From: Jes Sorensen <jsorensen@xxxxxx>
Put request bytes into 8 buckets of requests, for read, write, and
discard.
Enable stats by writing 1 to /sys/block/<dev>/queue/histstat, disable
by writing 0.
Signed-off-by: Jes Sorensen <jsorensen@xxxxxx>
---
block/blk-mq.c | 52 ++++++++++++++++++++++++++++++++++++++++++
block/blk-stat.h | 1 +
block/blk-sysfs.c | 40 ++++++++++++++++++++++++++++++++
include/linux/blkdev.h | 7 ++++++
4 files changed, 100 insertions(+)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8a59bc0410a6..942ef6e1ed86 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -59,6 +59,52 @@ static int blk_mq_poll_stats_bkt(const struct request *rq)
return bucket;
}
+/*
+ * 8 buckets for each of read, write, and discard
+ */
+static int blk_dev_stats_bkt(const struct request *rq)
+{
+ int grp, bucket;
+
+ grp = op_stat_group(req_op(rq));
+
+ bucket = grp + 3*(ilog2(rq->io_bytes) - 9);
+
+ if (bucket < 0)
+ return -1;
+ else if (bucket >= BLK_DEV_STATS_BKTS)
+ return grp + BLK_DEV_STATS_BKTS - 3;
+
+ return bucket;
+}
+
+/*
+ * Copy out the stats to their official location
+ */
+static void blk_dev_stats_cb(struct blk_stat_callback *cb)
+{
+ struct request_queue *q = cb->data;
+ int bucket;
+
+ for (bucket = 0; bucket < BLK_DEV_STATS_BKTS; bucket++) {
+ if (cb->stat[bucket].nr_samples) {
+ q->dev_stat[bucket].size +=
+ cb->stat[bucket].size;
+ q->dev_stat[bucket].nr_samples +=
+ cb->stat[bucket].nr_samples;
+ }
+ }
+
+ if (!blk_stat_is_active(cb))
+ blk_stat_activate_msecs(cb, 100);
+}
+
+void blk_dev_stats_free(struct request_queue *q)
+{
+ blk_stat_remove_callback(q, q->dev_cb);
+ blk_stat_free_callback(q->dev_cb);
+}
+
/*
* Check if any of the ctx, dispatch list or elevator
* have pending work in this hardware queue.
@@ -2881,6 +2927,12 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
if (!q->nr_hw_queues)
goto err_hctxs;
+ q->dev_cb = blk_stat_alloc_callback(blk_dev_stats_cb,
+ blk_dev_stats_bkt,
+ BLK_DEV_STATS_BKTS, q);
+ if (!q->dev_cb)
+ goto err_hctxs;
+
INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
diff --git a/block/blk-stat.h b/block/blk-stat.h
index ea893c4a9af1..7f0c8b737a9d 100644
--- a/block/blk-stat.h
+++ b/block/blk-stat.h
@@ -168,4 +168,5 @@ void blk_rq_stat_add(struct blk_rq_stat *, u64, u64);
void blk_rq_stat_sum(struct blk_rq_stat *, struct blk_rq_stat *);
void blk_rq_stat_init(struct blk_rq_stat *);
+void blk_dev_stats_free(struct request_queue *q);
#endif
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index a16a02c52a85..81566432828d 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -530,6 +530,37 @@ static ssize_t queue_dax_show(struct request_queue *q, char *page)
return queue_var_show(blk_queue_dax(q), page);
}
+static ssize_t queue_histstat_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(test_bit(QUEUE_FLAG_HISTSTATS,
+ &q->queue_flags), page);
+}
+
+static ssize_t queue_histstat_store(struct request_queue *q, const char *page,
+ size_t size)
+{
+ unsigned long histstat_on;
+ ssize_t ret;
+
+ ret = queue_var_store(&histstat_on, page, size);
+ if (ret < 0)
+ return ret;
+
+ if (histstat_on) {
+ if (!blk_queue_flag_test_and_set(QUEUE_FLAG_HISTSTATS, q))
+ blk_stat_add_callback(q, q->dev_cb);
+ if (!blk_stat_is_active(q->dev_cb))
+ blk_stat_activate_msecs(q->dev_cb, 100);
+ } else {
+ if (test_bit(QUEUE_FLAG_HISTSTATS, &q->queue_flags)) {
+ blk_stat_remove_callback(q, q->dev_cb);
+ blk_queue_flag_clear(QUEUE_FLAG_HISTSTATS, q);
+ }
+ }
+
+ return ret;
+}
+
static struct queue_sysfs_entry queue_requests_entry = {
.attr = {.name = "nr_requests", .mode = 0644 },
.show = queue_requests_show,
@@ -728,6 +759,12 @@ static struct queue_sysfs_entry throtl_sample_time_entry = {
};
#endif
+static struct queue_sysfs_entry queue_histstat_entry = {
+ .attr = {.name = "histstat", .mode = 0644 },
+ .show = queue_histstat_show,
+ .store = queue_histstat_store,
+};
+
static struct attribute *queue_attrs[] = {
&queue_requests_entry.attr,
&queue_ra_entry.attr,
@@ -767,6 +804,7 @@ static struct attribute *queue_attrs[] = {
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
&throtl_sample_time_entry.attr,
#endif
+ &queue_histstat_entry.attr,
NULL,
};
@@ -856,6 +894,8 @@ static void __blk_release_queue(struct work_struct *work)
{
struct request_queue *q = container_of(work, typeof(*q), release_work);
+ blk_dev_stats_free(q);
+
if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 2716f239b56d..ed57518a15fb 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -53,6 +53,9 @@ struct blk_stat_callback;
/* Doing classic polling */
#define BLK_MQ_POLL_CLASSIC -1
+/* Must be consistent with blk_part_stats_bkt() */
+#define BLK_DEV_STATS_BKTS (3 * 8)
+
/*
* Maximum number of blkcg policies allowed to be registered concurrently.
* Defined here to simplify include dependency.
@@ -478,6 +481,9 @@ struct request_queue {
struct blk_stat_callback *poll_cb;
struct blk_rq_stat poll_stat[BLK_MQ_POLL_STATS_BKTS];
+ struct blk_stat_callback *dev_cb;
+ struct blk_rq_stat dev_stat[BLK_DEV_STATS_BKTS];
+
struct timer_list timeout;
struct work_struct timeout_work;
@@ -605,6 +611,7 @@ struct request_queue {
#define QUEUE_FLAG_SCSI_PASSTHROUGH 23 /* queue supports SCSI commands */
#define QUEUE_FLAG_QUIESCED 24 /* queue has been quiesced */
#define QUEUE_FLAG_PCI_P2PDMA 25 /* device supports PCI p2p requests */
+#define QUEUE_FLAG_HISTSTATS 26 /* Hist stats enabled if set */
#define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_SAME_COMP))
--
2.17.1
