x86: janitor CPA statistics patch

1) Remove __meminit from update_pages_count. It is used inside
split_pages()

2) Make the code depend on PROC_FS. Doing statistics for nothing is
useless and not adding useless code is nice to the Linux tiny folks.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/pageattr.c

@@ -34,18 +34,40 @@ struct cpa_data {
 	unsigned	force_split : 1;
 };
 
+#ifdef CONFIG_PROC_FS
 static unsigned long direct_pages_count[PG_LEVEL_NUM];
 
-void __meminit update_page_count(int level, unsigned long pages)
+void update_page_count(int level, unsigned long pages)
 {
-#ifdef CONFIG_PROC_FS
 	unsigned long flags;
+
 	/* Protect against CPA */
 	spin_lock_irqsave(&pgd_lock, flags);
 	direct_pages_count[level] += pages;
 	spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
+static void split_page_count(int level)
+{
+	direct_pages_count[level]--;
+	direct_pages_count[level - 1] += PTRS_PER_PTE;
+}
+
+int arch_report_meminfo(char *page)
+{
+	int n = sprintf(page, "DirectMap4k:  %8lu\n"
+			"DirectMap2M:  %8lu\n",
+			direct_pages_count[PG_LEVEL_4K],
+			direct_pages_count[PG_LEVEL_2M]);
+#ifdef CONFIG_X86_64
+	n += sprintf(page + n, "DirectMap1G:  %8lu\n",
+		     direct_pages_count[PG_LEVEL_1G]);
 #endif
+	return n;
 }
+#else
+static inline void split_page_count(int level) { }
+#endif
 
 #ifdef CONFIG_X86_64
 
@@ -514,10 +536,8 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 		set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
 
 	if (address >= (unsigned long)__va(0) &&
-		address < (unsigned long)__va(max_pfn_mapped << PAGE_SHIFT)) {
-		direct_pages_count[level]--;
-		direct_pages_count[level - 1] += PTRS_PER_PTE;
-	}
+		address < (unsigned long)__va(max_pfn_mapped << PAGE_SHIFT))
+		split_page_count(level);
 
 	/*
 	 * Install the new, split up pagetable. Important details here:
@@ -1048,22 +1068,6 @@ bool kernel_page_present(struct page *page)
 
 #endif /* CONFIG_DEBUG_PAGEALLOC */
 
-#ifdef CONFIG_PROC_FS
-int arch_report_meminfo(char *page)
-{
-	int n;
-	n = sprintf(page, "DirectMap4k:  %8lu\n"
-			  "DirectMap2M:  %8lu\n",
-			direct_pages_count[PG_LEVEL_4K],
-			direct_pages_count[PG_LEVEL_2M]);
-#ifdef CONFIG_X86_64
-	n += sprintf(page + n, "DirectMap1G:  %8lu\n",
-			direct_pages_count[PG_LEVEL_1G]);
-#endif
-	return n;
-}
-#endif
-
 /*
  * The testcases use internal knowledge of the implementation that shouldn't
  * be exposed to the rest of the kernel. Include these directly here.

include/asm-x86/pgtable.h

@@ -372,7 +372,11 @@ enum {
 	PG_LEVEL_NUM
 };
 
-void update_page_count(int level, unsigned long pages);
+#ifdef CONFIG_PROC_FS
+extern void update_page_count(int level, unsigned long pages);
+#else
+static inline void update_page_count(int level, unsigned long pages) { }
+#endif
 
 /*
  * Helper function that returns the kernel pagetable entry controlling