[PATCH] mm: remove PG_highmem

Remove PG_highmem, to save a page flag.  Use is_highmem() instead.  It'll
generate a little more code, but we don't use PageHigheMem() in many places.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/frv/mm/init.c

@@ -169,7 +169,6 @@ void __init mem_init(void)
 		struct page *page = &mem_map[pfn];
 
 		ClearPageReserved(page);
-		set_bit(PG_highmem, &page->flags);
 		set_page_count(page, 1);
 		__free_page(page);
 		totalram_pages++;

arch/i386/mm/init.c

@@ -269,7 +269,6 @@ void __init one_highpage_init(struct page *page, int pfn, int bad_ppro)
 {
 	if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
 		ClearPageReserved(page);
-		set_bit(PG_highmem, &page->flags);
 		set_page_count(page, 1);
 		__free_page(page);
 		totalhigh_pages++;

arch/mips/mm/init.c

@@ -232,7 +232,6 @@ void __init mem_init(void)
 #ifdef CONFIG_LIMITED_DMA
 		set_page_address(page, lowmem_page_address(page));
 #endif
-		set_bit(PG_highmem, &page->flags);
 		set_page_count(page, 1);
 		__free_page(page);
 		totalhigh_pages++;

arch/ppc/mm/init.c

@@ -469,7 +469,6 @@ void __init mem_init(void)
 			struct page *page = mem_map + pfn;
 
 			ClearPageReserved(page);
-			set_bit(PG_highmem, &page->flags);
 			set_page_count(page, 1);
 			__free_page(page);
 			totalhigh_pages++;

arch/sparc/mm/init.c

@@ -384,7 +384,6 @@ void map_high_region(unsigned long start_pfn, unsigned long end_pfn)
 		struct page *page = pfn_to_page(tmp);
 
 		ClearPageReserved(page);
-		set_bit(PG_highmem, &page->flags);
 		set_page_count(page, 1);
 		__free_page(page);
 		totalhigh_pages++;

arch/um/kernel/mem.c

@@ -53,7 +53,6 @@ static void setup_highmem(unsigned long highmem_start,
 	for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
 		page = &mem_map[highmem_pfn + i];
 		ClearPageReserved(page);
-		set_bit(PG_highmem, &page->flags);
 		set_page_count(page, 1);
 		__free_page(page);
 	}

include/linux/page-flags.h

@@ -61,21 +61,20 @@
 #define PG_active		 6
 #define PG_slab			 7	/* slab debug (Suparna wants this) */
 
-#define PG_highmem		 8
-#define PG_checked		 9	/* kill me in 2.5.<early>. */
-#define PG_arch_1		10
-#define PG_reserved		11
-
-#define PG_private		12	/* Has something at ->private */
-#define PG_writeback		13	/* Page is under writeback */
-#define PG_nosave		14	/* Used for system suspend/resume */
-#define PG_compound		15	/* Part of a compound page */
-
-#define PG_swapcache		16	/* Swap page: swp_entry_t in private */
-#define PG_mappedtodisk		17	/* Has blocks allocated on-disk */
-#define PG_reclaim		18	/* To be reclaimed asap */
-#define PG_nosave_free		19	/* Free, should not be written */
-#define PG_uncached		20	/* Page has been mapped as uncached */
+#define PG_checked		 8	/* kill me in 2.5.<early>. */
+#define PG_arch_1		 9
+#define PG_reserved		10
+#define PG_private		11	/* Has something at ->private */
+
+#define PG_writeback		12	/* Page is under writeback */
+#define PG_nosave		13	/* Used for system suspend/resume */
+#define PG_compound		14	/* Part of a compound page */
+#define PG_swapcache		15	/* Swap page: swp_entry_t in private */
+
+#define PG_mappedtodisk		16	/* Has blocks allocated on-disk */
+#define PG_reclaim		17	/* To be reclaimed asap */
+#define PG_nosave_free		18	/* Free, should not be written */
+#define PG_uncached		19	/* Page has been mapped as uncached */
 
 /*
  * Global page accounting.  One instance per CPU.  Only unsigned longs are
@@ -215,7 +214,7 @@ extern void __mod_page_state(unsigned offset, unsigned long delta);
 #define TestSetPageSlab(page)	test_and_set_bit(PG_slab, &(page)->flags)
 
 #ifdef CONFIG_HIGHMEM
-#define PageHighMem(page)	test_bit(PG_highmem, &(page)->flags)
+#define PageHighMem(page)	is_highmem(page_zone(page))
 #else
 #define PageHighMem(page)	0 /* needed to optimize away at compile time */
 #endif