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block, bfq: retrieve independent access ranges from request queue

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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.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Rory Chen <rory.c.chen@seagate.com>
Signed-off-by: Rory Chen <rory.c.chen@seagate.com>
Signed-off-by: Federico Gavioli <f.gavioli97@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20230103145503.71712-7-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Federico Gavioli 2023-01-03 15:55:01 +01:00 committed by Jens Axboe
parent 8b7fd74111
commit 4fdb3b9f2a
2 changed files with 59 additions and 10 deletions
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61
block/bfq-iosched.c
View File

@ -1793,10 +1793,25 @@ static bool bfq_bfqq_higher_class_or_weight(struct bfq_queue *bfqq,
*/
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 (to keep incomplete mechanisms off).
*/
unsigned int i;
sector_t end;
/* no search needed if one or zero ranges present */
if (bfqd->num_actuators == 1)
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++) {
if (end >= bfqd->sector[i] &&
end < bfqd->sector[i] + bfqd->nr_sectors[i])
return i;
}
WARN_ONCE(true,
"bfq_actuator_index: bio sector out of ranges: end=%llu\n",
end);
return 0;
}
@ -7105,6 +7120,8 @@ 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)
@ -7147,12 +7164,38 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
bfqd->queue = q;
/*
* Multi-actuator support not complete yet, unconditionally
* set to only one actuator for the moment (to keep incomplete
* mechanisms off).
*/
bfqd->num_actuators = 1;
/*
* If the disk supports multiple actuators, copy independent
* access ranges from the request queue structure.
*/
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");
} else {
bfqd->num_actuators = ia_ranges->nr_ia_ranges;
for (i = 0; i < bfqd->num_actuators; i++) {
bfqd->sector[i] = ia_ranges->ia_range[i].sector;
bfqd->nr_sectors[i] =
ia_ranges->ia_range[i].nr_sectors;
}
}
}
/* Otherwise use single-actuator dev info */
if (bfqd->num_actuators == 1) {
bfqd->sector[0] = 0;
bfqd->nr_sectors[0] = get_capacity(q->disk);
}
spin_unlock_irq(&q->queue_lock);
INIT_LIST_HEAD(&bfqd->dispatch);

8
block/bfq-iosched.h
View File

@ -814,7 +814,13 @@ struct bfq_data {
* case of single-actuator drives.
*/
unsigned int num_actuators;
/*
* Disk independent access ranges for each actuator
* in this device.
*/
sector_t sector[BFQ_MAX_ACTUATORS];
sector_t nr_sectors[BFQ_MAX_ACTUATORS];
struct blk_independent_access_range ia_ranges[BFQ_MAX_ACTUATORS];
};
enum bfqq_state_flags {