Patch adds an association between iocontext ioprio and the ioprio of
a request. This feature is only enabled if a queue flag is set to
indicate that requests should have ioprio associated with them. The
queue flag is exposed as the req_prio queue sysfs entry.
Signed-off-by: Adam Mananzanares <adam.manzanares@xxxxxxxx>
---
Documentation/block/queue-sysfs.txt | 12 ++++++++++++
block/blk-core.c | 5 +++++
block/blk-sysfs.c | 32 ++++++++++++++++++++++++++++++++
include/linux/blkdev.h | 3 +++
4 files changed, 52 insertions(+)
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt
index 2a39040..3ca4e8f 100644
--- a/Documentation/block/queue-sysfs.txt
+++ b/Documentation/block/queue-sysfs.txt
@@ -144,6 +144,18 @@ For storage configurations that need to maximize distribution of completion
processing setting this option to '2' forces the completion to run on the
requesting cpu (bypassing the "group" aggregation logic).
+rq_ioc_prio (RW)
+----------------
+If this option is '1', and there is a valid iocontext associated with the
+issuing context, and the bio we are processing does not have a valid
+prio, then we save the prio value from the iocontext with the request.
+
+This feature can be combined with device drivers that are aware of prio
+values in order to handle prio accordingly. An example would be if the ata
+layer recognizes prio and creates ata commands with high priority and sends
+them to the device. If the hardware supports priorities for commands then
+this has the potential to speed up response times for high priority IO.
+
scheduler (RW)
--------------
When read, this file will display the current and available IO schedulers
diff --git a/block/blk-core.c b/block/blk-core.c
index 14d7c07..2e740c4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -33,6 +33,7 @@
#include <linux/ratelimit.h>
#include <linux/pm_runtime.h>
#include <linux/blk-cgroup.h>
+#include <linux/ioprio.h>
#define CREATE_TRACE_POINTS
#include <trace/events/block.h>
@@ -1648,6 +1649,7 @@ unsigned int blk_plug_queued_count(struct request_queue *q)
void init_request_from_bio(struct request *req, struct bio *bio)
{
+ struct io_context *ioc = rq_ioc(bio);
req->cmd_type = REQ_TYPE_FS;
req->cmd_flags |= bio->bi_opf & REQ_COMMON_MASK;
@@ -1657,6 +1659,9 @@ void init_request_from_bio(struct request *req, struct bio *bio)
req->errors = 0;
req->__sector = bio->bi_iter.bi_sector;
req->ioprio = bio_prio(bio);
+ if (blk_queue_rq_ioc_prio(req->q) && !ioprio_valid(req->ioprio) && ioc)
+ req->ioprio = ioc->ioprio;
+
blk_rq_bio_prep(req->q, req, bio);
}
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 9cc8d7c..a9c5105 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -384,6 +384,31 @@ 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_rq_ioc_prio_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(blk_queue_rq_ioc_prio(q), page);
+}
+
+static ssize_t queue_rq_ioc_prio_store(struct request_queue *q,
+ const char *page, size_t count)
+{
+ unsigned long rq_ioc_prio_on;
+ ssize_t ret;
+
+ ret = queue_var_store(&rq_ioc_prio_on, page, count);
+ if (ret < 0)
+ return ret;
+
+ spin_lock_irq(q->queue_lock);
+ if (rq_ioc_prio_on)
+ queue_flag_set(QUEUE_FLAG_RQ_IOC_PRIO, q);
+ else
+ queue_flag_clear(QUEUE_FLAG_RQ_IOC_PRIO, q);
+ spin_unlock_irq(q->queue_lock);
+
+ return ret;
+}
+
static struct queue_sysfs_entry queue_requests_entry = {
.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
.show = queue_requests_show,
@@ -526,6 +551,12 @@ static struct queue_sysfs_entry queue_dax_entry = {
.show = queue_dax_show,
};
+static struct queue_sysfs_entry queue_rq_ioc_prio_entry = {
+ .attr = {.name = "rq_ioc_prio", .mode = S_IRUGO | S_IWUSR },
+ .show = queue_rq_ioc_prio_show,
+ .store = queue_rq_ioc_prio_store,
+};
+
static struct attribute *default_attrs[] = {
&queue_requests_entry.attr,
&queue_ra_entry.attr,
@@ -553,6 +584,7 @@ static struct attribute *default_attrs[] = {
&queue_poll_entry.attr,
&queue_wc_entry.attr,
&queue_dax_entry.attr,
+ &queue_rq_ioc_prio_entry.attr,
NULL,
};
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c47c358..63b842a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -505,6 +505,7 @@ struct request_queue {
#define QUEUE_FLAG_FUA 24 /* device supports FUA writes */
#define QUEUE_FLAG_FLUSH_NQ 25 /* flush not queueuable */
#define QUEUE_FLAG_DAX 26 /* device supports DAX */
+#define QUEUE_FLAG_RQ_IOC_PRIO 27 /* Use iocontext ioprio */
#define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_STACKABLE) | \
@@ -595,6 +596,8 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
#define blk_queue_secure_erase(q) \
(test_bit(QUEUE_FLAG_SECERASE, &(q)->queue_flags))
#define blk_queue_dax(q) test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
+#define blk_queue_rq_ioc_prio(q) \
+ test_bit(QUEUE_FLAG_RQ_IOC_PRIO, &(q)->queue_flags)
#define blk_noretry_request(rq) \
((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
--
2.1.4
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