This patch adds io polling force controls to sysfs. Setting this knob
forces direct-io to always poll, even if the io does not specify the
HIPRI flag.
Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
---
block/blk-sysfs.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index dd93763..e3af748 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -347,6 +347,37 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page,
return ret;
}
+static ssize_t queue_poll_force_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(test_bit(QUEUE_FLAG_POLL_FORCE, &q->queue_flags),
+ page);
+}
+
+static ssize_t queue_poll_force_store(struct request_queue *q, const char *page,
+ size_t count)
+{
+ unsigned long poll_force_on;
+ ssize_t ret;
+
+ if (!q->mq_ops || !q->mq_ops->poll ||
+ !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+ return -EINVAL;
+
+ ret = queue_var_store(&poll_force_on, page, count);
+ if (ret < 0)
+ return ret;
+
+ spin_lock_irq(q->queue_lock);
+ if (poll_force_on)
+ queue_flag_set(QUEUE_FLAG_POLL_FORCE, q);
+ else
+ queue_flag_clear(QUEUE_FLAG_POLL_FORCE, 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,
@@ -478,6 +509,12 @@ static struct queue_sysfs_entry queue_poll_entry = {
.store = queue_poll_store,
};
+static struct queue_sysfs_entry queue_poll_force_entry = {
+ .attr = {.name = "io_poll_force", .mode = S_IRUGO | S_IWUSR },
+ .show = queue_poll_force_show,
+ .store = queue_poll_force_store,
+};
+
static struct attribute *default_attrs[] = {
&queue_requests_entry.attr,
&queue_ra_entry.attr,
@@ -503,6 +540,7 @@ static struct attribute *default_attrs[] = {
&queue_iostats_entry.attr,
&queue_random_entry.attr,
&queue_poll_entry.attr,
+ &queue_poll_force_entry.attr,
NULL,
};
--
2.5.0
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