[PATCH 03/14] Conversion of nr_mapped to per zone counter

From: Christoph Lameter
Date: Thu Jun 08 2006 - 19:02:18 EST


Conversion of nr_mapped to a per zone counter

nr_mapped is important because it allows a determination how many pages of a
zone are not mapped, which would allow a more efficient means of determining
when we need to reclaim memory in a zone.

We take the nr_mapped field out of the page state structure and
define a new per zone counter named NR_MAPPED.

We replace the use of nr_mapped in various kernel locations. This avoids
the looping over all processors in try_to_free_pages(), writeback, reclaim
(swap + zone reclaim).

Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

Index: linux-2.6.17-rc6-mm1/drivers/base/node.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/drivers/base/node.c 2006-06-08 15:20:05.426540998 -0700
+++ linux-2.6.17-rc6-mm1/drivers/base/node.c 2006-06-08 15:44:58.889749567 -0700
@@ -44,18 +44,18 @@ static ssize_t node_read_meminfo(struct
unsigned long inactive;
unsigned long active;
unsigned long free;
+ unsigned long nr_mapped;

si_meminfo_node(&i, nid);
get_page_state_node(&ps, nid);
__get_zone_counts(&active, &inactive, &free, NODE_DATA(nid));
+ nr_mapped = node_page_state(nid, NR_MAPPED);

/* Check for negative values in these approximate counters */
if ((long)ps.nr_dirty < 0)
ps.nr_dirty = 0;
if ((long)ps.nr_writeback < 0)
ps.nr_writeback = 0;
- if ((long)ps.nr_mapped < 0)
- ps.nr_mapped = 0;
if ((long)ps.nr_slab < 0)
ps.nr_slab = 0;

@@ -84,7 +84,7 @@ static ssize_t node_read_meminfo(struct
nid, K(i.freeram - i.freehigh),
nid, K(ps.nr_dirty),
nid, K(ps.nr_writeback),
- nid, K(ps.nr_mapped),
+ nid, K(nr_mapped),
nid, K(ps.nr_slab));
n += hugetlb_report_node_meminfo(nid, buf + n);
return n;
Index: linux-2.6.17-rc6-mm1/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/fs/proc/proc_misc.c 2006-06-08 15:20:08.334564156 -0700
+++ linux-2.6.17-rc6-mm1/fs/proc/proc_misc.c 2006-06-08 15:44:58.890726069 -0700
@@ -190,7 +190,7 @@ static int meminfo_read_proc(char *page,
K(i.freeswap),
K(ps.nr_dirty),
K(ps.nr_writeback),
- K(ps.nr_mapped),
+ K(global_page_state(NR_MAPPED)),
K(ps.nr_slab),
K(allowed),
K(committed),
Index: linux-2.6.17-rc6-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/mm/vmscan.c 2006-06-08 15:20:11.595104562 -0700
+++ linux-2.6.17-rc6-mm1/mm/vmscan.c 2006-06-08 15:44:58.891702571 -0700
@@ -997,7 +997,7 @@ unsigned long try_to_free_pages(struct z
}

for (priority = DEF_PRIORITY; priority >= 0; priority--) {
- sc.nr_mapped = read_page_state(nr_mapped);
+ sc.nr_mapped = global_page_state(NR_MAPPED);
sc.nr_scanned = 0;
if (!priority)
disable_swap_token();
@@ -1082,7 +1082,7 @@ loop_again:
total_scanned = 0;
nr_reclaimed = 0;
sc.may_writepage = !laptop_mode,
- sc.nr_mapped = read_page_state(nr_mapped);
+ sc.nr_mapped = global_page_state(NR_MAPPED);

inc_page_state(pageoutrun);

@@ -1417,7 +1417,7 @@ unsigned long shrink_all_memory(unsigned
for (prio = DEF_PRIORITY; prio >= 0; prio--) {
unsigned long nr_to_scan = nr_pages - ret;

- sc.nr_mapped = read_page_state(nr_mapped);
+ sc.nr_mapped = global_page_state(NR_MAPPED);
sc.nr_scanned = 0;

ret += shrink_all_zones(nr_to_scan, prio, pass, &sc);
@@ -1559,7 +1559,7 @@ static int __zone_reclaim(struct zone *z
struct scan_control sc = {
.may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
.may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP),
- .nr_mapped = read_page_state(nr_mapped),
+ .nr_mapped = global_page_state(NR_MAPPED),
.swap_cluster_max = max_t(unsigned long, nr_pages,
SWAP_CLUSTER_MAX),
.gfp_mask = gfp_mask,
Index: linux-2.6.17-rc6-mm1/mm/page-writeback.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/mm/page-writeback.c 2006-06-08 15:20:11.553114973 -0700
+++ linux-2.6.17-rc6-mm1/mm/page-writeback.c 2006-06-08 15:44:58.892679074 -0700
@@ -111,7 +111,7 @@ static void get_writeback_state(struct w
{
wbs->nr_dirty = read_page_state(nr_dirty);
wbs->nr_unstable = read_page_state(nr_unstable);
- wbs->nr_mapped = read_page_state(nr_mapped);
+ wbs->nr_mapped = global_page_state(NR_MAPPED);
wbs->nr_writeback = read_page_state(nr_writeback);
}

Index: linux-2.6.17-rc6-mm1/mm/page_alloc.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/mm/page_alloc.c 2006-06-08 15:44:55.859663761 -0700
+++ linux-2.6.17-rc6-mm1/mm/page_alloc.c 2006-06-08 15:44:58.893655576 -0700
@@ -1815,7 +1815,7 @@ void show_free_areas(void)
ps.nr_unstable,
nr_free_pages(),
ps.nr_slab,
- ps.nr_mapped,
+ global_page_state(NR_MAPPED),
ps.nr_page_table_pages);

for_each_zone(zone) {
@@ -2801,13 +2801,13 @@ struct seq_operations zoneinfo_op = {

static char *vmstat_text[] = {
/* Zoned VM counters */
+ "nr_mapped",

/* Page state */
"nr_dirty",
"nr_writeback",
"nr_unstable",
"nr_page_table_pages",
- "nr_mapped",
"nr_slab",

"pgpgin",
Index: linux-2.6.17-rc6-mm1/mm/rmap.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/mm/rmap.c 2006-06-08 15:20:11.579480529 -0700
+++ linux-2.6.17-rc6-mm1/mm/rmap.c 2006-06-08 15:44:58.894632078 -0700
@@ -455,7 +455,7 @@ static void __page_set_anon_rmap(struct
* nr_mapped state can be updated without turning off
* interrupts because it is not modified via interrupt.
*/
- __inc_page_state(nr_mapped);
+ __inc_zone_page_state(page, NR_MAPPED);
}

/**
@@ -499,7 +499,7 @@ void page_add_new_anon_rmap(struct page
void page_add_file_rmap(struct page *page)
{
if (atomic_inc_and_test(&page->_mapcount))
- __inc_page_state(nr_mapped);
+ __inc_zone_page_state(page, NR_MAPPED);
}

/**
@@ -531,7 +531,7 @@ void page_remove_rmap(struct page *page)
*/
if (page_test_and_clear_dirty(page))
set_page_dirty(page);
- __dec_page_state(nr_mapped);
+ __dec_zone_page_state(page, NR_MAPPED);
}
}

Index: linux-2.6.17-rc6-mm1/include/linux/mmzone.h
===================================================================
--- linux-2.6.17-rc6-mm1.orig/include/linux/mmzone.h 2006-06-08 15:42:25.204930191 -0700
+++ linux-2.6.17-rc6-mm1/include/linux/mmzone.h 2006-06-08 15:44:58.895608580 -0700
@@ -47,6 +47,9 @@ struct zone_padding {
#endif

enum zone_stat_item {
+ NR_MAPPED, /* mapped into pagetables.
+ only modified from process context */
+
NR_STAT_ITEMS };

#ifdef CONFIG_SMP
Index: linux-2.6.17-rc6-mm1/include/linux/page-flags.h
===================================================================
--- linux-2.6.17-rc6-mm1.orig/include/linux/page-flags.h 2006-06-08 15:42:25.205906693 -0700
+++ linux-2.6.17-rc6-mm1/include/linux/page-flags.h 2006-06-08 15:44:58.896585082 -0700
@@ -123,8 +123,6 @@ struct page_state {
unsigned long nr_writeback; /* Pages under writeback */
unsigned long nr_unstable; /* NFS unstable pages */
unsigned long nr_page_table_pages;/* Pages used for pagetables */
- unsigned long nr_mapped; /* mapped into pagetables.
- * only modified from process context */
unsigned long nr_slab; /* In slab */
#define GET_PAGE_STATE_LAST nr_slab

Index: linux-2.6.17-rc6-mm1/mm/swap_prefetch.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/mm/swap_prefetch.c 2006-06-08 15:20:11.590222051 -0700
+++ linux-2.6.17-rc6-mm1/mm/swap_prefetch.c 2006-06-08 15:44:58.896585082 -0700
@@ -394,7 +394,7 @@ static int prefetch_suitable(void)
* even if the slab is being allocated on a remote node. This
* would be expensive to fix and not of great significance.
*/
- limit = ps.nr_mapped + ps.nr_slab + ps.nr_dirty +
+ limit = global_page_state(NR_MAPPED) + ps.nr_slab + ps.nr_dirty +
ps.nr_unstable + total_swapcache_pages;
if (limit > ns->prefetch_watermark) {
node_clear(node, sp_stat.prefetch_nodes);
Index: linux-2.6.17-rc6-mm1/arch/i386/mm/pgtable.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/arch/i386/mm/pgtable.c 2006-06-05 17:57:02.000000000 -0700
+++ linux-2.6.17-rc6-mm1/arch/i386/mm/pgtable.c 2006-06-08 15:45:17.903220642 -0700
@@ -61,7 +61,7 @@ void show_mem(void)
get_page_state(&ps);
printk(KERN_INFO "%lu pages dirty\n", ps.nr_dirty);
printk(KERN_INFO "%lu pages writeback\n", ps.nr_writeback);
- printk(KERN_INFO "%lu pages mapped\n", ps.nr_mapped);
+ printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_MAPPED));
printk(KERN_INFO "%lu pages slab\n", ps.nr_slab);
printk(KERN_INFO "%lu pages pagetables\n", ps.nr_page_table_pages);
}
-
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