From: Federico Gavioli <f.gavioli97@xxxxxxxxx>
This patch implements the code to gather the content of the
independent_access_ranges structure from the request_queue and copy
it into the queue's bfq_data. This copy is done at queue initialization.
We copy the access ranges into the bfq_data to avoid taking the queue
lock each time we access the ranges.
This implementation, however, puts a limit to the maximum independent
ranges supported by the scheduler. Such a limit is equal to the constant
BFQ_MAX_ACTUATORS. This limit was placed to avoid the allocation of
dynamic memory.
Co-developed-by: Rory Chen <rory.c.chen@xxxxxxxxxxx>
Signed-off-by: Rory Chen <rory.c.chen@xxxxxxxxxxx>
Signed-off-by: Federico Gavioli <f.gavioli97@xxxxxxxxx>
Signed-off-by: Paolo Valente <paolo.valente@xxxxxxxxxx>
---
block/bfq-iosched.c | 54 ++++++++++++++++++++++++++++++++++++++-------
block/bfq-iosched.h | 5 +++++
2 files changed, 51 insertions(+), 8 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 7c9b5cae05b5..d0109bfc2ed0 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1831,10 +1831,26 @@ static bool bfq_bfqq_higher_class_or_weight(struct bfq_queue *bfqq,
/* get the index of the actuator that will serve bio */
static unsigned int bfq_actuator_index(struct bfq_data *bfqd, struct bio *bio)
{
- /*
- * Multi-actuator support not complete yet, so always return 0
- * for the moment.
- */
+ struct blk_independent_access_range *iar;
+ unsigned int i;
+ sector_t end;
+
+ /* no search needed if one or zero ranges present */
+ if (bfqd->num_actuators < 2)
+ return 0;
+
+ /* bio_end_sector(bio) gives the sector after the last one */
+ end = bio_end_sector(bio) - 1;
+
+ for (i = 0; i < bfqd->num_actuators; i++) {
+ iar = &(bfqd->ia_ranges[i]);
+ if (end >= iar->sector && end < iar->sector + iar->nr_sectors)
+ return i;
+ }
+
+ WARN_ONCE(true,
+ "bfq_actuator_index: bio sector out of ranges: end=%llu\n",
+ end);
return 0;
}
@@ -2479,7 +2495,6 @@ static void bfq_remove_request(struct request_queue *q,
if (rq->cmd_flags & REQ_META)
bfqq->meta_pending--;
-
}
static bool bfq_bio_merge(struct request_queue *q, struct bio *bio,
@@ -7137,6 +7152,8 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
{
struct bfq_data *bfqd;
struct elevator_queue *eq;
+ unsigned int i;
+ struct blk_independent_access_ranges *ia_ranges = q->disk->ia_ranges;
eq = elevator_alloc(q, e);
if (!eq)
@@ -7180,10 +7197,31 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
bfqd->queue = q;
/*
- * Multi-actuator support not complete yet, default to single
- * actuator for the moment.
+ * If the disk supports multiple actuators, we copy the independent
+ * access ranges from the request queue structure.
*/
- bfqd->num_actuators = 1;
+ spin_lock_irq(&q->queue_lock);
+ if (ia_ranges) {
+ /*
+ * Check if the disk ia_ranges size exceeds the current bfq
+ * actuator limit.
+ */
+ if (ia_ranges->nr_ia_ranges > BFQ_MAX_ACTUATORS) {
+ pr_crit("nr_ia_ranges higher than act limit: iars=%d, max=%d.\n",
+ ia_ranges->nr_ia_ranges, BFQ_MAX_ACTUATORS);
+ pr_crit("Falling back to single actuator mode.\n");
+ bfqd->num_actuators = 0;
+ } else {
+ bfqd->num_actuators = ia_ranges->nr_ia_ranges;
+
+ for (i = 0; i < bfqd->num_actuators; i++)
+ bfqd->ia_ranges[i] = ia_ranges->ia_range[i];
+ }
+ } else {
+ bfqd->num_actuators = 0;
+ }
+
+ spin_unlock_irq(&q->queue_lock);
INIT_LIST_HEAD(&bfqd->dispatch);
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 5fca86a82411..326d68d65cc9 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -815,6 +815,11 @@ struct bfq_data {
*/
unsigned int num_actuators;
+ /*
+ * Disk independent access ranges for each actuator
+ * in this device.
+ */
+ struct blk_independent_access_range ia_ranges[BFQ_MAX_ACTUATORS];
};
enum bfqq_state_flags {
--
2.20.1
