x86, mm: Unifying after_bootmem for 32bit and 64bit

after_bootmem has different meaning in 32bit and 64bit.
        32bit: after bootmem is ready
        64bit: after bootmem is distroyed
Let's merget them make 32bit the same as 64bit.

for 32bit, it is mixing alloc_bootmem_pages, and alloc_low_page under
after_bootmem is set or not set.

alloc_bootmem is just wrapper for memblock for x86.

Now we have alloc_low_page() with memblock too. We can drop bootmem path
now, and only alloc_low_page only.

At the same time, we make alloc_low_page could handle real after_bootmem
for 32bit, because alloc_bootmem_pages could fallback to use slab too.

At last move after_bootmem set position for 32bit the same as 64bit.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-40-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/mm/init.c

@@ -39,7 +39,6 @@ __ref void *alloc_low_pages(unsigned int num)
 	unsigned long pfn;
 	int i;
 
-#ifdef CONFIG_X86_64
 	if (after_bootmem) {
 		unsigned int order;
 
@@ -47,7 +46,6 @@ __ref void *alloc_low_pages(unsigned int num)
 		return (void *)__get_free_pages(GFP_ATOMIC | __GFP_NOTRACK |
 						__GFP_ZERO, order);
 	}
-#endif
 
 	if ((pgt_buf_end + num) >= pgt_buf_top) {
 		unsigned long ret;

arch/x86/mm/init_32.c

@@ -73,10 +73,7 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
 
 #ifdef CONFIG_X86_PAE
 	if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
-		if (after_bootmem)
-			pmd_table = (pmd_t *)alloc_bootmem_pages(PAGE_SIZE);
-		else
-			pmd_table = (pmd_t *)alloc_low_page();
+		pmd_table = (pmd_t *)alloc_low_page();
 		paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
 		set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
 		pud = pud_offset(pgd, 0);
@@ -98,17 +95,7 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
 static pte_t * __init one_page_table_init(pmd_t *pmd)
 {
 	if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
-		pte_t *page_table = NULL;
-
-		if (after_bootmem) {
-#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
-			page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
-#endif
-			if (!page_table)
-				page_table =
-				(pte_t *)alloc_bootmem_pages(PAGE_SIZE);
-		} else
-			page_table = (pte_t *)alloc_low_page();
+		pte_t *page_table = (pte_t *)alloc_low_page();
 
 		paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
@@ -708,8 +695,6 @@ void __init setup_bootmem_allocator(void)
 	printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 		 max_pfn_mapped<<PAGE_SHIFT);
 	printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
-
-	after_bootmem = 1;
 }
 
 /*
@@ -795,6 +780,8 @@ void __init mem_init(void)
 		if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 			reservedpages++;
 
+	after_bootmem = 1;
+
 	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;