[PATCH] remove non-DISCONTIG use of pgdat->node_mem_map

This patch effectively eliminates direct use of pgdat->node_mem_map outside
of the DISCONTIG code.  On a flat memory system, these fields aren't
currently used, neither are they on a sparsemem system.

There was also a node_mem_map(nid) macro on many architectures.  Its use
along with the use of ->node_mem_map itself was not consistent.  It has
been removed in favor of two new, more explicit, arch-independent macros:

	pgdat_page_nr(pgdat, pagenr)
	nid_page_nr(nid, pagenr)

I called them "pgdat" and "nid" because we overload the term "node" to mean
"NUMA node", "DISCONTIG node" or "pg_data_t" in very confusing ways.  I
believe the newer names are much clearer.

These macros can be overridden in the sparsemem case with a theoretically
slower operation using node_start_pfn and pfn_to_page(), instead.  We could
make this the only behavior if people want, but I don't want to change too
much at once.  One thing at a time.

This patch removes more code than it adds.

Compile tested on alpha, alpha discontig, arm, arm-discontig, i386, i386
generic, NUMAQ, Summit, ppc64, ppc64 discontig, and x86_64.  Full list
here: http://sr71.net/patches/2.6.12/2.6.12-rc1-mhp2/configs/

Boot tested on NUMAQ, x86 SMP and ppc64 power4/5 LPARs.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin J. Bligh <mbligh@aracnet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

7 files changed, 20 insertions, 22 deletions

diff --git a/arch/alpha/mm/numa.c b/arch/alpha/mm/numa.c
index ba81c4422aa..c7481d59b6d 100644
--- a/arch/alpha/mm/numa.c
+++ b/arch/alpha/mm/numa.c
@@ -327,8 +327,6 @@ void __init mem_init(void)
 	extern char _text, _etext, _data, _edata;
 	extern char __init_begin, __init_end;
 	unsigned long nid, i;
-	struct page * lmem_map;
-
 	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
 
 	reservedpages = 0;
@@ -338,10 +336,10 @@ void __init mem_init(void)
 		 */
 		totalram_pages += free_all_bootmem_node(NODE_DATA(nid));
 
-		lmem_map = node_mem_map(nid);
 		pfn = NODE_DATA(nid)->node_start_pfn;
 		for (i = 0; i < node_spanned_pages(nid); i++, pfn++)
-			if (page_is_ram(pfn) && PageReserved(lmem_map+i))
+			if (page_is_ram(pfn) &&
+			    PageReserved(nid_page_nr(nid, i)))
 				reservedpages++;
 	}
 
@@ -373,18 +371,18 @@ show_mem(void)
 	show_free_areas();
 	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 	for_each_online_node(nid) {
-		struct page * lmem_map = node_mem_map(nid);
 		i = node_spanned_pages(nid);
 		while (i-- > 0) {
+			struct page *page = nid_page_nr(nid, i);
 			total++;
-			if (PageReserved(lmem_map+i))
+			if (PageReserved(page))
 				reserved++;
-			else if (PageSwapCache(lmem_map+i))
+			else if (PageSwapCache(page))
 				cached++;
-			else if (!page_count(lmem_map+i))
+			else if (!page_count(page))
 				free++;
 			else
-				shared += page_count(lmem_map + i) - 1;
+				shared += page_count(page) - 1;
 		}
 	}
 	printk("%ld pages of RAM\n",total);
diff --git a/arch/i386/mm/pgtable.c b/arch/i386/mm/pgtable.c
index dd81479ff88..80c84cdf22e 100644
--- a/arch/i386/mm/pgtable.c
+++ b/arch/i386/mm/pgtable.c
@@ -36,7 +36,7 @@ void show_mem(void)
 	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 	for_each_pgdat(pgdat) {
 		for (i = 0; i < pgdat->node_spanned_pages; ++i) {
-			page = pgdat->node_mem_map + i;
+			page = pgdat_page_nr(pgdat, i);
 			total++;
 			if (PageHighMem(page))
 				highmem++;
diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index c0071092939..f3fd528ead3 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -560,14 +560,15 @@ void show_mem(void)
 		int shared = 0, cached = 0, reserved = 0;
 		printk("Node ID: %d\n", pgdat->node_id);
 		for(i = 0; i < pgdat->node_spanned_pages; i++) {
+			struct page *page = pgdat_page_nr(pgdat, i);
 			if (!ia64_pfn_valid(pgdat->node_start_pfn+i))
 				continue;
-			if (PageReserved(pgdat->node_mem_map+i))
+			if (PageReserved(page))
 				reserved++;
-			else if (PageSwapCache(pgdat->node_mem_map+i))
+			else if (PageSwapCache(page))
 				cached++;
-			else if (page_count(pgdat->node_mem_map+i))
-				shared += page_count(pgdat->node_mem_map+i)-1;
+			else if (page_count(page))
+				shared += page_count(page)-1;
 		}
 		total_present += present;
 		total_reserved += reserved;
diff --git a/arch/m32r/mm/init.c b/arch/m32r/mm/init.c
index bc423d838fb..d9a40b1fe8b 100644
--- a/arch/m32r/mm/init.c
+++ b/arch/m32r/mm/init.c
@@ -49,7 +49,7 @@ void show_mem(void)
 	printk("Free swap:       %6ldkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
 	for_each_pgdat(pgdat) {
 		for (i = 0; i < pgdat->node_spanned_pages; ++i) {
-			page = pgdat->node_mem_map + i;
+			page = pgdat_page_nr(pgdat, i);
 			total++;
 			if (PageHighMem(page))
 				highmem++;
@@ -152,7 +152,7 @@ int __init reservedpages_count(void)
 	reservedpages = 0;
 	for_each_online_node(nid)
 		for (i = 0 ; i < MAX_LOW_PFN(nid) - START_PFN(nid) ; i++)
-			if (PageReserved(NODE_DATA(nid)->node_mem_map + i))
+			if (PageReserved(nid_page_nr(nid, i)))
 				reservedpages++;
 
 	return reservedpages;
diff --git a/arch/mips/sgi-ip27/ip27-memory.c b/arch/mips/sgi-ip27/ip27-memory.c
index 0a44a98d7ad..a160d04f7db 100644
--- a/arch/mips/sgi-ip27/ip27-memory.c
+++ b/arch/mips/sgi-ip27/ip27-memory.c
@@ -549,9 +549,8 @@ void __init mem_init(void)
 		 */
 		numslots = node_getlastslot(node);
 		for (slot = 1; slot <= numslots; slot++) {
-			p = NODE_DATA(node)->node_mem_map +
-				(slot_getbasepfn(node, slot) -
-				 slot_getbasepfn(node, 0));
+			p = nid_page_nr(node, slot_getbasepfn(node, slot) -
+					      slot_getbasepfn(node, 0));
 
 			/*
 			 * Free valid memory in current slot.
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index cac37589e35..2886ad70db4 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -506,7 +506,7 @@ void show_mem(void)
 		for (j = node_start_pfn(i); j < node_end_pfn(i); j++) {
 			struct page *p;
 
-			p = node_mem_map(i) + j - node_start_pfn(i);
+			p = nid_page_nr(i, j) - node_start_pfn(i);
 
 			total++;
 			if (PageReserved(p))
diff --git a/arch/ppc64/mm/init.c b/arch/ppc64/mm/init.c
index 6fa1e6490b5..29dbe084c21 100644
--- a/arch/ppc64/mm/init.c
+++ b/arch/ppc64/mm/init.c
@@ -98,7 +98,7 @@ void show_mem(void)
 	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 	for_each_pgdat(pgdat) {
 		for (i = 0; i < pgdat->node_spanned_pages; i++) {
-			page = pgdat->node_mem_map + i;
+			page = pgdat_page_nr(pgdat, i);
 			total++;
 			if (PageReserved(page))
 				reserved++;
@@ -654,7 +654,7 @@ void __init mem_init(void)
 
 	for_each_pgdat(pgdat) {
 		for (i = 0; i < pgdat->node_spanned_pages; i++) {
-			page = pgdat->node_mem_map + i;
+			page = pgdat_page_nr(pgdat, i);
 			if (PageReserved(page))
 				reservedpages++;
 		}