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Commit 708614e6 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

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: default avatarMel 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6b74ab97

mm/internal.h

+12 −0
Original line number Diff line number Diff line
@@ -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

mm/mm_init.c

+71 −0
Original line number Diff line number Diff line
@@ -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);

mm/page_alloc.c

+8 −0
Original line number Diff line number Diff line
@@ -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);