Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 640 insertions, 0 deletions

diff --git a/mm/page_owner.c b/mm/page_owner.c
new file mode 100644
index 000000000..63b1053f5
--- /dev/null
+++ b/mm/page_owner.c
@@ -0,0 +1,640 @@
+// SPDX-License-Identifier: GPL-2.0
+#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 short order;
+	short last_migrate_reason;
+	gfp_t gfp_mask;
+	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 depot_stack_handle_t early_handle;
+
+static void init_early_allocated_pages(void);
+
+static int __init 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 __always_inline depot_stack_handle_t create_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);
+	return depot_save_stack(&dummy, GFP_KERNEL);
+}
+
+static noinline void register_dummy_stack(void)
+{
+	dummy_handle = create_dummy_stack();
+}
+
+static noinline void register_failure_stack(void)
+{
+	failure_handle = create_dummy_stack();
+}
+
+static noinline void register_early_stack(void)
+{
+	early_handle = create_dummy_stack();
+}
+
+static void init_page_owner(void)
+{
+	if (page_owner_disabled)
+		return;
+
+	register_dummy_stack();
+	register_failure_stack();
+	register_early_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;
+
+	if (!trace->nr_entries)
+		return false;
+
+	for (i = 0; i < trace->nr_entries; i++) {
+		if (trace->entries[i] == ip)
+			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 = 2
+	};
+	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;
+}
+
+static inline void __set_page_owner_handle(struct page_ext *page_ext,
+	depot_stack_handle_t handle, unsigned int order, gfp_t gfp_mask)
+{
+	struct page_owner *page_owner;
+
+	page_owner = get_page_owner(page_ext);
+	page_owner->handle = handle;
+	page_owner->order = order;
+	page_owner->gfp_mask = gfp_mask;
+	page_owner->last_migrate_reason = -1;
+
+	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
+}
+
+noinline void __set_page_owner(struct page *page, unsigned int order,
+					gfp_t gfp_mask)
+{
+	struct page_ext *page_ext = lookup_page_ext(page);
+	depot_stack_handle_t handle;
+
+	if (unlikely(!page_ext))
+		return;
+
+	handle = save_stack(gfp_mask);
+	__set_page_owner_handle(page_ext, handle, order, gfp_mask);
+}
+
+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; ) {
+		page = pfn_to_online_page(pfn);
+		if (!page) {
+			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);
+
+		pageblock_mt = get_pageblock_migratetype(page);
+
+		for (; pfn < block_end_pfn; pfn++) {
+			if (!pfn_valid_within(pfn))
+				continue;
+
+			/* The pageblock is online, no need to recheck. */
+			page = pfn_to_page(pfn);
+
+			if (page_zone(page) != zone)
+				continue;
+
+			if (PageBuddy(page)) {
+				unsigned long freepage_order;
+
+				freepage_order = page_order_unsafe(page);
+				if (freepage_order < MAX_ORDER)
+					pfn += (1UL << freepage_order) - 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)
+{
+	unsigned long pfn = zone->zone_start_pfn;
+	unsigned long end_pfn = zone_end_pfn(zone);
+	unsigned long count = 0;
+
+	/*
+	 * 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; ) {
+		unsigned long block_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);
+
+		for (; pfn < block_end_pfn; pfn++) {
+			struct page *page;
+			struct page_ext *page_ext;
+
+			if (!pfn_valid_within(pfn))
+				continue;
+
+			page = pfn_to_page(pfn);
+
+			if (page_zone(page) != zone)
+				continue;
+
+			/*
+			 * To avoid having to grab zone->lock, be a little
+			 * careful when reading buddy page order. The only
+			 * danger is that we skip too much and potentially miss
+			 * some early allocated pages, which is better than
+			 * heavy lock contention.
+			 */
+			if (PageBuddy(page)) {
+				unsigned long order = page_order_unsafe(page);
+
+				if (order > 0 && order < MAX_ORDER)
+					pfn += (1UL << order) - 1;
+				continue;
+			}
+
+			if (PageReserved(page))
+				continue;
+
+			page_ext = lookup_page_ext(page);
+			if (unlikely(!page_ext))
+				continue;
+
+			/* Maybe overlapping zone */
+			if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
+				continue;
+
+			/* Found early allocated page */
+			__set_page_owner_handle(page_ext, early_handle, 0, 0);
+			count++;
+		}
+		cond_resched();
+	}
+
+	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;
+
+	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
+		if (!populated_zone(zone))
+			continue;
+
+		init_pages_in_zone(pgdat, zone);
+	}
+}
+
+static void init_early_allocated_pages(void)
+{
+	pg_data_t *pgdat;
+
+	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", 0400, NULL,
+				     NULL, &proc_page_owner_operations);
+
+	return PTR_ERR_OR_ZERO(dentry);
+}
+late_initcall(pageowner_init)