[PATCH] zoned vm counters: conversion of nr_writeback to per zone counter

Conversion of nr_writeback to per zone counter.

This removes the last page_state counter from arch/i386/mm/pgtable.c so we
drop the page_state from there.

[akpm@osdl.org: bugfix]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/i386/mm/pgtable.c

@@ -30,7 +30,6 @@ void show_mem(void)
 	struct page *page;
 	pg_data_t *pgdat;
 	unsigned long i;
-	struct page_state ps;
 	unsigned long flags;
 
 	printk(KERN_INFO "Mem-info:\n");
@@ -58,9 +57,9 @@ void show_mem(void)
 	printk(KERN_INFO "%d pages shared\n", shared);
 	printk(KERN_INFO "%d pages swap cached\n", cached);
 
-	get_page_state(&ps);
 	printk(KERN_INFO "%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
-	printk(KERN_INFO "%lu pages writeback\n", ps.nr_writeback);
+	printk(KERN_INFO "%lu pages writeback\n",
+					global_page_state(NR_WRITEBACK));
 	printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
 	printk(KERN_INFO "%lu pages slab\n", global_page_state(NR_SLAB));
 	printk(KERN_INFO "%lu pages pagetables\n",

drivers/base/node.c

@@ -49,9 +49,6 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
 	get_page_state_node(&ps, nid);
 	__get_zone_counts(&active, &inactive, &free, NODE_DATA(nid));
 
-	/* Check for negative values in these approximate counters */
-	if ((long)ps.nr_writeback < 0)
-		ps.nr_writeback = 0;
 
 	n = sprintf(buf, "\n"
 		       "Node %d MemTotal:     %8lu kB\n"
@@ -80,7 +77,7 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
 		       nid, K(i.totalram - i.totalhigh),
 		       nid, K(i.freeram - i.freehigh),
 		       nid, K(node_page_state(nid, NR_FILE_DIRTY)),
-		       nid, K(ps.nr_writeback),
+		       nid, K(node_page_state(nid, NR_WRITEBACK)),
 		       nid, K(node_page_state(nid, NR_FILE_PAGES)),
 		       nid, K(node_page_state(nid, NR_FILE_MAPPED)),
 		       nid, K(node_page_state(nid, NR_ANON_PAGES)),

fs/proc/proc_misc.c

@@ -191,7 +191,7 @@ static int meminfo_read_proc(char *page, char **start, off_t off,
 		K(i.totalswap),
 		K(i.freeswap),
 		K(global_page_state(NR_FILE_DIRTY)),
-		K(ps.nr_writeback),
+		K(global_page_state(NR_WRITEBACK)),
 		K(global_page_state(NR_ANON_PAGES)),
 		K(global_page_state(NR_FILE_MAPPED)),
 		K(global_page_state(NR_SLAB)),

include/linux/mmzone.h

@@ -54,6 +54,7 @@ enum zone_stat_item {
 	NR_SLAB,	/* Pages used by slab allocator */
 	NR_PAGETABLE,	/* used for pagetables */
 	NR_FILE_DIRTY,
+	NR_WRITEBACK,
 	NR_VM_ZONE_STAT_ITEMS };
 
 struct per_cpu_pages {

include/linux/page-flags.h

@@ -181,7 +181,7 @@
 	do {								\
 		if (!test_and_set_bit(PG_writeback,			\
 				&(page)->flags))			\
-			inc_page_state(nr_writeback);			\
+			inc_zone_page_state(page, NR_WRITEBACK);	\
 	} while (0)
 #define TestSetPageWriteback(page)					\
 	({								\
@@ -189,14 +189,14 @@
 		ret = test_and_set_bit(PG_writeback,			\
 					&(page)->flags);		\
 		if (!ret)						\
-			inc_page_state(nr_writeback);			\
+			inc_zone_page_state(page, NR_WRITEBACK);	\
 		ret;							\
 	})
 #define ClearPageWriteback(page)					\
 	do {								\
 		if (test_and_clear_bit(PG_writeback,			\
 				&(page)->flags))			\
-			dec_page_state(nr_writeback);			\
+			dec_zone_page_state(page, NR_WRITEBACK);	\
 	} while (0)
 #define TestClearPageWriteback(page)					\
 	({								\
@@ -204,7 +204,7 @@
 		ret = test_and_clear_bit(PG_writeback,			\
 				&(page)->flags);			\
 		if (ret)						\
-			dec_page_state(nr_writeback);			\
+			dec_zone_page_state(page, NR_WRITEBACK);	\
 		ret;							\
 	})
 

include/linux/vmstat.h

@@ -22,7 +22,6 @@
  * commented here.
  */
 struct page_state {
-	unsigned long nr_writeback;	/* Pages under writeback */
 	unsigned long nr_unstable;	/* NFS unstable pages */
 #define GET_PAGE_STATE_LAST nr_unstable
 

mm/page-writeback.c

@@ -113,7 +113,7 @@ static void get_writeback_state(struct writeback_state *wbs)
 	wbs->nr_unstable = read_page_state(nr_unstable);
 	wbs->nr_mapped = global_page_state(NR_FILE_MAPPED) +
 				global_page_state(NR_ANON_PAGES);
-	wbs->nr_writeback = read_page_state(nr_writeback);
+	wbs->nr_writeback = global_page_state(NR_WRITEBACK);
 }
 
 /*

mm/page_alloc.c

@@ -1315,7 +1315,7 @@ void show_free_areas(void)
 		active,
 		inactive,
 		global_page_state(NR_FILE_DIRTY),
-		ps.nr_writeback,
+		global_page_state(NR_WRITEBACK),
 		ps.nr_unstable,
 		nr_free_pages(),
 		global_page_state(NR_SLAB),

mm/vmstat.c

@@ -401,9 +401,9 @@ static char *vmstat_text[] = {
 	"nr_slab",
 	"nr_page_table_pages",
 	"nr_dirty",
+	"nr_writeback",
 
 	/* Page state */
-	"nr_writeback",
 	"nr_unstable",
 
 	"pgpgin",