To help developers and applications gain visibility into writeback
behaviour adding two entries to /proc/vmstat.
# grep nr_dirtied /proc/vmstat
nr_dirtied 3747
# grep nr_cleaned /proc/vmstat
nr_cleaned 3618
In order to track the "cleaned" and "dirtied" counts we added two
vm_stat_items. Per memory node stats have been added also. So we can
see per node granularity:
# cat /sys/devices/system/node/node20/vmstat
Node 20 pages_cleaned: 0 times
Node 20 pages_dirtied: 0 times
Signed-off-by: Michael Rubin <mrubin@xxxxxxxxxx>
---
drivers/base/node.c | 14 ++++++++++++++
include/linux/mmzone.h | 2 ++
mm/page-writeback.c | 2 ++
mm/vmstat.c | 3 +++
4 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 2872e86..facd920 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -160,6 +160,18 @@ static ssize_t node_read_numastat(struct sys_device * dev,
}
static SYSDEV_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
+static ssize_t node_read_vmstat(struct sys_device *dev,
+ struct sysdev_attribute *attr, char *buf)
+{
+ int nid = dev->id;
+ return sprintf(buf,
+ "Node %d pages_cleaned: %lu times\n"
+ "Node %d pages_dirtied: %lu times\n",
+ nid, node_page_state(nid, NR_PAGES_CLEANED),
+ nid, node_page_state(nid, NR_FILE_PAGES_DIRTIED));
+}
+static SYSDEV_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
+
static ssize_t node_read_distance(struct sys_device * dev,
struct sysdev_attribute *attr, char * buf)
{
@@ -243,6 +255,7 @@ int register_node(struct node *node, int num, struct node *parent)
sysdev_create_file(&node->sysdev, &attr_meminfo);
sysdev_create_file(&node->sysdev, &attr_numastat);
sysdev_create_file(&node->sysdev, &attr_distance);
+ sysdev_create_file(&node->sysdev, &attr_vmstat);
scan_unevictable_register_node(node);
@@ -267,6 +280,7 @@ void unregister_node(struct node *node)
sysdev_remove_file(&node->sysdev, &attr_meminfo);
sysdev_remove_file(&node->sysdev, &attr_numastat);
sysdev_remove_file(&node->sysdev, &attr_distance);
+ sysdev_remove_file(&node->sysdev, &attr_vmstat);
scan_unevictable_unregister_node(node);
hugetlb_unregister_node(node); /* no-op, if memoryless node */
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 6e6e626..d42f179 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -104,6 +104,8 @@ enum zone_stat_item {
NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */
+ NR_FILE_PAGES_DIRTIED, /* number of times pages get dirtied */
+ NR_PAGES_CLEANED, /* number of times pages enter writeback */
#ifdef CONFIG_NUMA
NUMA_HIT, /* allocated in intended node */
NUMA_MISS, /* allocated in non intended node */
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index ae5f5d5..19bb8c0 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1126,6 +1126,7 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
{
if (mapping_cap_account_dirty(mapping)) {
__inc_zone_page_state(page, NR_FILE_DIRTY);
+ __inc_zone_page_state(page, NR_FILE_PAGES_DIRTIED);
__inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
task_dirty_inc(current);
task_io_account_write(PAGE_CACHE_SIZE);
@@ -1141,6 +1142,7 @@ EXPORT_SYMBOL(account_page_dirtied);
void account_page_writeback(struct page *page)
{
inc_zone_page_state(page, NR_WRITEBACK);
+ inc_zone_page_state(page, NR_PAGES_CLEANED);
}
EXPORT_SYMBOL(account_page_writeback);
diff --git a/mm/vmstat.c b/mm/vmstat.c
index f389168..8521475 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -732,6 +732,9 @@ static const char * const vmstat_text[] = {
"nr_isolated_anon",
"nr_isolated_file",
"nr_shmem",
+ "nr_dirtied",
+ "nr_cleaned",
+
#ifdef CONFIG_NUMA
"numa_hit",
"numa_miss",
--
1.7.1
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