1 files changed, 79 insertions, 21 deletions

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 983c3a10fa07..44ad1f00c4e1 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -5,10 +5,12 @@
 #include <linux/bootmem.h>
 #include <linux/stacktrace.h>
 #include <linux/page_owner.h>
+#include <linux/jump_label.h>
+#include <linux/migrate.h>
 #include "internal.h"
 
 static bool page_owner_disabled = true;
-bool page_owner_inited __read_mostly;
+DEFINE_STATIC_KEY_FALSE(page_owner_inited);
 
 static void init_early_allocated_pages(void);
 
@@ -37,7 +39,7 @@ static void init_page_owner(void)
 	if (page_owner_disabled)
 		return;
 
-	page_owner_inited = true;
+	static_branch_enable(&page_owner_inited);
 	init_early_allocated_pages();
 }
 
@@ -72,10 +74,18 @@ void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask)
 	page_ext->order = order;
 	page_ext->gfp_mask = gfp_mask;
 	page_ext->nr_entries = trace.nr_entries;
+	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);
+
+	page_ext->last_migrate_reason = reason;
+}
+
 gfp_t __get_page_owner_gfp(struct page *page)
 {
 	struct page_ext *page_ext = lookup_page_ext(page);
@@ -83,6 +93,31 @@ gfp_t __get_page_owner_gfp(struct page *page)
 	return page_ext->gfp_mask;
 }
 
+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);
+	int i;
+
+	new_ext->order = old_ext->order;
+	new_ext->gfp_mask = old_ext->gfp_mask;
+	new_ext->nr_entries = old_ext->nr_entries;
+
+	for (i = 0; i < ARRAY_SIZE(new_ext->trace_entries); i++)
+		new_ext->trace_entries[i] = old_ext->trace_entries[i];
+
+	/*
+	 * 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);
+}
+
 static ssize_t
 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 		struct page *page, struct page_ext *page_ext)
@@ -100,8 +135,9 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 		return -ENOMEM;
 
 	ret = snprintf(kbuf, count,
-			"Page allocated via order %u, mask 0x%x\n",
-			page_ext->order, page_ext->gfp_mask);
+			"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;
@@ -110,23 +146,12 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 	pageblock_mt = get_pfnblock_migratetype(page, pfn);
 	page_mt  = gfpflags_to_migratetype(page_ext->gfp_mask);
 	ret += snprintf(kbuf + ret, count - ret,
-			"PFN %lu Block %lu type %d %s Flags %s%s%s%s%s%s%s%s%s%s%s%s\n",
+			"PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
 			pfn,
+			migratetype_names[page_mt],
 			pfn >> pageblock_order,
-			pageblock_mt,
-			pageblock_mt != page_mt ? "Fallback" : "        ",
-			PageLocked(page)	? "K" : " ",
-			PageError(page)		? "E" : " ",
-			PageReferenced(page)	? "R" : " ",
-			PageUptodate(page)	? "U" : " ",
-			PageDirty(page)		? "D" : " ",
-			PageLRU(page)		? "L" : " ",
-			PageActive(page)	? "A" : " ",
-			PageSlab(page)		? "S" : " ",
-			PageWriteback(page)	? "W" : " ",
-			PageCompound(page)	? "C" : " ",
-			PageSwapCache(page)	? "B" : " ",
-			PageMappedToDisk(page)	? "M" : " ");
+			migratetype_names[pageblock_mt],
+			page->flags, &page->flags);
 
 	if (ret >= count)
 		goto err;
@@ -135,6 +160,14 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 	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;
@@ -150,6 +183,31 @@ err:
 	return -ENOMEM;
 }
 
+void __dump_page_owner(struct page *page)
+{
+	struct page_ext *page_ext = lookup_page_ext(page);
+	struct stack_trace trace = {
+		.nr_entries = page_ext->nr_entries,
+		.entries = &page_ext->trace_entries[0],
+	};
+	gfp_t gfp_mask = page_ext->gfp_mask;
+	int 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;
+	}
+
+	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)
 {
@@ -157,7 +215,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 	struct page *page;
 	struct page_ext *page_ext;
 
-	if (!page_owner_inited)
+	if (!static_branch_unlikely(&page_owner_inited))
 		return -EINVAL;
 
 	page = NULL;
@@ -305,7 +363,7 @@ static int __init pageowner_init(void)
 {
 	struct dentry *dentry;
 
-	if (!page_owner_inited) {
+	if (!static_branch_unlikely(&page_owner_inited)) {
 		pr_info("page_owner is disabled\n");
 		return 0;
 	}