From: Mel Gorman Date: Thu, 24 Jul 2008 04:26:51 +0000 (-0700) Subject: mm: verify the page links and memory model X-Git-Tag: v2.6.27-rc1~840 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=708614e6180f398cd307ea0048d48ba6fa274610;p=linux-2.6 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 Cc: Christoph Lameter Cc: Andy Whitcroft Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/internal.h b/mm/internal.h index a7ee052532..7a4a2885dc 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -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 diff --git a/mm/mm_init.c b/mm/mm_init.c index c01d8dfec8..e16990d629 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -7,9 +7,80 @@ */ #include #include +#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); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0908352ba7..acab6ad326 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -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);