[PATCHv2 5/7] zram: export new 'io_stat' sysfs attrs

Sergey Senozhatsky
2015-03-12T14:47:27Z

Per-device `zram<id>/io_stat' file provides accumulated I/O
statistics of a particular zram device in a format similar
to block layer statistics. The file consists of a single line
and represents the following stats (separated by whitespace):
failed_reads
failed_writes
invalid_io
notify_free

Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
Documentation/ABI/testing/sysfs-block-zram | 9 +++++++++
Documentation/blockdev/zram.txt | 12 ++++++++++++
drivers/block/zram/zram_drv.c | 20 ++++++++++++++++++++
3 files changed, 41 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index 91ad707..a7f622f 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -149,3 +149,12 @@ Description:
The compact file is write-only and trigger compaction for
allocator zrm uses. The allocator moves some objects so that
it could free fragment space.
+
+What: /sys/block/zram<id>/io_stat
+Date: August 2015
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The io_stat file is read-only and accumulates device's I/O
+ statistics not accounted by block layer. For example,
+ failed_reads, failed_writes, etc. File format is similar to
+ block layer statistics file format.
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index 5d5e8be..5ed4dd5 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -153,6 +153,18 @@ File /sys/block/zram<id>/stat
Represents block layer statistics. Read Documentation/block/stat.txt for
details.

+
+File /sys/block/zram<id>/io_stat
+
+The stat file represents device's I/O statistics not accounted by block
+layer and, thus, not available in zram<id>/stat file. It consists of a
+single line of text and contains the following stats separated by
+whitespace:
+ failed_reads
+ failed_writes
+ invalid_io
+ notify_free
+
9) Deactivate:
swapoff /dev/zram0
umount /dev/zram1
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 45319eb9..c02121f 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -384,6 +384,25 @@ static ssize_t compact_store(struct device *dev,
return len;
}

+static ssize_t io_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ ret = scnprintf(buf, PAGE_SIZE,
+ "%8llu %8llu %8llu %8llu\n",
+ (u64)atomic64_read(&zram->stats.failed_reads),
+ (u64)atomic64_read(&zram->stats.failed_writes),
+ (u64)atomic64_read(&zram->stats.invalid_io),
+ (u64)atomic64_read(&zram->stats.notify_free));
+ up_read(&zram->init_lock);
+
+ return ret;
+}
+
+static DEVICE_ATTR_RO(io_stat);
ZRAM_ATTR_RO(num_reads);
ZRAM_ATTR_RO(num_writes);
ZRAM_ATTR_RO(failed_reads);
@@ -1085,6 +1104,7 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_mem_used_max.attr,
&dev_attr_max_comp_streams.attr,
&dev_attr_comp_algorithm.attr,
+ &dev_attr_io_stat.attr,
NULL,
};

--
2.3.2.209.gd67f9d5