[PATCH 03/21] Convert nr_mapped to per zone counter

Christoph Lameter
2006-06-12T21:20:14Z

Subject: zoned vm counters: conversion of nr_mapped to per zone counter
From: Christoph Lameter <clameter@sgi.com>

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@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

Index: linux-2.6.17-rc6-cl/arch/i386/mm/pgtable.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/arch/i386/mm/pgtable.c 2006-06-05 17:57:02.000000000 -0700
+++ linux-2.6.17-rc6-cl/arch/i386/mm/pgtable.c 2006-06-12 12:57:23.381448638 -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);
}
Index: linux-2.6.17-rc6-cl/drivers/base/node.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/drivers/base/node.c 2006-06-12 12:42:42.797286410 -0700
+++ linux-2.6.17-rc6-cl/drivers/base/node.c 2006-06-12 12:57:23.382425140 -0700
@@ -54,8 +54,6 @@ static ssize_t node_read_meminfo(struct
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 +82,7 @@ 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(node_page_state(nid, NR_MAPPED)),
nid, K(ps.nr_slab));
n += hugetlb_report_node_meminfo(nid, buf + n);
return n;
Index: linux-2.6.17-rc6-cl/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/fs/proc/proc_misc.c 2006-06-12 12:42:48.170000806 -0700
+++ linux-2.6.17-rc6-cl/fs/proc/proc_misc.c 2006-06-12 12:57:23.383401642 -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-cl/include/linux/mmzone.h
===================================================================
--- linux-2.6.17-rc6-cl.orig/include/linux/mmzone.h 2006-06-12 12:54:33.238664762 -0700
+++ linux-2.6.17-rc6-cl/include/linux/mmzone.h 2006-06-12 12:57:23.383401642 -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 };

struct per_cpu_pages {
Index: linux-2.6.17-rc6-cl/mm/page_alloc.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/page_alloc.c 2006-06-12 12:54:33.240617767 -0700
+++ linux-2.6.17-rc6-cl/mm/page_alloc.c 2006-06-12 12:57:23.385354646 -0700
@@ -1409,7 +1409,7 @@ 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) {
Index: linux-2.6.17-rc6-cl/mm/page-writeback.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/page-writeback.c 2006-06-12 12:42:52.043784523 -0700
+++ linux-2.6.17-rc6-cl/mm/page-writeback.c 2006-06-12 12:57:23.386331148 -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-cl/mm/rmap.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/rmap.c 2006-06-12 12:42:52.051596540 -0700
+++ linux-2.6.17-rc6-cl/mm/rmap.c 2006-06-12 12:57:23.386331148 -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-cl/mm/vmscan.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/vmscan.c 2006-06-12 12:42:52.067220573 -0700
+++ linux-2.6.17-rc6-cl/mm/vmscan.c 2006-06-12 12:57:23.388284152 -0700
@@ -996,7 +996,7 @@ 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();
@@ -1081,7 +1081,7 @@ 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);

@@ -1416,7 +1416,7 @@ 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);
@@ -1558,7 +1558,7 @@ 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-cl/mm/vmstat.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/vmstat.c 2006-06-12 12:55:05.481785246 -0700
+++ linux-2.6.17-rc6-cl/mm/vmstat.c 2006-06-12 13:00:45.074036260 -0700
@@ -463,13 +463,13 @@ struct seq_operations fragmentation_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",