2 files changed, 68 insertions, 1 deletions

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index ec9eeb8..b6bcc9f 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -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))
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index af7eb08..d98ec49 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -60,6 +60,9 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
 	struct siginfo si;
 	unsigned long mask;
 
+	/* mmap_sem is performance critical.... */
+	prefetchw(&mm->mmap_sem);
+
 	/*
 	 * If we're in an interrupt or have no user context, we must not take the fault..
 	 */