Re: [PATCH] convert uses of ZONE_HIGHMEM to is_highmem

[Andy Whitcroft]

akpm@xxxxxxxx wrote:
> 
> Andy Whitcroft <apw@xxxxxxxxxxxx> wrote:
> >
> > As the comments in mmzone.h indicate is_highmem() is designed to
> > reduce the proliferation of the constant ZONE_HIGHMEM.  This patch
> > updates three references to ZONE_HIGHMEM to use is_highmem().
> > None appear to be on critical paths.
> > 
> > Revision: $Rev: 305 $ 
[...]
> Fair enough.
> 
> >  #ifdef CONFIG_HIGHMEM
> >  unsigned int nr_free_highpages (void)
> >  {
> > -	pg_data_t *pgdat;
> > +	struct zone *zone;
> >  	unsigned int pages = 0;
> >  
> > -	for_each_pgdat(pgdat)
> > -		pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages;
> > +	for_each_zone(zone)
> > +		if (is_highmem(zone))
> > +			pages += zone->free_pages;
> 
> but that's slower.

Fair point.  This patch only changes the first which is inialisation
only and the last which is the same code via inline.  The other
I'll hold onto and think about more.

-apw

=== 8< ===
As the comments in mmzone.h indicate is_highmem() is designed to
reduce the proliferation of the constant ZONE_HIGHMEM.  This patch
updates references to ZONE_HIGHMEM to use is_highmem().  None appear
to be on critical paths.

Revision: $Rev: 377 $

Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxx>

---
 arch/i386/mm/discontig.c |   17 +++++++++++------
 mm/page_alloc.c          |    2 +-
 2 files changed, 12 insertions(+), 7 deletions(-)

diff -upN reference/arch/i386/mm/discontig.c current/arch/i386/mm/discontig.c
--- reference/arch/i386/mm/discontig.c	2004-06-25 22:26:03.000000000 +0100
+++ current/arch/i386/mm/discontig.c	2004-07-07 18:10:15.000000000 +0100
@@ -409,17 +409,22 @@ void __init zone_sizes_init(void)
 void __init set_highmem_pages_init(int bad_ppro) 
 {
 #ifdef CONFIG_HIGHMEM
-	int nid;
+	struct zone *zone;
 
-	for (nid = 0; nid < numnodes; nid++) {
+	for_each_zone(zone) {
 		unsigned long node_pfn, node_high_size, zone_start_pfn;
 		struct page * zone_mem_map;
 		
-		node_high_size = NODE_DATA(nid)->node_zones[ZONE_HIGHMEM].spanned_pages;
-		zone_mem_map = NODE_DATA(nid)->node_zones[ZONE_HIGHMEM].zone_mem_map;
-		zone_start_pfn = NODE_DATA(nid)->node_zones[ZONE_HIGHMEM].zone_start_pfn;
+		if (!is_highmem(zone))
+			continue;
+
+		printk("Initializing %s for node %d\n", zone->name,
+			zone->zone_pgdat->node_id);
+
+		node_high_size = zone->spanned_pages;
+		zone_mem_map = zone->zone_mem_map;
+		zone_start_pfn = zone->zone_start_pfn;
 
-		printk("Initializing highpages for node %d\n", nid);
 		for (node_pfn = 0; node_pfn < node_high_size; node_pfn++) {
 			one_highpage_init((struct page *)(zone_mem_map + node_pfn),
 					  zone_start_pfn + node_pfn, bad_ppro);
diff -upN reference/mm/page_alloc.c current/mm/page_alloc.c
--- reference/mm/page_alloc.c	2004-07-07 18:08:56.000000000 +0100
+++ current/mm/page_alloc.c	2004-07-07 18:10:15.000000000 +0100
@@ -1421,7 +1421,7 @@ void __init memmap_init_zone(struct page
 		INIT_LIST_HEAD(&page->lru);
 #ifdef WANT_PAGE_VIRTUAL
 		/* The shift won't overflow because ZONE_NORMAL is below 4G. */
-		if (zone != ZONE_HIGHMEM)
+		if (!is_highmem(zone))
 			set_page_address(page, __va(start_pfn << PAGE_SHIFT));
 #endif
 		start_pfn++;
-
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