xref: /linux/mm/vmstat.c (revision 5a0e3ad6af8660be21ca98a971cd00f331318c05)
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  */
11 #include <linux/fs.h>
12 #include <linux/mm.h>
13 #include <linux/err.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/cpu.h>
17 #include <linux/vmstat.h>
18 #include <linux/sched.h>
19 
20 #ifdef CONFIG_VM_EVENT_COUNTERS
21 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
22 EXPORT_PER_CPU_SYMBOL(vm_event_states);
23 
24 static void sum_vm_events(unsigned long *ret, const struct cpumask *cpumask)
25 {
26 	int cpu;
27 	int i;
28 
29 	memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
30 
31 	for_each_cpu(cpu, cpumask) {
32 		struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
33 
34 		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
35 			ret[i] += this->event[i];
36 	}
37 }
38 
39 /*
40  * Accumulate the vm event counters across all CPUs.
41  * The result is unavoidably approximate - it can change
42  * during and after execution of this function.
43 */
44 void all_vm_events(unsigned long *ret)
45 {
46 	get_online_cpus();
47 	sum_vm_events(ret, cpu_online_mask);
48 	put_online_cpus();
49 }
50 EXPORT_SYMBOL_GPL(all_vm_events);
51 
52 #ifdef CONFIG_HOTPLUG
53 /*
54  * Fold the foreign cpu events into our own.
55  *
56  * This is adding to the events on one processor
57  * but keeps the global counts constant.
58  */
59 void vm_events_fold_cpu(int cpu)
60 {
61 	struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
62 	int i;
63 
64 	for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
65 		count_vm_events(i, fold_state->event[i]);
66 		fold_state->event[i] = 0;
67 	}
68 }
69 #endif /* CONFIG_HOTPLUG */
70 
71 #endif /* CONFIG_VM_EVENT_COUNTERS */
72 
73 /*
74  * Manage combined zone based / global counters
75  *
76  * vm_stat contains the global counters
77  */
78 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
79 EXPORT_SYMBOL(vm_stat);
80 
81 #ifdef CONFIG_SMP
82 
83 static int calculate_threshold(struct zone *zone)
84 {
85 	int threshold;
86 	int mem;	/* memory in 128 MB units */
87 
88 	/*
89 	 * The threshold scales with the number of processors and the amount
90 	 * of memory per zone. More memory means that we can defer updates for
91 	 * longer, more processors could lead to more contention.
92  	 * fls() is used to have a cheap way of logarithmic scaling.
93 	 *
94 	 * Some sample thresholds:
95 	 *
96 	 * Threshold	Processors	(fls)	Zonesize	fls(mem+1)
97 	 * ------------------------------------------------------------------
98 	 * 8		1		1	0.9-1 GB	4
99 	 * 16		2		2	0.9-1 GB	4
100 	 * 20 		2		2	1-2 GB		5
101 	 * 24		2		2	2-4 GB		6
102 	 * 28		2		2	4-8 GB		7
103 	 * 32		2		2	8-16 GB		8
104 	 * 4		2		2	<128M		1
105 	 * 30		4		3	2-4 GB		5
106 	 * 48		4		3	8-16 GB		8
107 	 * 32		8		4	1-2 GB		4
108 	 * 32		8		4	0.9-1GB		4
109 	 * 10		16		5	<128M		1
110 	 * 40		16		5	900M		4
111 	 * 70		64		7	2-4 GB		5
112 	 * 84		64		7	4-8 GB		6
113 	 * 108		512		9	4-8 GB		6
114 	 * 125		1024		10	8-16 GB		8
115 	 * 125		1024		10	16-32 GB	9
116 	 */
117 
118 	mem = zone->present_pages >> (27 - PAGE_SHIFT);
119 
120 	threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
121 
122 	/*
123 	 * Maximum threshold is 125
124 	 */
125 	threshold = min(125, threshold);
126 
127 	return threshold;
128 }
129 
130 /*
131  * Refresh the thresholds for each zone.
132  */
133 static void refresh_zone_stat_thresholds(void)
134 {
135 	struct zone *zone;
136 	int cpu;
137 	int threshold;
138 
139 	for_each_populated_zone(zone) {
140 		threshold = calculate_threshold(zone);
141 
142 		for_each_online_cpu(cpu)
143 			per_cpu_ptr(zone->pageset, cpu)->stat_threshold
144 							= threshold;
145 	}
146 }
147 
148 /*
149  * For use when we know that interrupts are disabled.
150  */
151 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
152 				int delta)
153 {
154 	struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
155 
156 	s8 *p = pcp->vm_stat_diff + item;
157 	long x;
158 
159 	x = delta + *p;
160 
161 	if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
162 		zone_page_state_add(x, zone, item);
163 		x = 0;
164 	}
165 	*p = x;
166 }
167 EXPORT_SYMBOL(__mod_zone_page_state);
168 
169 /*
170  * For an unknown interrupt state
171  */
172 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
173 					int delta)
174 {
175 	unsigned long flags;
176 
177 	local_irq_save(flags);
178 	__mod_zone_page_state(zone, item, delta);
179 	local_irq_restore(flags);
180 }
181 EXPORT_SYMBOL(mod_zone_page_state);
182 
183 /*
184  * Optimized increment and decrement functions.
185  *
186  * These are only for a single page and therefore can take a struct page *
187  * argument instead of struct zone *. This allows the inclusion of the code
188  * generated for page_zone(page) into the optimized functions.
189  *
190  * No overflow check is necessary and therefore the differential can be
191  * incremented or decremented in place which may allow the compilers to
192  * generate better code.
193  * The increment or decrement is known and therefore one boundary check can
194  * be omitted.
195  *
196  * NOTE: These functions are very performance sensitive. Change only
197  * with care.
198  *
199  * Some processors have inc/dec instructions that are atomic vs an interrupt.
200  * However, the code must first determine the differential location in a zone
201  * based on the processor number and then inc/dec the counter. There is no
202  * guarantee without disabling preemption that the processor will not change
203  * in between and therefore the atomicity vs. interrupt cannot be exploited
204  * in a useful way here.
205  */
206 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
207 {
208 	struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
209 	s8 *p = pcp->vm_stat_diff + item;
210 
211 	(*p)++;
212 
213 	if (unlikely(*p > pcp->stat_threshold)) {
214 		int overstep = pcp->stat_threshold / 2;
215 
216 		zone_page_state_add(*p + overstep, zone, item);
217 		*p = -overstep;
218 	}
219 }
220 
221 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
222 {
223 	__inc_zone_state(page_zone(page), item);
224 }
225 EXPORT_SYMBOL(__inc_zone_page_state);
226 
227 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
228 {
229 	struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
230 	s8 *p = pcp->vm_stat_diff + item;
231 
232 	(*p)--;
233 
234 	if (unlikely(*p < - pcp->stat_threshold)) {
235 		int overstep = pcp->stat_threshold / 2;
236 
237 		zone_page_state_add(*p - overstep, zone, item);
238 		*p = overstep;
239 	}
240 }
241 
242 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
243 {
244 	__dec_zone_state(page_zone(page), item);
245 }
246 EXPORT_SYMBOL(__dec_zone_page_state);
247 
248 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
249 {
250 	unsigned long flags;
251 
252 	local_irq_save(flags);
253 	__inc_zone_state(zone, item);
254 	local_irq_restore(flags);
255 }
256 
257 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
258 {
259 	unsigned long flags;
260 	struct zone *zone;
261 
262 	zone = page_zone(page);
263 	local_irq_save(flags);
264 	__inc_zone_state(zone, item);
265 	local_irq_restore(flags);
266 }
267 EXPORT_SYMBOL(inc_zone_page_state);
268 
269 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
270 {
271 	unsigned long flags;
272 
273 	local_irq_save(flags);
274 	__dec_zone_page_state(page, item);
275 	local_irq_restore(flags);
276 }
277 EXPORT_SYMBOL(dec_zone_page_state);
278 
279 /*
280  * Update the zone counters for one cpu.
281  *
282  * The cpu specified must be either the current cpu or a processor that
283  * is not online. If it is the current cpu then the execution thread must
284  * be pinned to the current cpu.
285  *
286  * Note that refresh_cpu_vm_stats strives to only access
287  * node local memory. The per cpu pagesets on remote zones are placed
288  * in the memory local to the processor using that pageset. So the
289  * loop over all zones will access a series of cachelines local to
290  * the processor.
291  *
292  * The call to zone_page_state_add updates the cachelines with the
293  * statistics in the remote zone struct as well as the global cachelines
294  * with the global counters. These could cause remote node cache line
295  * bouncing and will have to be only done when necessary.
296  */
297 void refresh_cpu_vm_stats(int cpu)
298 {
299 	struct zone *zone;
300 	int i;
301 	int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
302 
303 	for_each_populated_zone(zone) {
304 		struct per_cpu_pageset *p;
305 
306 		p = per_cpu_ptr(zone->pageset, cpu);
307 
308 		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
309 			if (p->vm_stat_diff[i]) {
310 				unsigned long flags;
311 				int v;
312 
313 				local_irq_save(flags);
314 				v = p->vm_stat_diff[i];
315 				p->vm_stat_diff[i] = 0;
316 				local_irq_restore(flags);
317 				atomic_long_add(v, &zone->vm_stat[i]);
318 				global_diff[i] += v;
319 #ifdef CONFIG_NUMA
320 				/* 3 seconds idle till flush */
321 				p->expire = 3;
322 #endif
323 			}
324 		cond_resched();
325 #ifdef CONFIG_NUMA
326 		/*
327 		 * Deal with draining the remote pageset of this
328 		 * processor
329 		 *
330 		 * Check if there are pages remaining in this pageset
331 		 * if not then there is nothing to expire.
332 		 */
333 		if (!p->expire || !p->pcp.count)
334 			continue;
335 
336 		/*
337 		 * We never drain zones local to this processor.
338 		 */
339 		if (zone_to_nid(zone) == numa_node_id()) {
340 			p->expire = 0;
341 			continue;
342 		}
343 
344 		p->expire--;
345 		if (p->expire)
346 			continue;
347 
348 		if (p->pcp.count)
349 			drain_zone_pages(zone, &p->pcp);
350 #endif
351 	}
352 
353 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
354 		if (global_diff[i])
355 			atomic_long_add(global_diff[i], &vm_stat[i]);
356 }
357 
358 #endif
359 
360 #ifdef CONFIG_NUMA
361 /*
362  * zonelist = the list of zones passed to the allocator
363  * z 	    = the zone from which the allocation occurred.
364  *
365  * Must be called with interrupts disabled.
366  */
367 void zone_statistics(struct zone *preferred_zone, struct zone *z)
368 {
369 	if (z->zone_pgdat == preferred_zone->zone_pgdat) {
370 		__inc_zone_state(z, NUMA_HIT);
371 	} else {
372 		__inc_zone_state(z, NUMA_MISS);
373 		__inc_zone_state(preferred_zone, NUMA_FOREIGN);
374 	}
375 	if (z->node == numa_node_id())
376 		__inc_zone_state(z, NUMA_LOCAL);
377 	else
378 		__inc_zone_state(z, NUMA_OTHER);
379 }
380 #endif
381 
382 #ifdef CONFIG_PROC_FS
383 #include <linux/proc_fs.h>
384 #include <linux/seq_file.h>
385 
386 static char * const migratetype_names[MIGRATE_TYPES] = {
387 	"Unmovable",
388 	"Reclaimable",
389 	"Movable",
390 	"Reserve",
391 	"Isolate",
392 };
393 
394 static void *frag_start(struct seq_file *m, loff_t *pos)
395 {
396 	pg_data_t *pgdat;
397 	loff_t node = *pos;
398 	for (pgdat = first_online_pgdat();
399 	     pgdat && node;
400 	     pgdat = next_online_pgdat(pgdat))
401 		--node;
402 
403 	return pgdat;
404 }
405 
406 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
407 {
408 	pg_data_t *pgdat = (pg_data_t *)arg;
409 
410 	(*pos)++;
411 	return next_online_pgdat(pgdat);
412 }
413 
414 static void frag_stop(struct seq_file *m, void *arg)
415 {
416 }
417 
418 /* Walk all the zones in a node and print using a callback */
419 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
420 		void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
421 {
422 	struct zone *zone;
423 	struct zone *node_zones = pgdat->node_zones;
424 	unsigned long flags;
425 
426 	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
427 		if (!populated_zone(zone))
428 			continue;
429 
430 		spin_lock_irqsave(&zone->lock, flags);
431 		print(m, pgdat, zone);
432 		spin_unlock_irqrestore(&zone->lock, flags);
433 	}
434 }
435 
436 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
437 						struct zone *zone)
438 {
439 	int order;
440 
441 	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
442 	for (order = 0; order < MAX_ORDER; ++order)
443 		seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
444 	seq_putc(m, '\n');
445 }
446 
447 /*
448  * This walks the free areas for each zone.
449  */
450 static int frag_show(struct seq_file *m, void *arg)
451 {
452 	pg_data_t *pgdat = (pg_data_t *)arg;
453 	walk_zones_in_node(m, pgdat, frag_show_print);
454 	return 0;
455 }
456 
457 static void pagetypeinfo_showfree_print(struct seq_file *m,
458 					pg_data_t *pgdat, struct zone *zone)
459 {
460 	int order, mtype;
461 
462 	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
463 		seq_printf(m, "Node %4d, zone %8s, type %12s ",
464 					pgdat->node_id,
465 					zone->name,
466 					migratetype_names[mtype]);
467 		for (order = 0; order < MAX_ORDER; ++order) {
468 			unsigned long freecount = 0;
469 			struct free_area *area;
470 			struct list_head *curr;
471 
472 			area = &(zone->free_area[order]);
473 
474 			list_for_each(curr, &area->free_list[mtype])
475 				freecount++;
476 			seq_printf(m, "%6lu ", freecount);
477 		}
478 		seq_putc(m, '\n');
479 	}
480 }
481 
482 /* Print out the free pages at each order for each migatetype */
483 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
484 {
485 	int order;
486 	pg_data_t *pgdat = (pg_data_t *)arg;
487 
488 	/* Print header */
489 	seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
490 	for (order = 0; order < MAX_ORDER; ++order)
491 		seq_printf(m, "%6d ", order);
492 	seq_putc(m, '\n');
493 
494 	walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
495 
496 	return 0;
497 }
498 
499 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
500 					pg_data_t *pgdat, struct zone *zone)
501 {
502 	int mtype;
503 	unsigned long pfn;
504 	unsigned long start_pfn = zone->zone_start_pfn;
505 	unsigned long end_pfn = start_pfn + zone->spanned_pages;
506 	unsigned long count[MIGRATE_TYPES] = { 0, };
507 
508 	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
509 		struct page *page;
510 
511 		if (!pfn_valid(pfn))
512 			continue;
513 
514 		page = pfn_to_page(pfn);
515 
516 		/* Watch for unexpected holes punched in the memmap */
517 		if (!memmap_valid_within(pfn, page, zone))
518 			continue;
519 
520 		mtype = get_pageblock_migratetype(page);
521 
522 		if (mtype < MIGRATE_TYPES)
523 			count[mtype]++;
524 	}
525 
526 	/* Print counts */
527 	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
528 	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
529 		seq_printf(m, "%12lu ", count[mtype]);
530 	seq_putc(m, '\n');
531 }
532 
533 /* Print out the free pages at each order for each migratetype */
534 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
535 {
536 	int mtype;
537 	pg_data_t *pgdat = (pg_data_t *)arg;
538 
539 	seq_printf(m, "\n%-23s", "Number of blocks type ");
540 	for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
541 		seq_printf(m, "%12s ", migratetype_names[mtype]);
542 	seq_putc(m, '\n');
543 	walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
544 
545 	return 0;
546 }
547 
548 /*
549  * This prints out statistics in relation to grouping pages by mobility.
550  * It is expensive to collect so do not constantly read the file.
551  */
552 static int pagetypeinfo_show(struct seq_file *m, void *arg)
553 {
554 	pg_data_t *pgdat = (pg_data_t *)arg;
555 
556 	/* check memoryless node */
557 	if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
558 		return 0;
559 
560 	seq_printf(m, "Page block order: %d\n", pageblock_order);
561 	seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
562 	seq_putc(m, '\n');
563 	pagetypeinfo_showfree(m, pgdat);
564 	pagetypeinfo_showblockcount(m, pgdat);
565 
566 	return 0;
567 }
568 
569 static const struct seq_operations fragmentation_op = {
570 	.start	= frag_start,
571 	.next	= frag_next,
572 	.stop	= frag_stop,
573 	.show	= frag_show,
574 };
575 
576 static int fragmentation_open(struct inode *inode, struct file *file)
577 {
578 	return seq_open(file, &fragmentation_op);
579 }
580 
581 static const struct file_operations fragmentation_file_operations = {
582 	.open		= fragmentation_open,
583 	.read		= seq_read,
584 	.llseek		= seq_lseek,
585 	.release	= seq_release,
586 };
587 
588 static const struct seq_operations pagetypeinfo_op = {
589 	.start	= frag_start,
590 	.next	= frag_next,
591 	.stop	= frag_stop,
592 	.show	= pagetypeinfo_show,
593 };
594 
595 static int pagetypeinfo_open(struct inode *inode, struct file *file)
596 {
597 	return seq_open(file, &pagetypeinfo_op);
598 }
599 
600 static const struct file_operations pagetypeinfo_file_ops = {
601 	.open		= pagetypeinfo_open,
602 	.read		= seq_read,
603 	.llseek		= seq_lseek,
604 	.release	= seq_release,
605 };
606 
607 #ifdef CONFIG_ZONE_DMA
608 #define TEXT_FOR_DMA(xx) xx "_dma",
609 #else
610 #define TEXT_FOR_DMA(xx)
611 #endif
612 
613 #ifdef CONFIG_ZONE_DMA32
614 #define TEXT_FOR_DMA32(xx) xx "_dma32",
615 #else
616 #define TEXT_FOR_DMA32(xx)
617 #endif
618 
619 #ifdef CONFIG_HIGHMEM
620 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
621 #else
622 #define TEXT_FOR_HIGHMEM(xx)
623 #endif
624 
625 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
626 					TEXT_FOR_HIGHMEM(xx) xx "_movable",
627 
628 static const char * const vmstat_text[] = {
629 	/* Zoned VM counters */
630 	"nr_free_pages",
631 	"nr_inactive_anon",
632 	"nr_active_anon",
633 	"nr_inactive_file",
634 	"nr_active_file",
635 	"nr_unevictable",
636 	"nr_mlock",
637 	"nr_anon_pages",
638 	"nr_mapped",
639 	"nr_file_pages",
640 	"nr_dirty",
641 	"nr_writeback",
642 	"nr_slab_reclaimable",
643 	"nr_slab_unreclaimable",
644 	"nr_page_table_pages",
645 	"nr_kernel_stack",
646 	"nr_unstable",
647 	"nr_bounce",
648 	"nr_vmscan_write",
649 	"nr_writeback_temp",
650 	"nr_isolated_anon",
651 	"nr_isolated_file",
652 	"nr_shmem",
653 #ifdef CONFIG_NUMA
654 	"numa_hit",
655 	"numa_miss",
656 	"numa_foreign",
657 	"numa_interleave",
658 	"numa_local",
659 	"numa_other",
660 #endif
661 
662 #ifdef CONFIG_VM_EVENT_COUNTERS
663 	"pgpgin",
664 	"pgpgout",
665 	"pswpin",
666 	"pswpout",
667 
668 	TEXTS_FOR_ZONES("pgalloc")
669 
670 	"pgfree",
671 	"pgactivate",
672 	"pgdeactivate",
673 
674 	"pgfault",
675 	"pgmajfault",
676 
677 	TEXTS_FOR_ZONES("pgrefill")
678 	TEXTS_FOR_ZONES("pgsteal")
679 	TEXTS_FOR_ZONES("pgscan_kswapd")
680 	TEXTS_FOR_ZONES("pgscan_direct")
681 
682 #ifdef CONFIG_NUMA
683 	"zone_reclaim_failed",
684 #endif
685 	"pginodesteal",
686 	"slabs_scanned",
687 	"kswapd_steal",
688 	"kswapd_inodesteal",
689 	"kswapd_low_wmark_hit_quickly",
690 	"kswapd_high_wmark_hit_quickly",
691 	"kswapd_skip_congestion_wait",
692 	"pageoutrun",
693 	"allocstall",
694 
695 	"pgrotated",
696 #ifdef CONFIG_HUGETLB_PAGE
697 	"htlb_buddy_alloc_success",
698 	"htlb_buddy_alloc_fail",
699 #endif
700 	"unevictable_pgs_culled",
701 	"unevictable_pgs_scanned",
702 	"unevictable_pgs_rescued",
703 	"unevictable_pgs_mlocked",
704 	"unevictable_pgs_munlocked",
705 	"unevictable_pgs_cleared",
706 	"unevictable_pgs_stranded",
707 	"unevictable_pgs_mlockfreed",
708 #endif
709 };
710 
711 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
712 							struct zone *zone)
713 {
714 	int i;
715 	seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
716 	seq_printf(m,
717 		   "\n  pages free     %lu"
718 		   "\n        min      %lu"
719 		   "\n        low      %lu"
720 		   "\n        high     %lu"
721 		   "\n        scanned  %lu"
722 		   "\n        spanned  %lu"
723 		   "\n        present  %lu",
724 		   zone_page_state(zone, NR_FREE_PAGES),
725 		   min_wmark_pages(zone),
726 		   low_wmark_pages(zone),
727 		   high_wmark_pages(zone),
728 		   zone->pages_scanned,
729 		   zone->spanned_pages,
730 		   zone->present_pages);
731 
732 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
733 		seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
734 				zone_page_state(zone, i));
735 
736 	seq_printf(m,
737 		   "\n        protection: (%lu",
738 		   zone->lowmem_reserve[0]);
739 	for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
740 		seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
741 	seq_printf(m,
742 		   ")"
743 		   "\n  pagesets");
744 	for_each_online_cpu(i) {
745 		struct per_cpu_pageset *pageset;
746 
747 		pageset = per_cpu_ptr(zone->pageset, i);
748 		seq_printf(m,
749 			   "\n    cpu: %i"
750 			   "\n              count: %i"
751 			   "\n              high:  %i"
752 			   "\n              batch: %i",
753 			   i,
754 			   pageset->pcp.count,
755 			   pageset->pcp.high,
756 			   pageset->pcp.batch);
757 #ifdef CONFIG_SMP
758 		seq_printf(m, "\n  vm stats threshold: %d",
759 				pageset->stat_threshold);
760 #endif
761 	}
762 	seq_printf(m,
763 		   "\n  all_unreclaimable: %u"
764 		   "\n  prev_priority:     %i"
765 		   "\n  start_pfn:         %lu"
766 		   "\n  inactive_ratio:    %u",
767 		   zone->all_unreclaimable,
768 		   zone->prev_priority,
769 		   zone->zone_start_pfn,
770 		   zone->inactive_ratio);
771 	seq_putc(m, '\n');
772 }
773 
774 /*
775  * Output information about zones in @pgdat.
776  */
777 static int zoneinfo_show(struct seq_file *m, void *arg)
778 {
779 	pg_data_t *pgdat = (pg_data_t *)arg;
780 	walk_zones_in_node(m, pgdat, zoneinfo_show_print);
781 	return 0;
782 }
783 
784 static const struct seq_operations zoneinfo_op = {
785 	.start	= frag_start, /* iterate over all zones. The same as in
786 			       * fragmentation. */
787 	.next	= frag_next,
788 	.stop	= frag_stop,
789 	.show	= zoneinfo_show,
790 };
791 
792 static int zoneinfo_open(struct inode *inode, struct file *file)
793 {
794 	return seq_open(file, &zoneinfo_op);
795 }
796 
797 static const struct file_operations proc_zoneinfo_file_operations = {
798 	.open		= zoneinfo_open,
799 	.read		= seq_read,
800 	.llseek		= seq_lseek,
801 	.release	= seq_release,
802 };
803 
804 static void *vmstat_start(struct seq_file *m, loff_t *pos)
805 {
806 	unsigned long *v;
807 #ifdef CONFIG_VM_EVENT_COUNTERS
808 	unsigned long *e;
809 #endif
810 	int i;
811 
812 	if (*pos >= ARRAY_SIZE(vmstat_text))
813 		return NULL;
814 
815 #ifdef CONFIG_VM_EVENT_COUNTERS
816 	v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
817 			+ sizeof(struct vm_event_state), GFP_KERNEL);
818 #else
819 	v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long),
820 			GFP_KERNEL);
821 #endif
822 	m->private = v;
823 	if (!v)
824 		return ERR_PTR(-ENOMEM);
825 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
826 		v[i] = global_page_state(i);
827 #ifdef CONFIG_VM_EVENT_COUNTERS
828 	e = v + NR_VM_ZONE_STAT_ITEMS;
829 	all_vm_events(e);
830 	e[PGPGIN] /= 2;		/* sectors -> kbytes */
831 	e[PGPGOUT] /= 2;
832 #endif
833 	return v + *pos;
834 }
835 
836 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
837 {
838 	(*pos)++;
839 	if (*pos >= ARRAY_SIZE(vmstat_text))
840 		return NULL;
841 	return (unsigned long *)m->private + *pos;
842 }
843 
844 static int vmstat_show(struct seq_file *m, void *arg)
845 {
846 	unsigned long *l = arg;
847 	unsigned long off = l - (unsigned long *)m->private;
848 
849 	seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
850 	return 0;
851 }
852 
853 static void vmstat_stop(struct seq_file *m, void *arg)
854 {
855 	kfree(m->private);
856 	m->private = NULL;
857 }
858 
859 static const struct seq_operations vmstat_op = {
860 	.start	= vmstat_start,
861 	.next	= vmstat_next,
862 	.stop	= vmstat_stop,
863 	.show	= vmstat_show,
864 };
865 
866 static int vmstat_open(struct inode *inode, struct file *file)
867 {
868 	return seq_open(file, &vmstat_op);
869 }
870 
871 static const struct file_operations proc_vmstat_file_operations = {
872 	.open		= vmstat_open,
873 	.read		= seq_read,
874 	.llseek		= seq_lseek,
875 	.release	= seq_release,
876 };
877 #endif /* CONFIG_PROC_FS */
878 
879 #ifdef CONFIG_SMP
880 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
881 int sysctl_stat_interval __read_mostly = HZ;
882 
883 static void vmstat_update(struct work_struct *w)
884 {
885 	refresh_cpu_vm_stats(smp_processor_id());
886 	schedule_delayed_work(&__get_cpu_var(vmstat_work),
887 		round_jiffies_relative(sysctl_stat_interval));
888 }
889 
890 static void __cpuinit start_cpu_timer(int cpu)
891 {
892 	struct delayed_work *work = &per_cpu(vmstat_work, cpu);
893 
894 	INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
895 	schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
896 }
897 
898 /*
899  * Use the cpu notifier to insure that the thresholds are recalculated
900  * when necessary.
901  */
902 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
903 		unsigned long action,
904 		void *hcpu)
905 {
906 	long cpu = (long)hcpu;
907 
908 	switch (action) {
909 	case CPU_ONLINE:
910 	case CPU_ONLINE_FROZEN:
911 		start_cpu_timer(cpu);
912 		node_set_state(cpu_to_node(cpu), N_CPU);
913 		break;
914 	case CPU_DOWN_PREPARE:
915 	case CPU_DOWN_PREPARE_FROZEN:
916 		cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
917 		per_cpu(vmstat_work, cpu).work.func = NULL;
918 		break;
919 	case CPU_DOWN_FAILED:
920 	case CPU_DOWN_FAILED_FROZEN:
921 		start_cpu_timer(cpu);
922 		break;
923 	case CPU_DEAD:
924 	case CPU_DEAD_FROZEN:
925 		refresh_zone_stat_thresholds();
926 		break;
927 	default:
928 		break;
929 	}
930 	return NOTIFY_OK;
931 }
932 
933 static struct notifier_block __cpuinitdata vmstat_notifier =
934 	{ &vmstat_cpuup_callback, NULL, 0 };
935 #endif
936 
937 static int __init setup_vmstat(void)
938 {
939 #ifdef CONFIG_SMP
940 	int cpu;
941 
942 	refresh_zone_stat_thresholds();
943 	register_cpu_notifier(&vmstat_notifier);
944 
945 	for_each_online_cpu(cpu)
946 		start_cpu_timer(cpu);
947 #endif
948 #ifdef CONFIG_PROC_FS
949 	proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
950 	proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
951 	proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
952 	proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
953 #endif
954 	return 0;
955 }
956 module_init(setup_vmstat)
957