We will track the size and latency of each io, which could make people
suffer from the additional overhead if they don't need the statistics.
So introduce a specific sysfs node to enable/disable the tracking.
Reviewed-by: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxx>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-block | 9 +++++++++
Documentation/block/queue-sysfs.rst | 5 +++++
block/blk-sysfs.c | 3 +++
include/linux/blkdev.h | 2 ++
4 files changed, 19 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index e34cdeeeb9d4..503314efec13 100644
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -316,3 +316,12 @@ Description:
does not complete in this time then the block driver timeout
handler is invoked. That timeout handler can decide to retry
the request, to fail it or to start a device recovery strategy.
+
+What: /sys/block/<disk>/queue/io_extra_stats
+Date: January 2021
+Contact: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
+Description:
+ Indicates if people want to know the extra statistics (I/O
+ size and I/O latency) from /sys/block/<disk>/io_latency
+ and /sys/block/<disk>/io_size. The value is 0 by default,
+ set if the extra statistics are needed.
diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 2638d3446b79..28ffce653eb1 100644
--- a/Documentation/block/queue-sysfs.rst
+++ b/Documentation/block/queue-sysfs.rst
@@ -99,6 +99,11 @@ iostats (RW)
This file is used to control (on/off) the iostats accounting of the
disk.
+io_extra_stats (RW)
+-------------------
+This file is used to control (on/off) the additional accounting of the
+io size and io latency of disk.
+
logical_block_size (RO)
-----------------------
This is the logical block size of the device, in bytes.
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index b513f1683af0..ed31938e89fe 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -287,6 +287,7 @@ queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
+QUEUE_SYSFS_BIT_FNS(io_extra_stats, IO_EXTRA_STAT, 0);
QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
#undef QUEUE_SYSFS_BIT_FNS
@@ -613,6 +614,7 @@ static struct queue_sysfs_entry queue_hw_sector_size_entry = {
QUEUE_RW_ENTRY(queue_nonrot, "rotational");
QUEUE_RW_ENTRY(queue_iostats, "iostats");
+QUEUE_RW_ENTRY(queue_io_extra_stats, "io_extra_stats");
QUEUE_RW_ENTRY(queue_random, "add_random");
QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
@@ -647,6 +649,7 @@ static struct attribute *queue_attrs[] = {
&queue_nomerges_entry.attr,
&queue_rq_affinity_entry.attr,
&queue_iostats_entry.attr,
+ &queue_io_extra_stats_entry.attr,
&queue_stable_writes_entry.attr,
&queue_random_entry.attr,
&queue_poll_entry.attr,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0dea268bd61b..62881db2004f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -621,6 +621,7 @@ struct request_queue {
#define QUEUE_FLAG_RQ_ALLOC_TIME 27 /* record rq->alloc_time_ns */
#define QUEUE_FLAG_HCTX_ACTIVE 28 /* at least one blk-mq hctx is active */
#define QUEUE_FLAG_NOWAIT 29 /* device supports NOWAIT */
+#define QUEUE_FLAG_IO_EXTRA_STAT 30 /* extra IO accounting for size and latency */
#define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_SAME_COMP) | \
@@ -641,6 +642,7 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
#define blk_queue_stable_writes(q) \
test_bit(QUEUE_FLAG_STABLE_WRITES, &(q)->queue_flags)
#define blk_queue_io_stat(q) test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
+#define blk_queue_io_extra_stat(q) test_bit(QUEUE_FLAG_IO_EXTRA_STAT, &(q)->queue_flags)
#define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
#define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
#define blk_queue_zone_resetall(q) \
--
2.17.1
