mm: verify the page links and memory model

Print out information on how the page flags are being used if mminit_loglevel is MMINIT_VERIFY or higher and unconditionally performs sanity checks on the flags regardless of loglevel. When the page flags are updated with section, node and zone information, a check are made to ensure the values can be retrieved correctly. Finally we confirm that pfn_to_page and page_to_pfn are the correct inverse functions. [akpm@linux-foundation.org: fix printk warnings] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: verify the page links and memory model
Print out information on how the page flags are being used if mminit_loglevel is MMINIT_VERIFY or higher and unconditionally performs sanity checks on the flags regardless of loglevel. When the page flags are updated with section, node and zone information, a check are made to ensure the values can be retrieved correctly. Finally we confirm that pfn_to_page and page_to_pfn are the correct inverse functions. [akpm@linux-foundation.org: fix printk warnings] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mel Gorman · Linus Torvalds
1 parent 6b74ab97bc
Showing 3 changed files with 91 additions and 0 deletions Side-by-side Diff
mm/internal.h
mm/mm_init.c
mm/page_alloc.c
@@ -78,6 +78,10 @@
 	} \
 } while (0)
  
+extern void mminit_verify_pageflags_layout(void);
+extern void mminit_verify_page_links(struct page *page,
+		enum zone_type zone, unsigned long nid, unsigned long pfn);
+
 #else
  
 static inline void mminit_dprintk(enum mminit_level level,
@@ -85,6 +89,14 @@
 {
 }
  
+static inline void mminit_verify_pageflags_layout(void)
+{
+}
+
+static inline void mminit_verify_page_links(struct page *page,
+		enum zone_type zone, unsigned long nid, unsigned long pfn)
+{
+}
 #endif /* CONFIG_DEBUG_MEMORY_INIT */
 #endif
@@ -7,8 +7,79 @@
  */
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include "internal.h"
  
 int __meminitdata mminit_loglevel;
+
+void __init mminit_verify_pageflags_layout(void)
+{
+	int shift, width;
+	unsigned long or_mask, add_mask;
+
+	shift = 8 * sizeof(unsigned long);
+	width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH;
+	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
+		"Section %d Node %d Zone %d Flags %d\n",
+		SECTIONS_WIDTH,
+		NODES_WIDTH,
+		ZONES_WIDTH,
+		NR_PAGEFLAGS);
+	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts",
+		"Section %d Node %d Zone %d\n",
+#ifdef SECTIONS_SHIFT
+		SECTIONS_SHIFT,
+#else
+		0,
+#endif
+		NODES_SHIFT,
+		ZONES_SHIFT);
+	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_offsets",
+		"Section %lu Node %lu Zone %lu\n",
+		(unsigned long)SECTIONS_PGSHIFT,
+		(unsigned long)NODES_PGSHIFT,
+		(unsigned long)ZONES_PGSHIFT);
+	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_zoneid",
+		"Zone ID: %lu -> %lu\n",
+		(unsigned long)ZONEID_PGOFF,
+		(unsigned long)(ZONEID_PGOFF + ZONEID_SHIFT));
+	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_usage",
+		"location: %d -> %d unused %d -> %d flags %d -> %d\n",
+		shift, width, width, NR_PAGEFLAGS, NR_PAGEFLAGS, 0);
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
+		"Node not in page flags");
+#endif
+
+	if (SECTIONS_WIDTH) {
+		shift -= SECTIONS_WIDTH;
+		BUG_ON(shift != SECTIONS_PGSHIFT);
+	}
+	if (NODES_WIDTH) {
+		shift -= NODES_WIDTH;
+		BUG_ON(shift != NODES_PGSHIFT);
+	}
+	if (ZONES_WIDTH) {
+		shift -= ZONES_WIDTH;
+		BUG_ON(shift != ZONES_PGSHIFT);
+	}
+
+	/* Check for bitmask overlaps */
+	or_mask = (ZONES_MASK << ZONES_PGSHIFT) |
+			(NODES_MASK << NODES_PGSHIFT) |
+			(SECTIONS_MASK << SECTIONS_PGSHIFT);
+	add_mask = (ZONES_MASK << ZONES_PGSHIFT) +
+			(NODES_MASK << NODES_PGSHIFT) +
+			(SECTIONS_MASK << SECTIONS_PGSHIFT);
+	BUG_ON(or_mask != add_mask);
+}
+
+void __meminit mminit_verify_page_links(struct page *page, enum zone_type zone,
+			unsigned long nid, unsigned long pfn)
+{
+	BUG_ON(page_to_nid(page) != nid);
+	BUG_ON(page_zonenum(page) != zone);
+	BUG_ON(page_to_pfn(page) != pfn);
+}
  
 static __init int set_mminit_loglevel(char *str)
 {
@@ -2534,6 +2534,7 @@
 		}
 		page = pfn_to_page(pfn);
 		set_page_links(page, zone, nid, pfn);
+		mminit_verify_page_links(page, zone, nid, pfn);
 		init_page_count(page);
 		reset_page_mapcount(page);
 		SetPageReserved(page);
@@ -2836,6 +2837,12 @@
  
 	zone->zone_start_pfn = zone_start_pfn;
  
+	mminit_dprintk(MMINIT_TRACE, "memmap_init",
+			"Initialising map node %d zone %lu pfns %lu -> %lu\n",
+			pgdat->node_id,
+			(unsigned long)zone_idx(zone),
+			zone_start_pfn, (zone_start_pfn + size));
+
 	zone_init_free_lists(zone);
  
 	return 0;
@@ -3961,6 +3968,7 @@
 						early_node_map[i].end_pfn);
  
 	/* Initialise every node */
+	mminit_verify_pageflags_layout();
 	setup_nr_node_ids();
 	for_each_online_node(nid) {
 		pg_data_t *pgdat = NODE_DATA(nid);
...	...	@@ -78,6 +78,10 @@
78	78	} \
79	79	} while (0)
80	80
	81	+extern void mminit_verify_pageflags_layout(void);
	82	+extern void mminit_verify_page_links(struct page *page,
	83	+ enum zone_type zone, unsigned long nid, unsigned long pfn);
	84	+
81	85	#else
82	86
83	87	static inline void mminit_dprintk(enum mminit_level level,
...	...	@@ -85,6 +89,14 @@
85	89	{
86	90	}
87	91
	92	+static inline void mminit_verify_pageflags_layout(void)
	93	+{
	94	+}
	95	+
	96	+static inline void mminit_verify_page_links(struct page *page,
	97	+ enum zone_type zone, unsigned long nid, unsigned long pfn)
	98	+{
	99	+}
88	100	#endif /* CONFIG_DEBUG_MEMORY_INIT */
89	101	#endif
...	...	@@ -7,8 +7,79 @@
7	7	*/
8	8	#include <linux/kernel.h>
9	9	#include <linux/init.h>
	10	+#include "internal.h"
10	11
11	12	int __meminitdata mminit_loglevel;
	13	+
	14	+void __init mminit_verify_pageflags_layout(void)
	15	+{
	16	+ int shift, width;
	17	+ unsigned long or_mask, add_mask;
	18	+
	19	+ shift = 8 * sizeof(unsigned long);
	20	+ width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH;
	21	+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
	22	+ "Section %d Node %d Zone %d Flags %d\n",
	23	+ SECTIONS_WIDTH,
	24	+ NODES_WIDTH,
	25	+ ZONES_WIDTH,
	26	+ NR_PAGEFLAGS);
	27	+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts",
	28	+ "Section %d Node %d Zone %d\n",
	29	+#ifdef SECTIONS_SHIFT
	30	+ SECTIONS_SHIFT,
	31	+#else
	32	+ 0,
	33	+#endif
	34	+ NODES_SHIFT,
	35	+ ZONES_SHIFT);
	36	+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_offsets",
	37	+ "Section %lu Node %lu Zone %lu\n",
	38	+ (unsigned long)SECTIONS_PGSHIFT,
	39	+ (unsigned long)NODES_PGSHIFT,
	40	+ (unsigned long)ZONES_PGSHIFT);
	41	+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_zoneid",
	42	+ "Zone ID: %lu -> %lu\n",
	43	+ (unsigned long)ZONEID_PGOFF,
	44	+ (unsigned long)(ZONEID_PGOFF + ZONEID_SHIFT));
	45	+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_usage",
	46	+ "location: %d -> %d unused %d -> %d flags %d -> %d\n",
	47	+ shift, width, width, NR_PAGEFLAGS, NR_PAGEFLAGS, 0);
	48	+#ifdef NODE_NOT_IN_PAGE_FLAGS
	49	+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
	50	+ "Node not in page flags");
	51	+#endif
	52	+
	53	+ if (SECTIONS_WIDTH) {
	54	+ shift -= SECTIONS_WIDTH;
	55	+ BUG_ON(shift != SECTIONS_PGSHIFT);
	56	+ }
	57	+ if (NODES_WIDTH) {
	58	+ shift -= NODES_WIDTH;
	59	+ BUG_ON(shift != NODES_PGSHIFT);
	60	+ }
	61	+ if (ZONES_WIDTH) {
	62	+ shift -= ZONES_WIDTH;
	63	+ BUG_ON(shift != ZONES_PGSHIFT);
	64	+ }
	65	+
	66	+ /* Check for bitmask overlaps */
	67	+ or_mask = (ZONES_MASK << ZONES_PGSHIFT) \|
	68	+ (NODES_MASK << NODES_PGSHIFT) \|
	69	+ (SECTIONS_MASK << SECTIONS_PGSHIFT);
	70	+ add_mask = (ZONES_MASK << ZONES_PGSHIFT) +
	71	+ (NODES_MASK << NODES_PGSHIFT) +
	72	+ (SECTIONS_MASK << SECTIONS_PGSHIFT);
	73	+ BUG_ON(or_mask != add_mask);
	74	+}
	75	+
	76	+void __meminit mminit_verify_page_links(struct page *page, enum zone_type zone,
	77	+ unsigned long nid, unsigned long pfn)
	78	+{
	79	+ BUG_ON(page_to_nid(page) != nid);
	80	+ BUG_ON(page_zonenum(page) != zone);
	81	+ BUG_ON(page_to_pfn(page) != pfn);
	82	+}
12	83
13	84	static __init int set_mminit_loglevel(char *str)
14	85	{
...	...	@@ -2534,6 +2534,7 @@
2534	2534	}
2535	2535	page = pfn_to_page(pfn);
2536	2536	set_page_links(page, zone, nid, pfn);
	2537	+ mminit_verify_page_links(page, zone, nid, pfn);
2537	2538	init_page_count(page);
2538	2539	reset_page_mapcount(page);
2539	2540	SetPageReserved(page);
...	...	@@ -2836,6 +2837,12 @@
2836	2837
2837	2838	zone->zone_start_pfn = zone_start_pfn;
2838	2839
	2840	+ mminit_dprintk(MMINIT_TRACE, "memmap_init",
	2841	+ "Initialising map node %d zone %lu pfns %lu -> %lu\n",
	2842	+ pgdat->node_id,
	2843	+ (unsigned long)zone_idx(zone),
	2844	+ zone_start_pfn, (zone_start_pfn + size));
	2845	+
2839	2846	zone_init_free_lists(zone);
2840	2847
2841	2848	return 0;
...	...	@@ -3961,6 +3968,7 @@
3961	3968	early_node_map[i].end_pfn);
3962	3969
3963	3970	/* Initialise every node */
	3971	+ mminit_verify_pageflags_layout();
3964	3972	setup_nr_node_ids();
3965	3973	for_each_online_node(nid) {
3966	3974	pg_data_t *pgdat = NODE_DATA(nid);