On Sat, Aug 28, 2010 at 10:40:26AM +0800, Michael Rubin wrote:
> 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
It's silly to have the different names nr_dirtied and pages_cleaned
for the same item.
> 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));
> +}
The output format is quite different from /proc/vmstat.
Do we really need to "Node X", ":" and "times" decorations?
And the "_PAGES" in NR_FILE_PAGES_DIRTIED looks redundant to
the "_page" in node_page_state(). It's a bit long to be a pleasant
name. NR_FILE_DIRTIED/NR_CLEANED looks nicer.
> +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 */
How about the comments /* accumulated number of pages ... */?
Note that NR_CLEANED won't match NR_FILE_DIRTIED in long term because
it also accounts for anon pages, and does not account for dirty pages
that are truncated before they go writeback.
Thanks,
Fengguang
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