[mirror_ubuntu-bionic-kernel.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)

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 = {
	.need = need_page_owner,
	.init = init_page_owner,
};

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);

	if (unlikely(!page_ext))
		return;

	page_ext->handle = save_stack(gfp_mask);
	page_ext->order = order;
	page_ext->gfp_mask = gfp_mask;
	page_ext->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);
	if (unlikely(!page_ext))
		return;

	page_ext->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);

	if (unlikely(!page_ext))
		return;

	page_ext->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);

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

	new_ext->order = old_ext->order;
	new_ext->gfp_mask = old_ext->gfp_mask;
	new_ext->last_migrate_reason = old_ext->last_migrate_reason;
	new_ext->handle = old_ext->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;
	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_mt = gfpflags_to_migratetype(page_ext->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_ext->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_ext *page_ext,
		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_ext->order, page_ext->gfp_mask,
			&page_ext->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_ext->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_ext->last_migrate_reason != -1) {
		ret += snprintf(kbuf + ret, count - ret,
			"Page has been migrated, last migrate reason: %s\n",
			migrate_reason_names[page_ext->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);
	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;
	}
	gfp_mask = page_ext->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_ext->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_ext->order, migratetype_names[mt], gfp_mask, &gfp_mask);
	print_stack_trace(&trace, 0);

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

		/*
		 * Access to page_ext->handle isn't synchronous so we should
		 * be careful to access it.
		 */
		handle = READ_ONCE(page_ext->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_ext, 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
48c96a36	21	static bool page_owner_disabled = true;
7dd80b8a	22	DEFINE_STATIC_KEY_FALSE(page_owner_inited);
48c96a36	23
f2ca0b55 JK	24	static depot_stack_handle_t dummy_handle;
	25	static depot_stack_handle_t failure_handle;
	26
61cf5feb JK	27	static void init_early_allocated_pages(void);
61cf5feb JK	28
48c96a36 JK	29	static int early_page_owner_param(char *buf)
	30	{
	31	if (!buf)
	32	return -EINVAL;
	33
	34	if (strcmp(buf, "on") == 0)
	35	page_owner_disabled = false;
	36
	37	return 0;
	38	}
	39	early_param("page_owner", early_page_owner_param);
	40
	41	static bool need_page_owner(void)
	42	{
	43	if (page_owner_disabled)
	44	return false;
	45
	46	return true;
	47	}
	48
f2ca0b55 JK	49	static noinline void register_dummy_stack(void)
	50	{
	51	unsigned long entries[4];
	52	struct stack_trace dummy;
	53
	54	dummy.nr_entries = 0;
	55	dummy.max_entries = ARRAY_SIZE(entries);
	56	dummy.entries = &entries[0];
	57	dummy.skip = 0;
	58
	59	save_stack_trace(&dummy);
	60	dummy_handle = depot_save_stack(&dummy, GFP_KERNEL);
	61	}
	62
	63	static noinline void register_failure_stack(void)
	64	{
	65	unsigned long entries[4];
	66	struct stack_trace failure;
	67
	68	failure.nr_entries = 0;
	69	failure.max_entries = ARRAY_SIZE(entries);
	70	failure.entries = &entries[0];
	71	failure.skip = 0;
	72
	73	save_stack_trace(&failure);
	74	failure_handle = depot_save_stack(&failure, GFP_KERNEL);
	75	}
	76
48c96a36 JK	77	static void init_page_owner(void)
	78	{
	79	if (page_owner_disabled)
	80	return;
	81
f2ca0b55 JK	82	register_dummy_stack();
f2ca0b55 JK	83	register_failure_stack();
7dd80b8a	84	static_branch_enable(&page_owner_inited);
61cf5feb	85	init_early_allocated_pages();
48c96a36 JK	86	}
	87
	88	struct page_ext_operations page_owner_ops = {
	89	.need = need_page_owner,
	90	.init = init_page_owner,
	91	};
	92
	93	void __reset_page_owner(struct page *page, unsigned int order)
	94	{
	95	int i;
	96	struct page_ext *page_ext;
	97
	98	for (i = 0; i < (1 << order); i++) {
	99	page_ext = lookup_page_ext(page + i);
f86e4271 YS	100	if (unlikely(!page_ext))
f86e4271 YS	101	continue;
48c96a36 JK	102	__clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
	103	}
	104	}
	105
f2ca0b55 JK	106	static inline bool check_recursive_alloc(struct stack_trace *trace,
f2ca0b55 JK	107	unsigned long ip)
48c96a36	108	{
f2ca0b55 JK	109	int i, count;
	110
	111	if (!trace->nr_entries)
	112	return false;
	113
	114	for (i = 0, count = 0; i < trace->nr_entries; i++) {
	115	if (trace->entries[i] == ip && ++count == 2)
	116	return true;
	117	}
f86e4271	118
f2ca0b55 JK	119	return false;
	120	}
	121
	122	static noinline depot_stack_handle_t save_stack(gfp_t flags)
	123	{
	124	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
94f759d6 SR	125	struct stack_trace trace = {
94f759d6 SR	126	.nr_entries = 0,
f2ca0b55 JK	127	.entries = entries,
	128	.max_entries = PAGE_OWNER_STACK_DEPTH,
	129	.skip = 0
94f759d6	130	};
f2ca0b55 JK	131	depot_stack_handle_t handle;
	132
	133	save_stack_trace(&trace);
	134	if (trace.nr_entries != 0 &&
	135	trace.entries[trace.nr_entries-1] == ULONG_MAX)
	136	trace.nr_entries--;
	137
	138	/*
	139	* We need to check recursion here because our request to stackdepot
	140	* could trigger memory allocation to save new entry. New memory
	141	* allocation would reach here and call depot_save_stack() again
	142	* if we don't catch it. There is still not enough memory in stackdepot
	143	* so it would try to allocate memory again and loop forever.
	144	*/
	145	if (check_recursive_alloc(&trace, _RET_IP_))
	146	return dummy_handle;
	147
	148	handle = depot_save_stack(&trace, flags);
	149	if (!handle)
	150	handle = failure_handle;
	151
	152	return handle;
	153	}
	154
	155	noinline void __set_page_owner(struct page *page, unsigned int order,
	156	gfp_t gfp_mask)
	157	{
	158	struct page_ext *page_ext = lookup_page_ext(page);
48c96a36	159
f86e4271 YS	160	if (unlikely(!page_ext))
	161	return;
	162
f2ca0b55	163	page_ext->handle = save_stack(gfp_mask);
48c96a36 JK	164	page_ext->order = order;
48c96a36 JK	165	page_ext->gfp_mask = gfp_mask;
7cd12b4a	166	page_ext->last_migrate_reason = -1;
48c96a36 JK	167
	168	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
	169	}
	170
7cd12b4a VB	171	void __set_page_owner_migrate_reason(struct page *page, int reason)
	172	{
	173	struct page_ext *page_ext = lookup_page_ext(page);
f86e4271 YS	174	if (unlikely(!page_ext))
f86e4271 YS	175	return;
7cd12b4a VB	176
	177	page_ext->last_migrate_reason = reason;
	178	}
	179
a9627bc5	180	void __split_page_owner(struct page *page, unsigned int order)
e2cfc911	181	{
a9627bc5	182	int i;
e2cfc911	183	struct page_ext *page_ext = lookup_page_ext(page);
a9627bc5	184
f86e4271	185	if (unlikely(!page_ext))
a9627bc5	186	return;
e2cfc911	187
a9627bc5 JK	188	page_ext->order = 0;
	189	for (i = 1; i < (1 << order); i++)
	190	__copy_page_owner(page, page + i);
e2cfc911 JK	191	}
e2cfc911 JK	192
d435edca VB	193	void __copy_page_owner(struct page oldpage, struct page newpage)
	194	{
	195	struct page_ext *old_ext = lookup_page_ext(oldpage);
	196	struct page_ext *new_ext = lookup_page_ext(newpage);
d435edca	197
f86e4271 YS	198	if (unlikely(!old_ext \|\| !new_ext))
	199	return;
	200
d435edca VB	201	new_ext->order = old_ext->order;
d435edca VB	202	new_ext->gfp_mask = old_ext->gfp_mask;
a8efe1c9	203	new_ext->last_migrate_reason = old_ext->last_migrate_reason;
f2ca0b55	204	new_ext->handle = old_ext->handle;
d435edca VB	205
	206	/*
	207	* We don't clear the bit on the oldpage as it's going to be freed
	208	* after migration. Until then, the info can be useful in case of
	209	* a bug, and the overal stats will be off a bit only temporarily.
	210	* Also, migrate_misplaced_transhuge_page() can still fail the
	211	* migration and then we want the oldpage to retain the info. But
	212	* in that case we also don't need to explicitly clear the info from
	213	* the new page, which will be freed.
	214	*/
	215	__set_bit(PAGE_EXT_OWNER, &new_ext->flags);
	216	}
	217
e2f612e6 JK	218	void pagetypeinfo_showmixedcount_print(struct seq_file *m,
	219	pg_data_t pgdat, struct zone zone)
	220	{
	221	struct page *page;
	222	struct page_ext *page_ext;
	223	unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
	224	unsigned long end_pfn = pfn + zone->spanned_pages;
	225	unsigned long count[MIGRATE_TYPES] = { 0, };
	226	int pageblock_mt, page_mt;
	227	int i;
	228
	229	/* Scan block by block. First and last block may be incomplete */
	230	pfn = zone->zone_start_pfn;
	231
	232	/*
	233	* Walk the zone in pageblock_nr_pages steps. If a page block spans
	234	* a zone boundary, it will be double counted between zones. This does
	235	* not matter as the mixed block count will still be correct
	236	*/
	237	for (; pfn < end_pfn; ) {
	238	if (!pfn_valid(pfn)) {
	239	pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
	240	continue;
	241	}
	242
	243	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
	244	block_end_pfn = min(block_end_pfn, end_pfn);
	245
	246	page = pfn_to_page(pfn);
	247	pageblock_mt = get_pageblock_migratetype(page);
	248
	249	for (; pfn < block_end_pfn; pfn++) {
	250	if (!pfn_valid_within(pfn))
	251	continue;
	252
	253	page = pfn_to_page(pfn);
	254
	255	if (page_zone(page) != zone)
	256	continue;
	257
	258	if (PageBuddy(page)) {
	259	pfn += (1UL << page_order(page)) - 1;
	260	continue;
	261	}
	262
	263	if (PageReserved(page))
	264	continue;
	265
	266	page_ext = lookup_page_ext(page);
	267	if (unlikely(!page_ext))
	268	continue;
	269
	270	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
	271	continue;
	272
	273	page_mt = gfpflags_to_migratetype(page_ext->gfp_mask);
	274	if (pageblock_mt != page_mt) {
	275	if (is_migrate_cma(pageblock_mt))
	276	count[MIGRATE_MOVABLE]++;
	277	else
	278	count[pageblock_mt]++;
	279
	280	pfn = block_end_pfn;
	281	break;
282	}
283	pfn += (1UL << page_ext->order) - 1;
284	}
285	}
286
287	/* Print counts */
288	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
289	for (i = 0; i < MIGRATE_TYPES; i++)
290	seq_printf(m, "%12lu ", count[i]);
291	seq_putc(m, '\n');
292	}
293
48c96a36 JK	294	static ssize_t
48c96a36 JK	295	print_page_owner(char __user *buf, size_t count, unsigned long pfn,
f2ca0b55 JK	296	struct page page, struct page_ext page_ext,
f2ca0b55 JK	297	depot_stack_handle_t handle)
48c96a36 JK	298	{
	299	int ret;
	300	int pageblock_mt, page_mt;
	301	char *kbuf;
f2ca0b55	302	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
94f759d6	303	struct stack_trace trace = {
f2ca0b55 JK	304	.nr_entries = 0,
	305	.entries = entries,
	306	.max_entries = PAGE_OWNER_STACK_DEPTH,
	307	.skip = 0
94f759d6	308	};
48c96a36 JK	309
	310	kbuf = kmalloc(count, GFP_KERNEL);
	311	if (!kbuf)
	312	return -ENOMEM;
	313
	314	ret = snprintf(kbuf, count,
60f30350 VB	315	"Page allocated via order %u, mask %#x(%pGg)\n",
	316	page_ext->order, page_ext->gfp_mask,
	317	&page_ext->gfp_mask);
48c96a36 JK	318
	319	if (ret >= count)
	320	goto err;
	321
	322	/* Print information relevant to grouping pages by mobility */
0b423ca2	323	pageblock_mt = get_pageblock_migratetype(page);
48c96a36 JK	324	page_mt = gfpflags_to_migratetype(page_ext->gfp_mask);
48c96a36 JK	325	ret += snprintf(kbuf + ret, count - ret,
60f30350	326	"PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
48c96a36	327	pfn,
60f30350	328	migratetype_names[page_mt],
48c96a36	329	pfn >> pageblock_order,
60f30350 VB	330	migratetype_names[pageblock_mt],
60f30350 VB	331	page->flags, &page->flags);
48c96a36 JK	332
	333	if (ret >= count)
	334	goto err;
	335
f2ca0b55	336	depot_fetch_stack(handle, &trace);
94f759d6	337	ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
48c96a36 JK	338	if (ret >= count)
	339	goto err;
	340
7cd12b4a VB	341	if (page_ext->last_migrate_reason != -1) {
	342	ret += snprintf(kbuf + ret, count - ret,
	343	"Page has been migrated, last migrate reason: %s\n",
	344	migrate_reason_names[page_ext->last_migrate_reason]);
	345	if (ret >= count)
	346	goto err;
	347	}
	348
48c96a36 JK	349	ret += snprintf(kbuf + ret, count - ret, "\n");
	350	if (ret >= count)
	351	goto err;
	352
	353	if (copy_to_user(buf, kbuf, ret))
	354	ret = -EFAULT;
	355
	356	kfree(kbuf);
	357	return ret;
	358
	359	err:
	360	kfree(kbuf);
	361	return -ENOMEM;
	362	}
	363
4e462112 VB	364	void __dump_page_owner(struct page *page)
	365	{
	366	struct page_ext *page_ext = lookup_page_ext(page);
f2ca0b55	367	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
4e462112	368	struct stack_trace trace = {
f2ca0b55 JK	369	.nr_entries = 0,
	370	.entries = entries,
	371	.max_entries = PAGE_OWNER_STACK_DEPTH,
	372	.skip = 0
4e462112	373	};
f2ca0b55	374	depot_stack_handle_t handle;
8285027f SM	375	gfp_t gfp_mask;
8285027f SM	376	int mt;
4e462112	377
f86e4271 YS	378	if (unlikely(!page_ext)) {
	379	pr_alert("There is not page extension available.\n");
	380	return;
	381	}
8285027f SM	382	gfp_mask = page_ext->gfp_mask;
8285027f SM	383	mt = gfpflags_to_migratetype(gfp_mask);
f86e4271	384
4e462112 VB	385	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
	386	pr_alert("page_owner info is not active (free page?)\n");
	387	return;
	388	}
	389
f2ca0b55 JK	390	handle = READ_ONCE(page_ext->handle);
	391	if (!handle) {
	392	pr_alert("page_owner info is not active (free page?)\n");
	393	return;
	394	}
	395
	396	depot_fetch_stack(handle, &trace);
756a025f JP	397	pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
756a025f JP	398	page_ext->order, migratetype_names[mt], gfp_mask, &gfp_mask);
4e462112 VB	399	print_stack_trace(&trace, 0);
	400
	401	if (page_ext->last_migrate_reason != -1)
	402	pr_alert("page has been migrated, last migrate reason: %s\n",
	403	migrate_reason_names[page_ext->last_migrate_reason]);
	404	}
	405
48c96a36 JK	406	static ssize_t
	407	read_page_owner(struct file file, char __user buf, size_t count, loff_t *ppos)
	408	{
	409	unsigned long pfn;
	410	struct page *page;
	411	struct page_ext *page_ext;
f2ca0b55	412	depot_stack_handle_t handle;
48c96a36	413
7dd80b8a	414	if (!static_branch_unlikely(&page_owner_inited))
48c96a36 JK	415	return -EINVAL;
	416
	417	page = NULL;
	418	pfn = min_low_pfn + *ppos;
	419
	420	/* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
	421	while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
	422	pfn++;
	423
	424	drain_all_pages(NULL);
	425
	426	/* Find an allocated page */
	427	for (; pfn < max_pfn; pfn++) {
	428	/*
	429	* If the new page is in a new MAX_ORDER_NR_PAGES area,
	430	* validate the area as existing, skip it if not
	431	*/
	432	if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
	433	pfn += MAX_ORDER_NR_PAGES - 1;
	434	continue;
	435	}
	436
	437	/* Check for holes within a MAX_ORDER area */
	438	if (!pfn_valid_within(pfn))
	439	continue;
	440
	441	page = pfn_to_page(pfn);
	442	if (PageBuddy(page)) {
	443	unsigned long freepage_order = page_order_unsafe(page);
	444
	445	if (freepage_order < MAX_ORDER)
	446	pfn += (1UL << freepage_order) - 1;
	447	continue;
	448	}
	449
	450	page_ext = lookup_page_ext(page);
f86e4271 YS	451	if (unlikely(!page_ext))
f86e4271 YS	452	continue;
48c96a36 JK	453
48c96a36 JK	454	/*
61cf5feb JK	455	* Some pages could be missed by concurrent allocation or free,
61cf5feb JK	456	* because we don't hold the zone lock.
48c96a36 JK	457	*/
	458	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
	459	continue;
	460
f2ca0b55 JK	461	/*
	462	* Access to page_ext->handle isn't synchronous so we should
	463	* be careful to access it.
	464	*/
	465	handle = READ_ONCE(page_ext->handle);
	466	if (!handle)
	467	continue;
	468
48c96a36 JK	469	/* Record the next PFN to read in the file offset */
	470	*ppos = (pfn - min_low_pfn) + 1;
	471
f2ca0b55 JK	472	return print_page_owner(buf, count, pfn, page,
f2ca0b55 JK	473	page_ext, handle);
48c96a36 JK	474	}
	475
	476	return 0;
	477	}
	478
61cf5feb JK	479	static void init_pages_in_zone(pg_data_t pgdat, struct zone zone)
	480	{
	481	struct page *page;
	482	struct page_ext *page_ext;
	483	unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
	484	unsigned long end_pfn = pfn + zone->spanned_pages;
	485	unsigned long count = 0;
	486
	487	/* Scan block by block. First and last block may be incomplete */
	488	pfn = zone->zone_start_pfn;
	489
	490	/*
	491	* Walk the zone in pageblock_nr_pages steps. If a page block spans
	492	* a zone boundary, it will be double counted between zones. This does
	493	* not matter as the mixed block count will still be correct
	494	*/
	495	for (; pfn < end_pfn; ) {
	496	if (!pfn_valid(pfn)) {
	497	pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
	498	continue;
	499	}
	500
	501	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
	502	block_end_pfn = min(block_end_pfn, end_pfn);
	503
	504	page = pfn_to_page(pfn);
	505
	506	for (; pfn < block_end_pfn; pfn++) {
	507	if (!pfn_valid_within(pfn))
	508	continue;
	509
	510	page = pfn_to_page(pfn);
	511
9d43f5ae JK	512	if (page_zone(page) != zone)
	513	continue;
	514
61cf5feb JK	515	/*
	516	* We are safe to check buddy flag and order, because
	517	* this is init stage and only single thread runs.
	518	*/
	519	if (PageBuddy(page)) {
	520	pfn += (1UL << page_order(page)) - 1;
	521	continue;
	522	}
	523
	524	if (PageReserved(page))
	525	continue;
	526
	527	page_ext = lookup_page_ext(page);
f86e4271 YS	528	if (unlikely(!page_ext))
f86e4271 YS	529	continue;
61cf5feb JK	530
	531	/* Maybe overraping zone */
	532	if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
	533	continue;
	534
	535	/* Found early allocated page */
	536	set_page_owner(page, 0, 0);
	537	count++;
	538	}
	539	}
	540
	541	pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
	542	pgdat->node_id, zone->name, count);
	543	}
	544
	545	static void init_zones_in_node(pg_data_t *pgdat)
	546	{
	547	struct zone *zone;
	548	struct zone *node_zones = pgdat->node_zones;
	549	unsigned long flags;
	550
	551	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
	552	if (!populated_zone(zone))
	553	continue;
	554
	555	spin_lock_irqsave(&zone->lock, flags);
	556	init_pages_in_zone(pgdat, zone);
	557	spin_unlock_irqrestore(&zone->lock, flags);
	558	}
	559	}
	560
	561	static void init_early_allocated_pages(void)
	562	{
	563	pg_data_t *pgdat;
	564
	565	drain_all_pages(NULL);
	566	for_each_online_pgdat(pgdat)
	567	init_zones_in_node(pgdat);
	568	}
	569
48c96a36 JK	570	static const struct file_operations proc_page_owner_operations = {
	571	.read = read_page_owner,
	572	};
	573
	574	static int __init pageowner_init(void)
	575	{
	576	struct dentry *dentry;
	577
7dd80b8a	578	if (!static_branch_unlikely(&page_owner_inited)) {
48c96a36 JK	579	pr_info("page_owner is disabled\n");
	580	return 0;
	581	}
	582
	583	dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
	584	NULL, &proc_page_owner_operations);
	585	if (IS_ERR(dentry))
	586	return PTR_ERR(dentry);
	587
	588	return 0;
	589	}
44c5af96	590	late_initcall(pageowner_init)