[PATCH 03/14] Convert nr_mapped to per zone counter

Christoph Lameter
2006-06-21T18:09:10Z

nr_mapped is important because it allows a determination of 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_FILE_MAPPED (the anonymous pages will be split
off from NR_MAPPED in the next patch).

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>

Index: linux-2.6.17-mm1/arch/i386/mm/pgtable.c
===================================================================
--- linux-2.6.17-mm1.orig/arch/i386/mm/pgtable.c 2006-06-17 18:49:35.000000000 -0700
+++ linux-2.6.17-mm1/arch/i386/mm/pgtable.c 2006-06-21 07:34:08.374880266 -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_FILE_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-mm1/drivers/base/node.c
===================================================================
--- linux-2.6.17-mm1.orig/drivers/base/node.c 2006-06-17 18:49:35.000000000 -0700
+++ linux-2.6.17-mm1/drivers/base/node.c 2006-06-21 07:34:08.375856768 -0700
@@ -53,8 +53,6 @@ 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;

@@ -83,7 +81,7 @@ 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_FILE_MAPPED)),
nid, K(ps.nr_slab));
n += hugetlb_report_node_meminfo(nid, buf + n);
return n;
Index: linux-2.6.17-mm1/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.17-mm1.orig/fs/proc/proc_misc.c 2006-06-17 18:49:35.000000000 -0700
+++ linux-2.6.17-mm1/fs/proc/proc_misc.c 2006-06-21 07:34:08.376833270 -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_FILE_MAPPED)),
K(ps.nr_slab),
K(allowed),
K(committed),
Index: linux-2.6.17-mm1/include/linux/mmzone.h
===================================================================
--- linux-2.6.17-mm1.orig/include/linux/mmzone.h 2006-06-21 07:33:56.667598796 -0700
+++ linux-2.6.17-mm1/include/linux/mmzone.h 2006-06-21 07:34:08.377809772 -0700
@@ -48,6 +48,9 @@ struct zone_padding {
#endif

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

struct per_cpu_pages {
Index: linux-2.6.17-mm1/mm/page_alloc.c
===================================================================
--- linux-2.6.17-mm1.orig/mm/page_alloc.c 2006-06-21 07:33:56.668575298 -0700
+++ linux-2.6.17-mm1/mm/page_alloc.c 2006-06-21 07:34:08.379762776 -0700
@@ -1314,7 +1314,7 @@ void show_free_areas(void)
ps.nr_unstable,
nr_free_pages(),
ps.nr_slab,
- ps.nr_mapped,
+ global_page_state(NR_FILE_MAPPED),
ps.nr_page_table_pages);

for_each_zone(zone) {
Index: linux-2.6.17-mm1/mm/page-writeback.c
===================================================================
--- linux-2.6.17-mm1.orig/mm/page-writeback.c 2006-06-17 18:49:35.000000000 -0700
+++ linux-2.6.17-mm1/mm/page-writeback.c 2006-06-21 07:34:08.379762776 -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_FILE_MAPPED);
wbs->nr_writeback = read_page_state(nr_writeback);
}

Index: linux-2.6.17-mm1/mm/rmap.c
===================================================================
--- linux-2.6.17-mm1.orig/mm/rmap.c 2006-06-17 18:49:35.000000000 -0700
+++ linux-2.6.17-mm1/mm/rmap.c 2006-06-21 07:34:08.380739278 -0700
@@ -493,7 +493,7 @@ 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_FILE_MAPPED);
}

/**
@@ -537,7 +537,7 @@ 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_FILE_MAPPED);
}

/**
@@ -569,7 +569,7 @@ 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_FILE_MAPPED);
}
}

Index: linux-2.6.17-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.17-mm1.orig/mm/vmscan.c 2006-06-17 18:49:35.000000000 -0700
+++ linux-2.6.17-mm1/mm/vmscan.c 2006-06-21 07:35:39.744211663 -0700
@@ -972,7 +972,7 @@ 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_FILE_MAPPED);
sc.nr_scanned = 0;
if (!priority)
disable_swap_token();
@@ -1062,7 +1062,7 @@ 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_FILE_MAPPED);

inc_page_state(pageoutrun);

@@ -1412,7 +1412,7 @@ 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_FILE_MAPPED),
.swap_cluster_max = max_t(unsigned long, nr_pages,
SWAP_CLUSTER_MAX),
.gfp_mask = gfp_mask,
Index: linux-2.6.17-mm1/mm/vmstat.c
===================================================================
--- linux-2.6.17-mm1.orig/mm/vmstat.c 2006-06-21 07:33:56.673457808 -0700
+++ linux-2.6.17-mm1/mm/vmstat.c 2006-06-21 07:34:08.382692282 -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",