[PATCH] vm: add per-zone writeout counter
The VM is supposed to minimise the number of pages which get written off the
LRU (for IO scheduling efficiency, and for high reclaim-success rates). But
we don't actually have a clear way of showing how true this is.
So add `nr_vmscan_write' to /proc/vmstat and /proc/zoneinfo - the number of
pages which have been written by the vm scanner in this zone and globally.
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 7fa1cbe..1b0680c 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -58,6 +58,7 @@
NR_WRITEBACK,
NR_UNSTABLE_NFS, /* NFS unstable pages */
NR_BOUNCE,
+ NR_VMSCAN_WRITE,
#ifdef CONFIG_NUMA
NUMA_HIT, /* allocated in intended node */
NUMA_MISS, /* allocated in non intended node */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 87779dd..87d3409 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -19,6 +19,7 @@
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/highmem.h>
+#include <linux/vmstat.h>
#include <linux/file.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
@@ -370,7 +371,7 @@
/* synchronous write or broken a_ops? */
ClearPageReclaim(page);
}
-
+ inc_zone_page_state(page, NR_VMSCAN_WRITE);
return PAGE_SUCCESS;
}
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 490d8c1..69c6571 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -465,6 +465,7 @@
"nr_writeback",
"nr_unstable",
"nr_bounce",
+ "nr_vmscan_write",
#ifdef CONFIG_NUMA
"numa_hit",
