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[IA64] Make show_mem() skip holes in a pgdat 

This patch modifies ia64's show_mem() to walk the vmem_map page tables and
rapidly skip forward across regions where the page tables are missing.
This prevents the pfn_valid() check from causing numerous unnecessary
page faults.

Without this patch on a 512 node 512 cpu system where every node has four
memory holes, the show_mem() call takes 1 hour 18 minutes.  With this
patch, it takes less than 3 seconds.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Robin Holt 2006-04-13 15:34:45 -07:00 committed by Tony Luck
parent 356a5c1c6f
commit ace1d816a1
1 changed files with 65 additions and 1 deletions
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66
arch/ia64/mm/discontig.c
View File

@ -519,6 +519,68 @@ void __cpuinit *per_cpu_init(void)
}
#endif /* CONFIG_SMP */
#ifdef CONFIG_VIRTUAL_MEM_MAP
static inline int find_next_valid_pfn_for_pgdat(pg_data_t *pgdat, int i)
{
unsigned long end_address, hole_next_pfn;
unsigned long stop_address;
end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
end_address = PAGE_ALIGN(end_address);
stop_address = (unsigned long) &vmem_map[
pgdat->node_start_pfn + pgdat->node_spanned_pages];
do {
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pgd = pgd_offset_k(end_address);
if (pgd_none(*pgd)) {
end_address += PGDIR_SIZE;
continue;
}
pud = pud_offset(pgd, end_address);
if (pud_none(*pud)) {
end_address += PUD_SIZE;
continue;
}
pmd = pmd_offset(pud, end_address);
if (pmd_none(*pmd)) {
end_address += PMD_SIZE;
continue;
}
pte = pte_offset_kernel(pmd, end_address);
retry_pte:
if (pte_none(*pte)) {
end_address += PAGE_SIZE;
pte++;
if ((end_address < stop_address) &&
(end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
goto retry_pte;
continue;
}
/* Found next valid vmem_map page */
break;
} while (end_address < stop_address);
end_address = min(end_address, stop_address);
end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
hole_next_pfn = end_address / sizeof(struct page);
return hole_next_pfn - pgdat->node_start_pfn;
}
#else
static inline int find_next_valid_pfn_for_pgdat(pg_data_t *pgdat, int i)
{
return i + 1;
}
#endif
/**
* show_mem - give short summary of memory stats
*
@ -547,8 +609,10 @@ void show_mem(void)
struct page *page;
if (pfn_valid(pgdat->node_start_pfn + i))
page = pfn_to_page(pgdat->node_start_pfn + i);
else
else {
i = find_next_valid_pfn_for_pgdat(pgdat, i) - 1;
continue;
}
if (PageReserved(page))
reserved++;
else if (PageSwapCache(page))