[linux.git] / mm / page_owner.c

#include <linux/debugfs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/bootmem.h>
#include <linux/stacktrace.h>
#include <linux/page_owner.h>
#include <linux/jump_label.h>
#include <linux/migrate.h>
#include <linux/stackdepot.h>
#include <linux/seq_file.h>

#include "internal.h"

/*
 * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
 * to use off stack temporal storage
 */
#define PAGE_OWNER_STACK_DEPTH (16)

struct page_owner {
	unsigned int order;
	gfp_t gfp_mask;
	int last_migrate_reason;
	depot_stack_handle_t handle;
};

static bool page_owner_disabled = true;
DEFINE_STATIC_KEY_FALSE(page_owner_inited);

static depot_stack_handle_t dummy_handle;
static depot_stack_handle_t failure_handle;

static void init_early_allocated_pages(void);

static int early_page_owner_param(char *buf)
{
	if (!buf)
		return -EINVAL;

	if (strcmp(buf, "on") == 0)
		page_owner_disabled = false;

	return 0;
}
early_param("page_owner", early_page_owner_param);

static bool need_page_owner(void)
{
	if (page_owner_disabled)
		return false;

	return true;
}

static noinline void register_dummy_stack(void)
{
	unsigned long entries[4];
	struct stack_trace dummy;

	dummy.nr_entries = 0;
	dummy.max_entries = ARRAY_SIZE(entries);
	dummy.entries = &entries[0];
	dummy.skip = 0;

	save_stack_trace(&dummy);
	dummy_handle = depot_save_stack(&dummy, GFP_KERNEL);
}

static noinline void register_failure_stack(void)
{
	unsigned long entries[4];
	struct stack_trace failure;

	failure.nr_entries = 0;
	failure.max_entries = ARRAY_SIZE(entries);
	failure.entries = &entries[0];
	failure.skip = 0;

	save_stack_trace(&failure);
	failure_handle = depot_save_stack(&failure, GFP_KERNEL);
}

static void init_page_owner(void)
{
	if (page_owner_disabled)
		return;

	register_dummy_stack();
	register_failure_stack();
	static_branch_enable(&page_owner_inited);
	init_early_allocated_pages();
}

struct page_ext_operations page_owner_ops = {
	.size = sizeof(struct page_owner),
	.need = need_page_owner,
	.init = init_page_owner,
};

static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
{
	return (void *)page_ext + page_owner_ops.offset;
}

void __reset_page_owner(struct page *page, unsigned int order)
{
	int i;
	struct page_ext *page_ext;

	for (i = 0; i < (1 << order); i++) {
		page_ext = lookup_page_ext(page + i);
		if (unlikely(!page_ext))
			continue;
		__clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
	}
}

static inline bool check_recursive_alloc(struct stack_trace *trace,
					unsigned long ip)
{
	int i, count;

	if (!trace->nr_entries)
		return false;

	for (i = 0, count = 0; i < trace->nr_entries; i++) {
		if (trace->entries[i] == ip && ++count == 2)
			return true;
	}

	return false;
}

static noinline depot_stack_handle_t save_stack(gfp_t flags)
{
	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
	struct stack_trace trace = {
		.nr_entries = 0,
		.entries = entries,
		.max_entries = PAGE_OWNER_STACK_DEPTH,
		.skip = 0
	};
	depot_stack_handle_t handle;

	save_stack_trace(&trace);
	if (trace.nr_entries != 0 &&
	    trace.entries[trace.nr_entries-1] == ULONG_MAX)
		trace.nr_entries--;

	/*
	 * We need to check recursion here because our request to stackdepot
	 * could trigger memory allocation to save new entry. New memory
	 * allocation would reach here and call depot_save_stack() again
	 * if we don't catch it. There is still not enough memory in stackdepot
	 * so it would try to allocate memory again and loop forever.
	 */
	if (check_recursive_alloc(&trace, _RET_IP_))
		return dummy_handle;

	handle = depot_save_stack(&trace, flags);
	if (!handle)
		handle = failure_handle;

	return handle;
}

noinline void __set_page_owner(struct page *page, unsigned int order,
					gfp_t gfp_mask)
{
	struct page_ext *page_ext = lookup_page_ext(page);
	struct page_owner *page_owner;

	if (unlikely(!page_ext))
		return;

	page_owner = get_page_owner(page_ext);
	page_owner->handle = save_stack(gfp_mask);
	page_owner->order = order;
	page_owner->gfp_mask = gfp_mask;
	page_owner->last_migrate_reason = -1;

	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
}

void __set_page_owner_migrate_reason(struct page *page, int reason)
{
	struct page_ext *page_ext = lookup_page_ext(page);
	struct page_owner *page_owner;

	if (unlikely(!page_ext))
		return;

	page_owner = get_page_owner(page_ext);
	page_owner->last_migrate_reason = reason;
}

void __split_page_owner(struct page *page, unsigned int order)
{
	int i;
	struct page_ext *page_ext = lookup_page_ext(page);
	struct page_owner *page_owner;

	if (unlikely(!page_ext))
		return;

	page_owner = get_page_owner(page_ext);
	page_owner->order = 0;
	for (i = 1; i < (1 << order); i++)
		__copy_page_owner(page, page + i);
}

void __copy_page_owner(struct page *oldpage, struct page *newpage)
{
	struct page_ext *old_ext = lookup_page_ext(oldpage);
	struct page_ext *new_ext = lookup_page_ext(newpage);
	struct page_owner *old_page_owner, *new_page_owner;

	if (unlikely(!old_ext || !new_ext))
		return;

	old_page_owner = get_page_owner(old_ext);
	new_page_owner = get_page_owner(new_ext);
	new_page_owner->order = old_page_owner->order;
	new_page_owner->gfp_mask = old_page_owner->gfp_mask;
	new_page_owner->last_migrate_reason =
		old_page_owner->last_migrate_reason;
	new_page_owner->handle = old_page_owner->handle;

	/*
	 * We don't clear the bit on the oldpage as it's going to be freed
	 * after migration. Until then, the info can be useful in case of
	 * a bug, and the overal stats will be off a bit only temporarily.
	 * Also, migrate_misplaced_transhuge_page() can still fail the
	 * migration and then we want the oldpage to retain the info. But
	 * in that case we also don't need to explicitly clear the info from
	 * the new page, which will be freed.
	 */
	__set_bit(PAGE_EXT_OWNER, &new_ext->flags);
}

void pagetypeinfo_showmixedcount_print(struct seq_file *m,
				       pg_data_t *pgdat, struct zone *zone)
{
	struct page *page;
	struct page_ext *page_ext;
	struct page_owner *page_owner;
	unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
	unsigned long end_pfn = pfn + zone->spanned_pages;
	unsigned long count[MIGRATE_TYPES] = { 0, };
	int pageblock_mt, page_mt;
	int i;

	/* Scan block by block. First and last block may be incomplete */
	pfn = zone->zone_start_pfn;

	/*
	 * Walk the zone in pageblock_nr_pages steps. If a page block spans
	 * a zone boundary, it will be double counted between zones. This does
	 * not matter as the mixed block count will still be correct
	 */
	for (; pfn < end_pfn; ) {
		if (!pfn_valid(pfn)) {
			pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
			continue;
		}

		block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
		block_end_pfn = min(block_end_pfn, end_pfn);

		page = pfn_to_page(pfn);
		pageblock_mt = get_pageblock_migratetype(page);

		for (; pfn < block_end_pfn; pfn++) {
			if (!pfn_valid_within(pfn))
				continue;

			page = pfn_to_page(pfn);

			if (page_zone(page) != zone)
				continue;

			if (PageBuddy(page)) {
				pfn += (1UL << page_order(page)) - 1;
				continue;
			}

			if (PageReserved(page))
				continue;

			page_ext = lookup_page_ext(page);
			if (unlikely(!page_ext))
				continue;

			if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
				continue;

			page_owner = get_page_owner(page_ext);
			page_mt = gfpflags_to_migratetype(
					page_owner->gfp_mask);
			if (pageblock_mt != page_mt) {
				if (is_migrate_cma(pageblock_mt))
					count[MIGRATE_MOVABLE]++;
				else
					count[pageblock_mt]++;

				pfn = block_end_pfn;
				break;
			}
			pfn += (1UL << page_owner->order) - 1;
		}
	}

	/* Print counts */
	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
	for (i = 0; i < MIGRATE_TYPES; i++)
		seq_printf(m, "%12lu ", count[i]);
	seq_putc(m, '\n');
}

static ssize_t
print_page_owner(char __user *buf, size_t count, unsigned long pfn,
		struct page *page, struct page_owner *page_owner,
		depot_stack_handle_t handle)
{
	int ret;
	int pageblock_mt, page_mt;
	char *kbuf;
	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
	struct stack_trace trace = {
		.nr_entries = 0,
		.entries = entries,
		.max_entries = PAGE_OWNER_STACK_DEPTH,
		.skip = 0
	};

	kbuf = kmalloc(count, GFP_KERNEL);
	if (!kbuf)
		return -ENOMEM;

	ret = snprintf(kbuf, count,
			"Page allocated via order %u, mask %#x(%pGg)\n",
			page_owner->order, page_owner->gfp_mask,
			&page_owner->gfp_mask);

	if (ret >= count)
		goto err;

	/* Print information relevant to grouping pages by mobility */
	pageblock_mt = get_pageblock_migratetype(page);
	page_mt  = gfpflags_to_migratetype(page_owner->gfp_mask);
	ret += snprintf(kbuf + ret, count - ret,
			"PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
			pfn,
			migratetype_names[page_mt],
			pfn >> pageblock_order,
			migratetype_names[pageblock_mt],
			page->flags, &page->flags);

	if (ret >= count)
		goto err;

	depot_fetch_stack(handle, &trace);
	ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
	if (ret >= count)
		goto err;

	if (page_owner->last_migrate_reason != -1) {
		ret += snprintf(kbuf + ret, count - ret,
			"Page has been migrated, last migrate reason: %s\n",
			migrate_reason_names[page_owner->last_migrate_reason]);
		if (ret >= count)
			goto err;
	}

	ret += snprintf(kbuf + ret, count - ret, "\n");
	if (ret >= count)
		goto err;

	if (copy_to_user(buf, kbuf, ret))
		ret = -EFAULT;

	kfree(kbuf);
	return ret;

err:
	kfree(kbuf);
	return -ENOMEM;
}

void __dump_page_owner(struct page *page)
{
	struct page_ext *page_ext = lookup_page_ext(page);
	struct page_owner *page_owner;
	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
	struct stack_trace trace = {
		.nr_entries = 0,
		.entries = entries,
		.max_entries = PAGE_OWNER_STACK_DEPTH,
		.skip = 0
	};
	depot_stack_handle_t handle;
	gfp_t gfp_mask;
	int mt;

	if (unlikely(!page_ext)) {
		pr_alert("There is not page extension available.\n");
		return;
	}

	page_owner = get_page_owner(page_ext);
	gfp_mask = page_owner->gfp_mask;
	mt = gfpflags_to_migratetype(gfp_mask);

	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
		pr_alert("page_owner info is not active (free page?)\n");
		return;
	}

	handle = READ_ONCE(page_owner->handle);
	if (!handle) {
		pr_alert("page_owner info is not active (free page?)\n");
		return;
	}

	depot_fetch_stack(handle, &trace);
	pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
		 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
	print_stack_trace(&trace, 0);

	if (page_owner->last_migrate_reason != -1)
		pr_alert("page has been migrated, last migrate reason: %s\n",
			migrate_reason_names[page_owner->last_migrate_reason]);
}

static ssize_t
read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
	unsigned long pfn;
	struct page *page;
	struct page_ext *page_ext;
	struct page_owner *page_owner;
	depot_stack_handle_t handle;

	if (!static_branch_unlikely(&page_owner_inited))
		return -EINVAL;

	page = NULL;
	pfn = min_low_pfn + *ppos;

	/* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
	while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
		pfn++;

	drain_all_pages(NULL);

	/* Find an allocated page */
	for (; pfn < max_pfn; pfn++) {
		/*
		 * If the new page is in a new MAX_ORDER_NR_PAGES area,
		 * validate the area as existing, skip it if not
		 */
		if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
			pfn += MAX_ORDER_NR_PAGES - 1;
			continue;
		}

		/* Check for holes within a MAX_ORDER area */
		if (!pfn_valid_within(pfn))
			continue;

		page = pfn_to_page(pfn);
		if (PageBuddy(page)) {
			unsigned long freepage_order = page_order_unsafe(page);

			if (freepage_order < MAX_ORDER)
				pfn += (1UL << freepage_order) - 1;
			continue;
		}

		page_ext = lookup_page_ext(page);
		if (unlikely(!page_ext))
			continue;

		/*
		 * Some pages could be missed by concurrent allocation or free,
		 * because we don't hold the zone lock.
		 */
		if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
			continue;

		page_owner = get_page_owner(page_ext);

		/*
		 * Access to page_ext->handle isn't synchronous so we should
		 * be careful to access it.
		 */
		handle = READ_ONCE(page_owner->handle);
		if (!handle)
			continue;

		/* Record the next PFN to read in the file offset */
		*ppos = (pfn - min_low_pfn) + 1;

		return print_page_owner(buf, count, pfn, page,
				page_owner, handle);
	}

	return 0;
}

static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
{
	struct page *page;
	struct page_ext *page_ext;
	unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
	unsigned long end_pfn = pfn + zone->spanned_pages;
	unsigned long count = 0;

	/* Scan block by block. First and last block may be incomplete */
	pfn = zone->zone_start_pfn;

	/*
	 * Walk the zone in pageblock_nr_pages steps. If a page block spans
	 * a zone boundary, it will be double counted between zones. This does
	 * not matter as the mixed block count will still be correct
	 */
	for (; pfn < end_pfn; ) {
		if (!pfn_valid(pfn)) {
			pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
			continue;
		}

		block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
		block_end_pfn = min(block_end_pfn, end_pfn);

		page = pfn_to_page(pfn);

		for (; pfn < block_end_pfn; pfn++) {
			if (!pfn_valid_within(pfn))
				continue;

			page = pfn_to_page(pfn);

			if (page_zone(page) != zone)
				continue;

			/*
			 * We are safe to check buddy flag and order, because
			 * this is init stage and only single thread runs.
			 */
			if (PageBuddy(page)) {
				pfn += (1UL << page_order(page)) - 1;
				continue;
			}

			if (PageReserved(page))
				continue;

			page_ext = lookup_page_ext(page);
			if (unlikely(!page_ext))
				continue;

			/* Maybe overraping zone */
			if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
				continue;

			/* Found early allocated page */
			set_page_owner(page, 0, 0);
			count++;
		}
	}

	pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
		pgdat->node_id, zone->name, count);
}

static void init_zones_in_node(pg_data_t *pgdat)
{
	struct zone *zone;
	struct zone *node_zones = pgdat->node_zones;
	unsigned long flags;

	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
		if (!populated_zone(zone))
			continue;

		spin_lock_irqsave(&zone->lock, flags);
		init_pages_in_zone(pgdat, zone);
		spin_unlock_irqrestore(&zone->lock, flags);
	}
}

static void init_early_allocated_pages(void)
{
	pg_data_t *pgdat;

	drain_all_pages(NULL);
	for_each_online_pgdat(pgdat)
		init_zones_in_node(pgdat);
}

static const struct file_operations proc_page_owner_operations = {
	.read		= read_page_owner,
};

static int __init pageowner_init(void)
{
	struct dentry *dentry;

	if (!static_branch_unlikely(&page_owner_inited)) {
		pr_info("page_owner is disabled\n");
		return 0;
	}

	dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
			NULL, &proc_page_owner_operations);
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);

	return 0;
}
late_initcall(pageowner_init)
Commit	Line	Data
48c96a36 JK	1	#include <linux/debugfs.h>
	2	#include <linux/mm.h>
	3	#include <linux/slab.h>
	4	#include <linux/uaccess.h>
	5	#include <linux/bootmem.h>
	6	#include <linux/stacktrace.h>
	7	#include <linux/page_owner.h>
7dd80b8a	8	#include <linux/jump_label.h>
7cd12b4a	9	#include <linux/migrate.h>
f2ca0b55	10	#include <linux/stackdepot.h>
e2f612e6	11	#include <linux/seq_file.h>
f2ca0b55	12
48c96a36 JK	13	#include "internal.h"
48c96a36 JK	14
f2ca0b55 JK	15	/*
	16	* TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
	17	* to use off stack temporal storage
	18	*/
	19	#define PAGE_OWNER_STACK_DEPTH (16)
	20
9300d8df JK	21	struct page_owner {
	22	unsigned int order;
	23	gfp_t gfp_mask;
	24	int last_migrate_reason;
	25	depot_stack_handle_t handle;
	26	};
	27
48c96a36	28	static bool page_owner_disabled = true;
7dd80b8a	29	DEFINE_STATIC_KEY_FALSE(page_owner_inited);
48c96a36	30
f2ca0b55 JK	31	static depot_stack_handle_t dummy_handle;
	32	static depot_stack_handle_t failure_handle;
	33
61cf5feb JK	34	static void init_early_allocated_pages(void);
61cf5feb JK	35
48c96a36 JK	36	static int early_page_owner_param(char *buf)
	37	{
	38	if (!buf)
	39	return -EINVAL;
	40
	41	if (strcmp(buf, "on") == 0)
	42	page_owner_disabled = false;
	43
	44	return 0;
	45	}
	46	early_param("page_owner", early_page_owner_param);
	47
	48	static bool need_page_owner(void)
	49	{
	50	if (page_owner_disabled)
	51	return false;
	52
	53	return true;
	54	}
	55
f2ca0b55 JK	56	static noinline void register_dummy_stack(void)
	57	{
	58	unsigned long entries[4];
	59	struct stack_trace dummy;
	60
	61	dummy.nr_entries = 0;
	62	dummy.max_entries = ARRAY_SIZE(entries);
	63	dummy.entries = &entries[0];
	64	dummy.skip = 0;
	65
	66	save_stack_trace(&dummy);
	67	dummy_handle = depot_save_stack(&dummy, GFP_KERNEL);
	68	}
	69
	70	static noinline void register_failure_stack(void)
	71	{
	72	unsigned long entries[4];
	73	struct stack_trace failure;
	74
	75	failure.nr_entries = 0;
	76	failure.max_entries = ARRAY_SIZE(entries);
	77	failure.entries = &entries[0];
	78	failure.skip = 0;
	79
	80	save_stack_trace(&failure);
	81	failure_handle = depot_save_stack(&failure, GFP_KERNEL);
	82	}
	83
48c96a36 JK	84	static void init_page_owner(void)
	85	{
	86	if (page_owner_disabled)
	87	return;
	88
f2ca0b55 JK	89	register_dummy_stack();
f2ca0b55 JK	90	register_failure_stack();
7dd80b8a	91	static_branch_enable(&page_owner_inited);
61cf5feb	92	init_early_allocated_pages();
48c96a36 JK	93	}
	94
	95	struct page_ext_operations page_owner_ops = {
9300d8df	96	.size = sizeof(struct page_owner),
48c96a36 JK	97	.need = need_page_owner,
	98	.init = init_page_owner,
	99	};
	100
9300d8df JK	101	static inline struct page_owner get_page_owner(struct page_ext page_ext)
	102	{
	103	return (void *)page_ext + page_owner_ops.offset;
	104	}
	105
48c96a36 JK	106	void __reset_page_owner(struct page *page, unsigned int order)
	107	{
	108	int i;
	109	struct page_ext *page_ext;
	110
	111	for (i = 0; i < (1 << order); i++) {
	112	page_ext = lookup_page_ext(page + i);
f86e4271 YS	113	if (unlikely(!page_ext))
f86e4271 YS	114	continue;
48c96a36 JK	115	__clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
	116	}
	117	}
	118
f2ca0b55 JK	119	static inline bool check_recursive_alloc(struct stack_trace *trace,
f2ca0b55 JK	120	unsigned long ip)
48c96a36	121	{
f2ca0b55 JK	122	int i, count;
	123
	124	if (!trace->nr_entries)
	125	return false;
	126
	127	for (i = 0, count = 0; i < trace->nr_entries; i++) {
	128	if (trace->entries[i] == ip && ++count == 2)
	129	return true;
	130	}
f86e4271	131
f2ca0b55 JK	132	return false;
	133	}
	134
	135	static noinline depot_stack_handle_t save_stack(gfp_t flags)
	136	{
	137	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
94f759d6 SR	138	struct stack_trace trace = {
94f759d6 SR	139	.nr_entries = 0,
f2ca0b55 JK	140	.entries = entries,
	141	.max_entries = PAGE_OWNER_STACK_DEPTH,
	142	.skip = 0
94f759d6	143	};
f2ca0b55 JK	144	depot_stack_handle_t handle;
	145
	146	save_stack_trace(&trace);
	147	if (trace.nr_entries != 0 &&
	148	trace.entries[trace.nr_entries-1] == ULONG_MAX)
	149	trace.nr_entries--;
	150
	151	/*
	152	* We need to check recursion here because our request to stackdepot
	153	* could trigger memory allocation to save new entry. New memory
	154	* allocation would reach here and call depot_save_stack() again
	155	* if we don't catch it. There is still not enough memory in stackdepot
	156	* so it would try to allocate memory again and loop forever.
	157	*/
	158	if (check_recursive_alloc(&trace, _RET_IP_))
	159	return dummy_handle;
	160
	161	handle = depot_save_stack(&trace, flags);
	162	if (!handle)
	163	handle = failure_handle;
	164
	165	return handle;
	166	}
	167
	168	noinline void __set_page_owner(struct page *page, unsigned int order,
	169	gfp_t gfp_mask)
	170	{
	171	struct page_ext *page_ext = lookup_page_ext(page);
9300d8df	172	struct page_owner *page_owner;
48c96a36	173
f86e4271 YS	174	if (unlikely(!page_ext))
	175	return;
	176
9300d8df JK	177	page_owner = get_page_owner(page_ext);
	178	page_owner->handle = save_stack(gfp_mask);
	179	page_owner->order = order;
	180	page_owner->gfp_mask = gfp_mask;
	181	page_owner->last_migrate_reason = -1;
48c96a36 JK	182
	183	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
	184	}
	185
7cd12b4a VB	186	void __set_page_owner_migrate_reason(struct page *page, int reason)
	187	{
	188	struct page_ext *page_ext = lookup_page_ext(page);
9300d8df JK	189	struct page_owner *page_owner;
9300d8df JK	190
f86e4271 YS	191	if (unlikely(!page_ext))
f86e4271 YS	192	return;
7cd12b4a	193
9300d8df JK	194	page_owner = get_page_owner(page_ext);
9300d8df JK	195	page_owner->last_migrate_reason = reason;
7cd12b4a VB	196	}
7cd12b4a VB	197
a9627bc5	198	void __split_page_owner(struct page *page, unsigned int order)
e2cfc911	199	{
a9627bc5	200	int i;
e2cfc911	201	struct page_ext *page_ext = lookup_page_ext(page);
9300d8df	202	struct page_owner *page_owner;
a9627bc5	203
f86e4271	204	if (unlikely(!page_ext))
a9627bc5	205	return;
e2cfc911	206
9300d8df JK	207	page_owner = get_page_owner(page_ext);
9300d8df JK	208	page_owner->order = 0;
a9627bc5 JK	209	for (i = 1; i < (1 << order); i++)
a9627bc5 JK	210	__copy_page_owner(page, page + i);
e2cfc911 JK	211	}
e2cfc911 JK	212
d435edca VB	213	void __copy_page_owner(struct page oldpage, struct page newpage)
	214	{
	215	struct page_ext *old_ext = lookup_page_ext(oldpage);
	216	struct page_ext *new_ext = lookup_page_ext(newpage);
9300d8df	217	struct page_owner old_page_owner, new_page_owner;
d435edca	218
f86e4271 YS	219	if (unlikely(!old_ext \|\| !new_ext))
	220	return;
	221
9300d8df JK	222	old_page_owner = get_page_owner(old_ext);
	223	new_page_owner = get_page_owner(new_ext);
	224	new_page_owner->order = old_page_owner->order;
	225	new_page_owner->gfp_mask = old_page_owner->gfp_mask;
	226	new_page_owner->last_migrate_reason =
	227	old_page_owner->last_migrate_reason;
	228	new_page_owner->handle = old_page_owner->handle;
d435edca VB	229
	230	/*
	231	* We don't clear the bit on the oldpage as it's going to be freed
	232	* after migration. Until then, the info can be useful in case of
	233	* a bug, and the overal stats will be off a bit only temporarily.
	234	* Also, migrate_misplaced_transhuge_page() can still fail the
	235	* migration and then we want the oldpage to retain the info. But
	236	* in that case we also don't need to explicitly clear the info from
	237	* the new page, which will be freed.
	238	*/
	239	__set_bit(PAGE_EXT_OWNER, &new_ext->flags);
	240	}
	241
e2f612e6 JK	242	void pagetypeinfo_showmixedcount_print(struct seq_file *m,
	243	pg_data_t pgdat, struct zone zone)
	244	{
	245	struct page *page;
	246	struct page_ext *page_ext;
9300d8df	247	struct page_owner *page_owner;
e2f612e6 JK	248	unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
	249	unsigned long end_pfn = pfn + zone->spanned_pages;
	250	unsigned long count[MIGRATE_TYPES] = { 0, };
	251	int pageblock_mt, page_mt;
	252	int i;
	253
	254	/* Scan block by block. First and last block may be incomplete */
	255	pfn = zone->zone_start_pfn;
	256
	257	/*
	258	* Walk the zone in pageblock_nr_pages steps. If a page block spans
	259	* a zone boundary, it will be double counted between zones. This does
	260	* not matter as the mixed block count will still be correct
	261	*/
	262	for (; pfn < end_pfn; ) {
	263	if (!pfn_valid(pfn)) {
	264	pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
	265	continue;
	266	}
	267
	268	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
	269	block_end_pfn = min(block_end_pfn, end_pfn);
	270
	271	page = pfn_to_page(pfn);
	272	pageblock_mt = get_pageblock_migratetype(page);
	273
	274	for (; pfn < block_end_pfn; pfn++) {
	275	if (!pfn_valid_within(pfn))
	276	continue;
	277
	278	page = pfn_to_page(pfn);
	279
	280	if (page_zone(page) != zone)
	281	continue;
	282
	283	if (PageBuddy(page)) {
	284	pfn += (1UL << page_order(page)) - 1;
	285	continue;
	286	}
	287
	288	if (PageReserved(page))
	289	continue;
	290
	291	page_ext = lookup_page_ext(page);
	292	if (unlikely(!page_ext))
	293	continue;
	294
	295	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
	296	continue;
	297
9300d8df JK	298	page_owner = get_page_owner(page_ext);
	299	page_mt = gfpflags_to_migratetype(
	300	page_owner->gfp_mask);
e2f612e6 JK	301	if (pageblock_mt != page_mt) {
	302	if (is_migrate_cma(pageblock_mt))
	303	count[MIGRATE_MOVABLE]++;
	304	else
	305	count[pageblock_mt]++;
	306
	307	pfn = block_end_pfn;
	308	break;
	309	}
9300d8df	310	pfn += (1UL << page_owner->order) - 1;
e2f612e6 JK	311	}
	312	}
	313
	314	/* Print counts */
	315	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
	316	for (i = 0; i < MIGRATE_TYPES; i++)
	317	seq_printf(m, "%12lu ", count[i]);
	318	seq_putc(m, '\n');
	319	}
	320
48c96a36 JK	321	static ssize_t
48c96a36 JK	322	print_page_owner(char __user *buf, size_t count, unsigned long pfn,
9300d8df	323	struct page page, struct page_owner page_owner,
f2ca0b55	324	depot_stack_handle_t handle)
48c96a36 JK	325	{
	326	int ret;
	327	int pageblock_mt, page_mt;
	328	char *kbuf;
f2ca0b55	329	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
94f759d6	330	struct stack_trace trace = {
f2ca0b55 JK	331	.nr_entries = 0,
	332	.entries = entries,
	333	.max_entries = PAGE_OWNER_STACK_DEPTH,
	334	.skip = 0
94f759d6	335	};
48c96a36 JK	336
	337	kbuf = kmalloc(count, GFP_KERNEL);
	338	if (!kbuf)
	339	return -ENOMEM;
	340
	341	ret = snprintf(kbuf, count,
60f30350	342	"Page allocated via order %u, mask %#x(%pGg)\n",
9300d8df JK	343	page_owner->order, page_owner->gfp_mask,
9300d8df JK	344	&page_owner->gfp_mask);
48c96a36 JK	345
	346	if (ret >= count)
	347	goto err;
	348
	349	/* Print information relevant to grouping pages by mobility */
0b423ca2	350	pageblock_mt = get_pageblock_migratetype(page);
9300d8df	351	page_mt = gfpflags_to_migratetype(page_owner->gfp_mask);
48c96a36	352	ret += snprintf(kbuf + ret, count - ret,
60f30350	353	"PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
48c96a36	354	pfn,
60f30350	355	migratetype_names[page_mt],
48c96a36	356	pfn >> pageblock_order,
60f30350 VB	357	migratetype_names[pageblock_mt],
60f30350 VB	358	page->flags, &page->flags);
48c96a36 JK	359
	360	if (ret >= count)
	361	goto err;
	362
f2ca0b55	363	depot_fetch_stack(handle, &trace);
94f759d6	364	ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
48c96a36 JK	365	if (ret >= count)
	366	goto err;
	367
9300d8df	368	if (page_owner->last_migrate_reason != -1) {
7cd12b4a VB	369	ret += snprintf(kbuf + ret, count - ret,
7cd12b4a VB	370	"Page has been migrated, last migrate reason: %s\n",
9300d8df	371	migrate_reason_names[page_owner->last_migrate_reason]);
7cd12b4a VB	372	if (ret >= count)
	373	goto err;
	374	}
	375
48c96a36 JK	376	ret += snprintf(kbuf + ret, count - ret, "\n");
	377	if (ret >= count)
	378	goto err;
	379
	380	if (copy_to_user(buf, kbuf, ret))
	381	ret = -EFAULT;
	382
	383	kfree(kbuf);
	384	return ret;
	385
	386	err:
	387	kfree(kbuf);
	388	return -ENOMEM;
	389	}
	390
4e462112 VB	391	void __dump_page_owner(struct page *page)
	392	{
	393	struct page_ext *page_ext = lookup_page_ext(page);
9300d8df	394	struct page_owner *page_owner;
f2ca0b55	395	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
4e462112	396	struct stack_trace trace = {
f2ca0b55 JK	397	.nr_entries = 0,
	398	.entries = entries,
	399	.max_entries = PAGE_OWNER_STACK_DEPTH,
	400	.skip = 0
4e462112	401	};
f2ca0b55	402	depot_stack_handle_t handle;
8285027f SM	403	gfp_t gfp_mask;
8285027f SM	404	int mt;
4e462112	405
f86e4271 YS	406	if (unlikely(!page_ext)) {
	407	pr_alert("There is not page extension available.\n");
	408	return;
	409	}
9300d8df JK	410
	411	page_owner = get_page_owner(page_ext);
	412	gfp_mask = page_owner->gfp_mask;
8285027f	413	mt = gfpflags_to_migratetype(gfp_mask);
f86e4271	414
4e462112 VB	415	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
	416	pr_alert("page_owner info is not active (free page?)\n");
	417	return;
	418	}
	419
9300d8df	420	handle = READ_ONCE(page_owner->handle);
f2ca0b55 JK	421	if (!handle) {
	422	pr_alert("page_owner info is not active (free page?)\n");
	423	return;
	424	}
	425
	426	depot_fetch_stack(handle, &trace);
756a025f	427	pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
9300d8df	428	page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
4e462112 VB	429	print_stack_trace(&trace, 0);
4e462112 VB	430
9300d8df	431	if (page_owner->last_migrate_reason != -1)
4e462112	432	pr_alert("page has been migrated, last migrate reason: %s\n",
9300d8df	433	migrate_reason_names[page_owner->last_migrate_reason]);
4e462112 VB	434	}
4e462112 VB	435
48c96a36 JK	436	static ssize_t
	437	read_page_owner(struct file file, char __user buf, size_t count, loff_t *ppos)
	438	{
	439	unsigned long pfn;
	440	struct page *page;
	441	struct page_ext *page_ext;
9300d8df	442	struct page_owner *page_owner;
f2ca0b55	443	depot_stack_handle_t handle;
48c96a36	444
7dd80b8a	445	if (!static_branch_unlikely(&page_owner_inited))
48c96a36 JK	446	return -EINVAL;
	447
	448	page = NULL;
	449	pfn = min_low_pfn + *ppos;
	450
	451	/* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
	452	while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
	453	pfn++;
	454
	455	drain_all_pages(NULL);
	456
	457	/* Find an allocated page */
	458	for (; pfn < max_pfn; pfn++) {
	459	/*
	460	* If the new page is in a new MAX_ORDER_NR_PAGES area,
	461	* validate the area as existing, skip it if not
	462	*/
	463	if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
	464	pfn += MAX_ORDER_NR_PAGES - 1;
	465	continue;
	466	}
	467
	468	/* Check for holes within a MAX_ORDER area */
	469	if (!pfn_valid_within(pfn))
	470	continue;
	471
	472	page = pfn_to_page(pfn);
	473	if (PageBuddy(page)) {
	474	unsigned long freepage_order = page_order_unsafe(page);
	475
	476	if (freepage_order < MAX_ORDER)
	477	pfn += (1UL << freepage_order) - 1;
	478	continue;
	479	}
	480
	481	page_ext = lookup_page_ext(page);
f86e4271 YS	482	if (unlikely(!page_ext))
f86e4271 YS	483	continue;
48c96a36 JK	484
48c96a36 JK	485	/*
61cf5feb JK	486	* Some pages could be missed by concurrent allocation or free,
61cf5feb JK	487	* because we don't hold the zone lock.
48c96a36 JK	488	*/
	489	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
	490	continue;
	491
9300d8df JK	492	page_owner = get_page_owner(page_ext);
9300d8df JK	493
f2ca0b55 JK	494	/*
	495	* Access to page_ext->handle isn't synchronous so we should
	496	* be careful to access it.
	497	*/
9300d8df	498	handle = READ_ONCE(page_owner->handle);
f2ca0b55 JK	499	if (!handle)
	500	continue;
	501
48c96a36 JK	502	/* Record the next PFN to read in the file offset */
	503	*ppos = (pfn - min_low_pfn) + 1;
	504
f2ca0b55	505	return print_page_owner(buf, count, pfn, page,
9300d8df	506	page_owner, handle);
48c96a36 JK	507	}
	508
	509	return 0;
	510	}
	511
61cf5feb JK	512	static void init_pages_in_zone(pg_data_t pgdat, struct zone zone)
	513	{
	514	struct page *page;
	515	struct page_ext *page_ext;
	516	unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
	517	unsigned long end_pfn = pfn + zone->spanned_pages;
	518	unsigned long count = 0;
	519
	520	/* Scan block by block. First and last block may be incomplete */
	521	pfn = zone->zone_start_pfn;
	522
	523	/*
	524	* Walk the zone in pageblock_nr_pages steps. If a page block spans
	525	* a zone boundary, it will be double counted between zones. This does
	526	* not matter as the mixed block count will still be correct
	527	*/
	528	for (; pfn < end_pfn; ) {
	529	if (!pfn_valid(pfn)) {
	530	pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
	531	continue;
	532	}
	533
	534	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
	535	block_end_pfn = min(block_end_pfn, end_pfn);
	536
	537	page = pfn_to_page(pfn);
	538
	539	for (; pfn < block_end_pfn; pfn++) {
	540	if (!pfn_valid_within(pfn))
	541	continue;
	542
	543	page = pfn_to_page(pfn);
	544
9d43f5ae JK	545	if (page_zone(page) != zone)
	546	continue;
	547
61cf5feb JK	548	/*
	549	* We are safe to check buddy flag and order, because
	550	* this is init stage and only single thread runs.
	551	*/
	552	if (PageBuddy(page)) {
	553	pfn += (1UL << page_order(page)) - 1;
	554	continue;
	555	}
	556
	557	if (PageReserved(page))
	558	continue;
	559
	560	page_ext = lookup_page_ext(page);
f86e4271 YS	561	if (unlikely(!page_ext))
f86e4271 YS	562	continue;
61cf5feb JK	563
	564	/* Maybe overraping zone */
	565	if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
	566	continue;
	567
	568	/* Found early allocated page */
	569	set_page_owner(page, 0, 0);
	570	count++;
	571	}
	572	}
	573
	574	pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
	575	pgdat->node_id, zone->name, count);
	576	}
	577
	578	static void init_zones_in_node(pg_data_t *pgdat)
	579	{
	580	struct zone *zone;
	581	struct zone *node_zones = pgdat->node_zones;
	582	unsigned long flags;
	583
	584	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
	585	if (!populated_zone(zone))
	586	continue;
	587
	588	spin_lock_irqsave(&zone->lock, flags);
	589	init_pages_in_zone(pgdat, zone);
	590	spin_unlock_irqrestore(&zone->lock, flags);
	591	}
	592	}
	593
	594	static void init_early_allocated_pages(void)
	595	{
	596	pg_data_t *pgdat;
	597
	598	drain_all_pages(NULL);
	599	for_each_online_pgdat(pgdat)
	600	init_zones_in_node(pgdat);
	601	}
	602
48c96a36 JK	603	static const struct file_operations proc_page_owner_operations = {
	604	.read = read_page_owner,
	605	};
	606
	607	static int __init pageowner_init(void)
	608	{
	609	struct dentry *dentry;
	610
7dd80b8a	611	if (!static_branch_unlikely(&page_owner_inited)) {
48c96a36 JK	612	pr_info("page_owner is disabled\n");
	613	return 0;
	614	}
	615
	616	dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
	617	NULL, &proc_page_owner_operations);
	618	if (IS_ERR(dentry))
	619	return PTR_ERR(dentry);
	620
	621	return 0;
	622	}
44c5af96	623	late_initcall(pageowner_init)