernel_stack",
 741	"nr_unstable",
 742	"nr_bounce",
 
 743	"nr_vmscan_write",
 744	"nr_vmscan_immediate_reclaim",
 745	"nr_writeback_temp",
 746	"nr_isolated_anon",
 747	"nr_isolated_file",
 748	"nr_shmem",
 749	"nr_dirtied",
 750	"nr_written",
 751	"nr_pages_scanned",
 752
 753#ifdef CONFIG_NUMA
 754	"numa_hit",
 755	"numa_miss",
 756	"numa_foreign",
 757	"numa_interleave",
 758	"numa_local",
 759	"numa_other",
 760#endif
 761	"workingset_refault",
 762	"workingset_activate",
 763	"workingset_nodereclaim",
 764	"nr_anon_transparent_hugepages",
 765	"nr_free_cma",
 766
 767	/* enum writeback_stat_item counters */
 768	"nr_dirty_threshold",
 769	"nr_dirty_background_threshold",
 770
 771#ifdef CONFIG_VM_EVENT_COUNTERS
 772	/* enum vm_event_item counters */
 773	"pgpgin",
 774	"pgpgout",
 775	"pswpin",
 776	"pswpout",
 777
 778	TEXTS_FOR_ZONES("pgalloc")
 
 
 779
 780	"pgfree",
 781	"pgactivate",
 782	"pgdeactivate",
 
 783
 784	"pgfault",
 785	"pgmajfault",
 786	"pglazyfreed",
 787
 788	TEXTS_FOR_ZONES("pgrefill")
 789	TEXTS_FOR_ZONES("pgsteal_kswapd")
 790	TEXTS_FOR_ZONES("pgsteal_direct")
 791	TEXTS_FOR_ZONES("pgscan_kswapd")
 792	TEXTS_FOR_ZONES("pgscan_direct")
 
 793	"pgscan_direct_throttle",
 
 
 
 
 794
 795#ifdef CONFIG_NUMA
 796	"zone_reclaim_failed",
 797#endif
 798	"pginodesteal",
 799	"slabs_scanned",
 800	"kswapd_inodesteal",
 801	"kswapd_low_wmark_hit_quickly",
 802	"kswapd_high_wmark_hit_quickly",
 803	"pageoutrun",
 804	"allocstall",
 805
 806	"pgrotated",
 807
 808	"drop_pagecache",
 809	"drop_slab",
 
 810
 811#ifdef CONFIG_NUMA_BALANCING
 812	"numa_pte_updates",
 813	"numa_huge_pte_updates",
 814	"numa_hint_faults",
 815	"numa_hint_faults_local",
 816	"numa_pages_migrated",
 817#endif
 818#ifdef CONFIG_MIGRATION
 819	"pgmigrate_success",
 820	"pgmigrate_fail",
 
 
 
 821#endif
 822#ifdef CONFIG_COMPACTION
 823	"compact_migrate_scanned",
 824	"compact_free_scanned",
 825	"compact_isolated",
 826	"compact_stall",
 827	"compact_fail",
 828	"compact_success",
 829	"compact_daemon_wake",
 
 
 830#endif
 831
 832#ifdef CONFIG_HUGETLB_PAGE
 833	"htlb_buddy_alloc_success",
 834	"htlb_buddy_alloc_fail",
 835#endif
 836	"unevictable_pgs_culled",
 837	"unevictable_pgs_scanned",
 838	"unevictable_pgs_rescued",
 839	"unevictable_pgs_mlocked",
 840	"unevictable_pgs_munlocked",
 841	"unevictable_pgs_cleared",
 842	"unevictable_pgs_stranded",
 843
 844#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 845	"thp_fault_alloc",
 846	"thp_fault_fallback",
 
 847	"thp_collapse_alloc",
 848	"thp_collapse_alloc_failed",
 
 
 
 
 849	"thp_split_page",
 850	"thp_split_page_failed",
 851	"thp_deferred_split_page",
 852	"thp_split_pmd",
 
 
 
 853	"thp_zero_page_alloc",
 854	"thp_zero_page_alloc_failed",
 
 
 855#endif
 856#ifdef CONFIG_MEMORY_BALLOON
 857	"balloon_inflate",
 858	"balloon_deflate",
 859#ifdef CONFIG_BALLOON_COMPACTION
 860	"balloon_migrate",
 861#endif
 862#endif /* CONFIG_MEMORY_BALLOON */
 863#ifdef CONFIG_DEBUG_TLBFLUSH
 864#ifdef CONFIG_SMP
 865	"nr_tlb_remote_flush",
 866	"nr_tlb_remote_flush_received",
 867#endif /* CONFIG_SMP */
 868	"nr_tlb_local_flush_all",
 869	"nr_tlb_local_flush_one",
 870#endif /* CONFIG_DEBUG_TLBFLUSH */
 871
 872#ifdef CONFIG_DEBUG_VM_VMACACHE
 873	"vmacache_find_calls",
 874	"vmacache_find_hits",
 875	"vmacache_full_flushes",
 876#endif
 877#endif /* CONFIG_VM_EVENTS_COUNTERS */
 
 
 
 
 878};
 879#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 880
 881
 882#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
 883     defined(CONFIG_PROC_FS)
 884static void *frag_start(struct seq_file *m, loff_t *pos)
 885{
 886	pg_data_t *pgdat;
 887	loff_t node = *pos;
 888
 889	for (pgdat = first_online_pgdat();
 890	     pgdat && node;
 891	     pgdat = next_online_pgdat(pgdat))
 892		--node;
 893
 894	return pgdat;
 895}
 896
 897static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 898{
 899	pg_data_t *pgdat = (pg_data_t *)arg;
 900
 901	(*pos)++;
 902	return next_online_pgdat(pgdat);
 903}
 904
 905static void frag_stop(struct seq_file *m, void *arg)
 906{
 907}
 908
 909/* Walk all the zones in a node and print using a callback */
 
 
 
 910static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 
 911		void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 912{
 913	struct zone *zone;
 914	struct zone *node_zones = pgdat->node_zones;
 915	unsigned long flags;
 916
 917	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 918		if (!populated_zone(zone))
 919			continue;
 920
 921		spin_lock_irqsave(&zone->lock, flags);
 
 922		print(m, pgdat, zone);
 923		spin_unlock_irqrestore(&zone->lock, flags);
 
 924	}
 925}
 926#endif
 927
 928#ifdef CONFIG_PROC_FS
 929static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 930						struct zone *zone)
 931{
 932	int order;
 933
 934	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 935	for (order = 0; order < MAX_ORDER; ++order)
 936		seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 937	seq_putc(m, '\n');
 938}
 939
 940/*
 941 * This walks the free areas for each zone.
 942 */
 943static int frag_show(struct seq_file *m, void *arg)
 944{
 945	pg_data_t *pgdat = (pg_data_t *)arg;
 946	walk_zones_in_node(m, pgdat, frag_show_print);
 947	return 0;
 948}
 949
 950static void pagetypeinfo_showfree_print(struct seq_file *m,
 951					pg_data_t *pgdat, struct zone *zone)
 952{
 953	int order, mtype;
 954
 955	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 956		seq_printf(m, "Node %4d, zone %8s, type %12s ",
 957					pgdat->node_id,
 958					zone->name,
 959					migratetype_names[mtype]);
 960		for (order = 0; order < MAX_ORDER; ++order) {
 961			unsigned long freecount = 0;
 962			struct free_area *area;
 963			struct list_head *curr;
 
 964
 965			area = &(zone->free_area[order]);
 966
 967			list_for_each(curr, &area->free_list[mtype])
 968				freecount++;
 969			seq_printf(m, "%6lu ", freecount);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 970		}
 971		seq_putc(m, '\n');
 972	}
 973}
 974
 975/* Print out the free pages at each order for each migatetype */
 976static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 977{
 978	int order;
 979	pg_data_t *pgdat = (pg_data_t *)arg;
 980
 981	/* Print header */
 982	seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 983	for (order = 0; order < MAX_ORDER; ++order)
 984		seq_printf(m, "%6d ", order);
 985	seq_putc(m, '\n');
 986
 987	walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 988
 989	return 0;
 990}
 991
 992static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 993					pg_data_t *pgdat, struct zone *zone)
 994{
 995	int mtype;
 996	unsigned long pfn;
 997	unsigned long start_pfn = zone->zone_start_pfn;
 998	unsigned long end_pfn = zone_end_pfn(zone);
 999	unsigned long count[MIGRATE_TYPES] = { 0, };
1000
1001	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1002		struct page *page;
1003
1004		if (!pfn_valid(pfn))
 
1005			continue;
1006
1007		page = pfn_to_page(pfn);
1008
1009		/* Watch for unexpected holes punched in the memmap */
1010		if (!memmap_valid_within(pfn, page, zone))
1011			continue;
1012
 
 
 
1013		mtype = get_pageblock_migratetype(page);
1014
1015		if (mtype < MIGRATE_TYPES)
1016			count[mtype]++;
1017	}
1018
1019	/* Print counts */
1020	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1021	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1022		seq_printf(m, "%12lu ", count[mtype]);
1023	seq_putc(m, '\n');
1024}
1025
1026/* Print out the free pages at each order for each migratetype */
1027static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1028{
1029	int mtype;
1030	pg_data_t *pgdat = (pg_data_t *)arg;
1031
1032	seq_printf(m, "\n%-23s", "Number of blocks type ");
1033	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1034		seq_printf(m, "%12s ", migratetype_names[mtype]);
1035	seq_putc(m, '\n');
1036	walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 
1037
1038	return 0;
1039}
1040
1041#ifdef CONFIG_PAGE_OWNER
1042static void pagetypeinfo_showmixedcount_print(struct seq_file *m,
1043							pg_data_t *pgdat,
1044							struct zone *zone)
1045{
1046	struct page *page;
1047	struct page_ext *page_ext;
1048	unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
1049	unsigned long end_pfn = pfn + zone->spanned_pages;
1050	unsigned long count[MIGRATE_TYPES] = { 0, };
1051	int pageblock_mt, page_mt;
1052	int i;
1053
1054	/* Scan block by block. First and last block may be incomplete */
1055	pfn = zone->zone_start_pfn;
1056
1057	/*
1058	 * Walk the zone in pageblock_nr_pages steps. If a page block spans
1059	 * a zone boundary, it will be double counted between zones. This does
1060	 * not matter as the mixed block count will still be correct
1061	 */
1062	for (; pfn < end_pfn; ) {
1063		if (!pfn_valid(pfn)) {
1064			pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
1065			continue;
1066		}
1067
1068		block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
1069		block_end_pfn = min(block_end_pfn, end_pfn);
1070
1071		page = pfn_to_page(pfn);
1072		pageblock_mt = get_pfnblock_migratetype(page, pfn);
1073
1074		for (; pfn < block_end_pfn; pfn++) {
1075			if (!pfn_valid_within(pfn))
1076				continue;
1077
1078			page = pfn_to_page(pfn);
1079			if (PageBuddy(page)) {
1080				pfn += (1UL << page_order(page)) - 1;
1081				continue;
1082			}
1083
1084			if (PageReserved(page))
1085				continue;
1086
1087			page_ext = lookup_page_ext(page);
1088
1089			if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
1090				continue;
1091
1092			page_mt = gfpflags_to_migratetype(page_ext->gfp_mask);
1093			if (pageblock_mt != page_mt) {
1094				if (is_migrate_cma(pageblock_mt))
1095					count[MIGRATE_MOVABLE]++;
1096				else
1097					count[pageblock_mt]++;
1098
1099				pfn = block_end_pfn;
1100				break;
1101			}
1102			pfn += (1UL << page_ext->order) - 1;
1103		}
1104	}
1105
1106	/* Print counts */
1107	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1108	for (i = 0; i < MIGRATE_TYPES; i++)
1109		seq_printf(m, "%12lu ", count[i]);
1110	seq_putc(m, '\n');
1111}
1112#endif /* CONFIG_PAGE_OWNER */
1113
1114/*
1115 * Print out the number of pageblocks for each migratetype that contain pages
1116 * of other types. This gives an indication of how well fallbacks are being
1117 * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1118 * to determine what is going on
1119 */
1120static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1121{
1122#ifdef CONFIG_PAGE_OWNER
1123	int mtype;
1124
1125	if (!static_branch_unlikely(&page_owner_inited))
1126		return;
1127
1128	drain_all_pages(NULL);
1129
1130	seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1131	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1132		seq_printf(m, "%12s ", migratetype_names[mtype]);
1133	seq_putc(m, '\n');
1134
1135	walk_zones_in_node(m, pgdat, pagetypeinfo_showmixedcount_print);
 
1136#endif /* CONFIG_PAGE_OWNER */
1137}
1138
1139/*
1140 * This prints out statistics in relation to grouping pages by mobility.
1141 * It is expensive to collect so do not constantly read the file.
1142 */
1143static int pagetypeinfo_show(struct seq_file *m, void *arg)
1144{
1145	pg_data_t *pgdat = (pg_data_t *)arg;
1146
1147	/* check memoryless node */
1148	if (!node_state(pgdat->node_id, N_MEMORY))
1149		return 0;
1150
1151	seq_printf(m, "Page block order: %d\n", pageblock_order);
1152	seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
1153	seq_putc(m, '\n');
1154	pagetypeinfo_showfree(m, pgdat);
1155	pagetypeinfo_showblockcount(m, pgdat);
1156	pagetypeinfo_showmixedcount(m, pgdat);
1157
1158	return 0;
1159}
1160
1161static const struct seq_operations fragmentation_op = {
1162	.start	= frag_start,
1163	.next	= frag_next,
1164	.stop	= frag_stop,
1165	.show	= frag_show,
1166};
1167
1168static int fragmentation_open(struct inode *inode, struct file *file)
1169{
1170	return seq_open(file, &fragmentation_op);
1171}
1172
1173static const struct file_operations fragmentation_file_operations = {
1174	.open		= fragmentation_open,
1175	.read		= seq_read,
1176	.llseek		= seq_lseek,
1177	.release	= seq_release,
1178};
1179
1180static const struct seq_operations pagetypeinfo_op = {
1181	.start	= frag_start,
1182	.next	= frag_next,
1183	.stop	= frag_stop,
1184	.show	= pagetypeinfo_show,
1185};
1186
1187static int pagetypeinfo_open(struct inode *inode, struct file *file)
1188{
1189	return seq_open(file, &pagetypeinfo_op);
 
 
 
 
 
 
 
 
 
1190}
1191
1192static const struct file_operations pagetypeinfo_file_ops = {
1193	.open		= pagetypeinfo_open,
1194	.read		= seq_read,
1195	.llseek		= seq_lseek,
1196	.release	= seq_release,
1197};
1198
1199static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1200							struct zone *zone)
1201{
1202	int i;
1203	seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
 
 
 
 
 
 
 
1204	seq_printf(m,
1205		   "\n  pages free     %lu"
1206		   "\n        min      %lu"
1207		   "\n        low      %lu"
1208		   "\n        high     %lu"
1209		   "\n        scanned  %lu"
1210		   "\n        spanned  %lu"
1211		   "\n        present  %lu"
1212		   "\n        managed  %lu",
1213		   zone_page_state(zone, NR_FREE_PAGES),
1214		   min_wmark_pages(zone),
1215		   low_wmark_pages(zone),
1216		   high_wmark_pages(zone),
1217		   zone_page_state(zone, NR_PAGES_SCANNED),
1218		   zone->spanned_pages,
1219		   zone->present_pages,
1220		   zone->managed_pages);
1221
1222	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1223		seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
1224				zone_page_state(zone, i));
1225
1226	seq_printf(m,
1227		   "\n        protection: (%ld",
1228		   zone->lowmem_reserve[0]);
1229	for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1230		seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1231	seq_printf(m,
1232		   ")"
1233		   "\n  pagesets");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1234	for_each_online_cpu(i) {
1235		struct per_cpu_pageset *pageset;
1236
1237		pageset = per_cpu_ptr(zone->pageset, i);
1238		seq_printf(m,
1239			   "\n    cpu: %i"
1240			   "\n              count: %i"
1241			   "\n              high:  %i"
1242			   "\n              batch: %i",
1243			   i,
1244			   pageset->pcp.count,
1245			   pageset->pcp.high,
1246			   pageset->pcp.batch);
1247#ifdef CONFIG_SMP
1248		seq_printf(m, "\n  vm stats threshold: %d",
1249				pageset->stat_threshold);
1250#endif
1251	}
1252	seq_printf(m,
1253		   "\n  all_unreclaimable: %u"
1254		   "\n  start_pfn:         %lu"
1255		   "\n  inactive_ratio:    %u",
1256		   !zone_reclaimable(zone),
1257		   zone->zone_start_pfn,
1258		   zone->inactive_ratio);
1259	seq_putc(m, '\n');
1260}
1261
1262/*
1263 * Output information about zones in @pgdat.
 
 
 
1264 */
1265static int zoneinfo_show(struct seq_file *m, void *arg)
1266{
1267	pg_data_t *pgdat = (pg_data_t *)arg;
1268	walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1269	return 0;
1270}
1271
1272static const struct seq_operations zoneinfo_op = {
1273	.start	= frag_start, /* iterate over all zones. The same as in
1274			       * fragmentation. */
1275	.next	= frag_next,
1276	.stop	= frag_stop,
1277	.show	= zoneinfo_show,
1278};
1279
1280static int zoneinfo_open(struct inode *inode, struct file *file)
1281{
1282	return seq_open(file, &zoneinfo_op);
1283}
1284
1285static const struct file_operations proc_zoneinfo_file_operations = {
1286	.open		= zoneinfo_open,
1287	.read		= seq_read,
1288	.llseek		= seq_lseek,
1289	.release	= seq_release,
1290};
1291
1292enum writeback_stat_item {
1293	NR_DIRTY_THRESHOLD,
1294	NR_DIRTY_BG_THRESHOLD,
1295	NR_VM_WRITEBACK_STAT_ITEMS,
1296};
1297
1298static void *vmstat_start(struct seq_file *m, loff_t *pos)
1299{
1300	unsigned long *v;
1301	int i, stat_items_size;
1302
1303	if (*pos >= ARRAY_SIZE(vmstat_text))
1304		return NULL;
1305	stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1306			  NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1307
1308#ifdef CONFIG_VM_EVENT_COUNTERS
1309	stat_items_size += sizeof(struct vm_event_state);
1310#endif
1311
1312	v = kmalloc(stat_items_size, GFP_KERNEL);
 
1313	m->private = v;
1314	if (!v)
1315		return ERR_PTR(-ENOMEM);
1316	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1317		v[i] = global_page_state(i);
1318	v += NR_VM_ZONE_STAT_ITEMS;
1319
 
 
 
 
 
 
 
 
 
 
1320	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1321			    v + NR_DIRTY_THRESHOLD);
1322	v += NR_VM_WRITEBACK_STAT_ITEMS;
1323
1324#ifdef CONFIG_VM_EVENT_COUNTERS
1325	all_vm_events(v);
1326	v[PGPGIN] /= 2;		/* sectors -> kbytes */
1327	v[PGPGOUT] /= 2;
1328#endif
1329	return (unsigned long *)m->private + *pos;
1330}
1331
1332static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1333{
1334	(*pos)++;
1335	if (*pos >= ARRAY_SIZE(vmstat_text))
1336		return NULL;
1337	return (unsigned long *)m->private + *pos;
1338}
1339
1340static int vmstat_show(struct seq_file *m, void *arg)
1341{
1342	unsigned long *l = arg;
1343	unsigned long off = l - (unsigned long *)m->private;
1344
1345	seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
 
 
 
 
 
 
 
 
 
 
1346	return 0;
1347}
1348
1349static void vmstat_stop(struct seq_file *m, void *arg)
1350{
1351	kfree(m->private);
1352	m->private = NULL;
1353}
1354
1355static const struct seq_operations vmstat_op = {
1356	.start	= vmstat_start,
1357	.next	= vmstat_next,
1358	.stop	= vmstat_stop,
1359	.show	= vmstat_show,
1360};
 
1361
1362static int vmstat_open(struct inode *inode, struct file *file)
 
 
 
 
 
1363{
1364	return seq_open(file, &vmstat_op);
1365}
1366
1367static const struct file_operations proc_vmstat_file_operations = {
1368	.open		= vmstat_open,
1369	.read		= seq_read,
1370	.llseek		= seq_lseek,
1371	.release	= seq_release,
1372};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1373#endif /* CONFIG_PROC_FS */
1374
1375#ifdef CONFIG_SMP
1376static struct workqueue_struct *vmstat_wq;
1377static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1378int sysctl_stat_interval __read_mostly = HZ;
1379static cpumask_var_t cpu_stat_off;
1380
1381static void vmstat_update(struct work_struct *w)
1382{
1383	if (refresh_cpu_vm_stats(true)) {
1384		/*
1385		 * Counters were updated so we expect more updates
1386		 * to occur in the future. Keep on running the
1387		 * update worker thread.
1388		 * If we were marked on cpu_stat_off clear the flag
1389		 * so that vmstat_shepherd doesn't schedule us again.
1390		 */
1391		if (!cpumask_test_and_clear_cpu(smp_processor_id(),
1392						cpu_stat_off)) {
1393			queue_delayed_work_on(smp_processor_id(), vmstat_wq,
1394				this_cpu_ptr(&vmstat_work),
1395				round_jiffies_relative(sysctl_stat_interval));
1396		}
1397	} else {
1398		/*
1399		 * We did not update any counters so the app may be in
1400		 * a mode where it does not cause counter updates.
1401		 * We may be uselessly running vmstat_update.
1402		 * Defer the checking for differentials to the
1403		 * shepherd thread on a different processor.
1404		 */
1405		cpumask_set_cpu(smp_processor_id(), cpu_stat_off);
1406	}
1407}
1408
1409/*
1410 * Switch off vmstat processing and then fold all the remaining differentials
1411 * until the diffs stay at zero. The function is used by NOHZ and can only be
1412 * invoked when tick processing is not active.
1413 */
1414/*
1415 * Check if the diffs for a certain cpu indicate that
1416 * an update is needed.
1417 */
1418static bool need_update(int cpu)
1419{
1420	struct zone *zone;
1421
1422	for_each_populated_zone(zone) {
1423		struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu);
1424
1425		BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
 
 
 
 
1426		/*
1427		 * The fast way of checking if there are any vmstat diffs.
1428		 * This works because the diffs are byte sized items.
1429		 */
1430		if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS))
 
1431			return true;
1432
 
 
 
 
1433	}
1434	return false;
1435}
1436
 
 
 
 
 
1437void quiet_vmstat(void)
1438{
1439	if (system_state != SYSTEM_RUNNING)
1440		return;
1441
1442	/*
1443	 * If we are already in hands of the shepherd then there
1444	 * is nothing for us to do here.
1445	 */
1446	if (cpumask_test_and_set_cpu(smp_processor_id(), cpu_stat_off))
1447		return;
1448
1449	if (!need_update(smp_processor_id()))
1450		return;
1451
1452	/*
1453	 * Just refresh counters and do not care about the pending delayed
1454	 * vmstat_update. It doesn't fire that often to matter and canceling
1455	 * it would be too expensive from this path.
1456	 * vmstat_shepherd will take care about that for us.
1457	 */
1458	refresh_cpu_vm_stats(false);
1459}
1460
1461
1462/*
1463 * Shepherd worker thread that checks the
1464 * differentials of processors that have their worker
1465 * threads for vm statistics updates disabled because of
1466 * inactivity.
1467 */
1468static void vmstat_shepherd(struct work_struct *w);
1469
1470static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
1471
1472static void vmstat_shepherd(struct work_struct *w)
1473{
1474	int cpu;
1475
1476	get_online_cpus();
1477	/* Check processors whose vmstat worker threads have been disabled */
1478	for_each_cpu(cpu, cpu_stat_off) {
1479		struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
1480
1481		if (need_update(cpu)) {
1482			if (cpumask_test_and_clear_cpu(cpu, cpu_stat_off))
1483				queue_delayed_work_on(cpu, vmstat_wq, dw, 0);
1484		} else {
1485			/*
1486			 * Cancel the work if quiet_vmstat has put this
1487			 * cpu on cpu_stat_off because the work item might
1488			 * be still scheduled
1489			 */
1490			cancel_delayed_work(dw);
1491		}
1492	}
1493	put_online_cpus();
1494
1495	schedule_delayed_work(&shepherd,
1496		round_jiffies_relative(sysctl_stat_interval));
1497}
1498
1499static void __init start_shepherd_timer(void)
1500{
1501	int cpu;
1502
1503	for_each_possible_cpu(cpu)
1504		INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
1505			vmstat_update);
1506
1507	if (!alloc_cpumask_var(&cpu_stat_off, GFP_KERNEL))
1508		BUG();
1509	cpumask_copy(cpu_stat_off, cpu_online_mask);
1510
1511	vmstat_wq = alloc_workqueue("vmstat", WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
1512	schedule_delayed_work(&shepherd,
1513		round_jiffies_relative(sysctl_stat_interval));
1514}
1515
1516static void vmstat_cpu_dead(int node)
1517{
1518	int cpu;
 
 
 
 
 
 
1519
1520	get_online_cpus();
1521	for_each_online_cpu(cpu)
1522		if (cpu_to_node(cpu) == node)
1523			goto end;
 
 
1524
1525	node_clear_state(node, N_CPU);
1526end:
1527	put_online_cpus();
 
1528}
1529
1530/*
1531 * Use the cpu notifier to insure that the thresholds are recalculated
1532 * when necessary.
1533 */
1534static int vmstat_cpuup_callback(struct notifier_block *nfb,
1535		unsigned long action,
1536		void *hcpu)
1537{
1538	long cpu = (long)hcpu;
1539
1540	switch (action) {
1541	case CPU_ONLINE:
1542	case CPU_ONLINE_FROZEN:
1543		refresh_zone_stat_thresholds();
1544		node_set_state(cpu_to_node(cpu), N_CPU);
1545		cpumask_set_cpu(cpu, cpu_stat_off);
1546		break;
1547	case CPU_DOWN_PREPARE:
1548	case CPU_DOWN_PREPARE_FROZEN:
1549		cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1550		cpumask_clear_cpu(cpu, cpu_stat_off);
1551		break;
1552	case CPU_DOWN_FAILED:
1553	case CPU_DOWN_FAILED_FROZEN:
1554		cpumask_set_cpu(cpu, cpu_stat_off);
1555		break;
1556	case CPU_DEAD:
1557	case CPU_DEAD_FROZEN:
1558		refresh_zone_stat_thresholds();
1559		vmstat_cpu_dead(cpu_to_node(cpu));
1560		break;
1561	default:
1562		break;
1563	}
1564	return NOTIFY_OK;
1565}
1566
1567static struct notifier_block vmstat_notifier =
1568	{ &vmstat_cpuup_callback, NULL, 0 };
1569#endif
1570
1571static int __init setup_vmstat(void)
 
 
1572{
 
 
 
 
1573#ifdef CONFIG_SMP
1574	cpu_notifier_register_begin();
1575	__register_cpu_notifier(&vmstat_notifier);
 
 
 
 
 
 
 
 
 
 
 
 
1576
1577	start_shepherd_timer();
1578	cpu_notifier_register_done();
1579#endif
1580#ifdef CONFIG_PROC_FS
1581	proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1582	proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1583	proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1584	proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1585#endif
1586	return 0;
1587}
1588module_init(setup_vmstat)
1589
1590#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1591
1592/*
1593 * Return an index indicating how much of the available free memory is
1594 * unusable for an allocation of the requested size.
1595 */
1596static int unusable_free_index(unsigned int order,
1597				struct contig_page_info *info)
1598{
1599	/* No free memory is interpreted as all free memory is unusable */
1600	if (info->free_pages == 0)
1601		return 1000;
1602
1603	/*
1604	 * Index should be a value between 0 and 1. Return a value to 3
1605	 * decimal places.
1606	 *
1607	 * 0 => no fragmentation
1608	 * 1 => high fragmentation
1609	 */
1610	return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1611
1612}
1613
1614static void unusable_show_print(struct seq_file *m,
1615					pg_data_t *pgdat, struct zone *zone)
1616{
1617	unsigned int order;
1618	int index;
1619	struct contig_page_info info;
1620
1621	seq_printf(m, "Node %d, zone %8s ",
1622				pgdat->node_id,
1623				zone->name);
1624	for (order = 0; order < MAX_ORDER; ++order) {
1625		fill_contig_page_info(zone, order, &info);
1626		index = unusable_free_index(order, &info);
1627		seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1628	}
1629
1630	seq_putc(m, '\n');
1631}
1632
1633/*
1634 * Display unusable free space index
1635 *
1636 * The unusable free space index measures how much of the available free
1637 * memory cannot be used to satisfy an allocation of a given size and is a
1638 * value between 0 and 1. The higher the value, the more of free memory is
1639 * unusable and by implication, the worse the external fragmentation is. This
1640 * can be expressed as a percentage by multiplying by 100.
1641 */
1642static int unusable_show(struct seq_file *m, void *arg)
1643{
1644	pg_data_t *pgdat = (pg_data_t *)arg;
1645
1646	/* check memoryless node */
1647	if (!node_state(pgdat->node_id, N_MEMORY))
1648		return 0;
1649
1650	walk_zones_in_node(m, pgdat, unusable_show_print);
1651
1652	return 0;
1653}
1654
1655static const struct seq_operations unusable_op = {
1656	.start	= frag_start,
1657	.next	= frag_next,
1658	.stop	= frag_stop,
1659	.show	= unusable_show,
1660};
1661
1662static int unusable_open(struct inode *inode, struct file *file)
1663{
1664	return seq_open(file, &unusable_op);
1665}
1666
1667static const struct file_operations unusable_file_ops = {
1668	.open		= unusable_open,
1669	.read		= seq_read,
1670	.llseek		= seq_lseek,
1671	.release	= seq_release,
1672};
1673
1674static void extfrag_show_print(struct seq_file *m,
1675					pg_data_t *pgdat, struct zone *zone)
1676{
1677	unsigned int order;
1678	int index;
1679
1680	/* Alloc on stack as interrupts are disabled for zone walk */
1681	struct contig_page_info info;
1682
1683	seq_printf(m, "Node %d, zone %8s ",
1684				pgdat->node_id,
1685				zone->name);
1686	for (order = 0; order < MAX_ORDER; ++order) {
1687		fill_contig_page_info(zone, order, &info);
1688		index = __fragmentation_index(order, &info);
1689		seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1690	}
1691
1692	seq_putc(m, '\n');
1693}
1694
1695/*
1696 * Display fragmentation index for orders that allocations would fail for
1697 */
1698static int extfrag_show(struct seq_file *m, void *arg)
1699{
1700	pg_data_t *pgdat = (pg_data_t *)arg;
1701
1702	walk_zones_in_node(m, pgdat, extfrag_show_print);
1703
1704	return 0;
1705}
1706
1707static const struct seq_operations extfrag_op = {
1708	.start	= frag_start,
1709	.next	= frag_next,
1710	.stop	= frag_stop,
1711	.show	= extfrag_show,
1712};
1713
1714static int extfrag_open(struct inode *inode, struct file *file)
1715{
1716	return seq_open(file, &extfrag_op);
1717}
1718
1719static const struct file_operations extfrag_file_ops = {
1720	.open		= extfrag_open,
1721	.read		= seq_read,
1722	.llseek		= seq_lseek,
1723	.release	= seq_release,
1724};
1725
1726static int __init extfrag_debug_init(void)
1727{
1728	struct dentry *extfrag_debug_root;
1729
1730	extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1731	if (!extfrag_debug_root)
1732		return -ENOMEM;
1733
1734	if (!debugfs_create_file("unusable_index", 0444,
1735			extfrag_debug_root, NULL, &unusable_file_ops))
1736		goto fail;
1737
1738	if (!debugfs_create_file("extfrag_index", 0444,
1739			extfrag_debug_root, NULL, &extfrag_file_ops))
1740		goto fail;
1741
1742	return 0;
1743fail:
1744	debugfs_remove_recursive(extfrag_debug_root);
1745	return -ENOMEM;
1746}
1747
1748module_init(extfrag_debug_init);
1749#endif