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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>
This commit is contained in:
Mel Gorman 2008-07-23 21:26:51 -07:00 committed by Linus Torvalds
parent 6b74ab97bc
commit 708614e618
3 changed files with 91 additions and 0 deletions
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12
mm/internal.h
View File

@ -78,6 +78,10 @@ do { \
} \
} 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,
@ -85,5 +89,13 @@ static inline void mminit_dprintk(enum mminit_level level,
{
}
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

71
mm/mm_init.c
View File

@ -7,9 +7,80 @@
*/
#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)
{
get_option(&str, &mminit_loglevel);

8
mm/page_alloc.c
View File

@ -2534,6 +2534,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
}
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 @@ __meminit int init_currently_empty_zone(struct zone *zone,
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 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
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);