X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=mm%2Fpage_owner.c;h=dee931184788399c920646cef75e29e8fd347186;hb=649775be63c8b2e0b56ecc5bbc96d38205ec5259;hp=addcbb2ae4e4f7e8efa3bc1df75a2f77bf9a094a;hpb=f0386617dca6deaca241a01efb9a579d0d727e7f;p=linux.git

diff --git a/mm/page_owner.c b/mm/page_owner.c
index addcbb2ae4e4..dee931184788 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -24,6 +24,9 @@ struct page_owner {
 	short last_migrate_reason;
 	gfp_t gfp_mask;
 	depot_stack_handle_t handle;
+#ifdef CONFIG_DEBUG_PAGEALLOC
+	depot_stack_handle_t free_handle;
+#endif
 };
 
 static bool page_owner_disabled = true;
@@ -102,19 +105,6 @@ 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(unsigned long *entries,
 					 unsigned int nr_entries,
 					 unsigned long ip)
@@ -154,18 +144,50 @@ static noinline depot_stack_handle_t save_stack(gfp_t flags)
 	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)
+void __reset_page_owner(struct page *page, unsigned int order)
 {
+	int i;
+	struct page_ext *page_ext;
+#ifdef CONFIG_DEBUG_PAGEALLOC
+	depot_stack_handle_t handle = 0;
 	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;
+	if (debug_pagealloc_enabled())
+		handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
+#endif
 
-	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
+	for (i = 0; i < (1 << order); i++) {
+		page_ext = lookup_page_ext(page + i);
+		if (unlikely(!page_ext))
+			continue;
+		__clear_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags);
+#ifdef CONFIG_DEBUG_PAGEALLOC
+		if (debug_pagealloc_enabled()) {
+			page_owner = get_page_owner(page_ext);
+			page_owner->free_handle = handle;
+		}
+#endif
+	}
+}
+
+static inline void __set_page_owner_handle(struct page *page,
+	struct page_ext *page_ext, depot_stack_handle_t handle,
+	unsigned int order, gfp_t gfp_mask)
+{
+	struct page_owner *page_owner;
+	int i;
+
+	for (i = 0; i < (1 << order); i++) {
+		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);
+		__set_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags);
+
+		page_ext = lookup_page_ext(page + i);
+	}
 }
 
 noinline void __set_page_owner(struct page *page, unsigned int order,
@@ -178,7 +200,7 @@ noinline void __set_page_owner(struct page *page, unsigned int order,
 		return;
 
 	handle = save_stack(gfp_mask);
-	__set_page_owner_handle(page_ext, handle, order, gfp_mask);
+	__set_page_owner_handle(page, page_ext, handle, order, gfp_mask);
 }
 
 void __set_page_owner_migrate_reason(struct page *page, int reason)
@@ -204,8 +226,11 @@ void __split_page_owner(struct page *page, unsigned int order)
 
 	page_owner = get_page_owner(page_ext);
 	page_owner->order = 0;
-	for (i = 1; i < (1 << order); i++)
-		__copy_page_owner(page, page + i);
+	for (i = 1; i < (1 << order); i++) {
+		page_ext = lookup_page_ext(page + i);
+		page_owner = get_page_owner(page_ext);
+		page_owner->order = 0;
+	}
 }
 
 void __copy_page_owner(struct page *oldpage, struct page *newpage)
@@ -235,6 +260,7 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage)
 	 * the new page, which will be freed.
 	 */
 	__set_bit(PAGE_EXT_OWNER, &new_ext->flags);
+	__set_bit(PAGE_EXT_OWNER_ACTIVE, &new_ext->flags);
 }
 
 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
@@ -294,7 +320,7 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 			if (unlikely(!page_ext))
 				continue;
 
-			if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
+			if (!test_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags))
 				continue;
 
 			page_owner = get_page_owner(page_ext);
@@ -405,20 +431,36 @@ void __dump_page_owner(struct page *page)
 	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");
+		pr_alert("page_owner info is not present (never set?)\n");
 		return;
 	}
 
+	if (test_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags))
+		pr_alert("page_owner tracks the page as allocated\n");
+	else
+		pr_alert("page_owner tracks the page as freed\n");
+
+	pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
+		 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
+
 	handle = READ_ONCE(page_owner->handle);
 	if (!handle) {
-		pr_alert("page_owner info is not active (free page?)\n");
-		return;
+		pr_alert("page_owner allocation stack trace missing\n");
+	} else {
+		nr_entries = stack_depot_fetch(handle, &entries);
+		stack_trace_print(entries, nr_entries, 0);
 	}
 
-	nr_entries = stack_depot_fetch(handle, &entries);
-	pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
-		 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
-	stack_trace_print(entries, nr_entries, 0);
+#ifdef CONFIG_DEBUG_PAGEALLOC
+	handle = READ_ONCE(page_owner->free_handle);
+	if (!handle) {
+		pr_alert("page_owner free stack trace missing\n");
+	} else {
+		nr_entries = stack_depot_fetch(handle, &entries);
+		pr_alert("page last free stack trace:\n");
+		stack_trace_print(entries, nr_entries, 0);
+	}
+#endif
 
 	if (page_owner->last_migrate_reason != -1)
 		pr_alert("page has been migrated, last migrate reason: %s\n",
@@ -481,8 +523,22 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 			continue;
 
+		/*
+		 * Although we do have the info about past allocation of free
+		 * pages, it's not relevant for current memory usage.
+		 */
+		if (!test_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags))
+			continue;
+
 		page_owner = get_page_owner(page_ext);
 
+		/*
+		 * Don't print "tail" pages of high-order allocations as that
+		 * would inflate the stats.
+		 */
+		if (!IS_ALIGNED(pfn, 1 << page_owner->order))
+			continue;
+
 		/*
 		 * Access to page_ext->handle isn't synchronous so we should
 		 * be careful to access it.
@@ -562,7 +618,8 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 				continue;
 
 			/* Found early allocated page */
-			__set_page_owner_handle(page_ext, early_handle, 0, 0);
+			__set_page_owner_handle(page, page_ext, early_handle,
+						0, 0);
 			count++;
 		}
 		cond_resched();