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| author | Damien Le Moal <damien.lemoal@wdc.com> | 2019-09-05 18:51:31 +0900 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-09-05 19:52:33 -0600 |
| commit | 68c43f133a754c7bf5cb1018bb16dc0821cc43a1 (patch) | |
| tree | 79d8eba4264de5d90e3f8bedd2329e5802c94b6e /block/mq-deadline.c | |
| parent | 954b4a5ce4a806e7c284ce6b2659abdd03d0b6e2 (diff) | |
block: Introduce elevator features
Introduce the definition of elevator features through the
elevator_features flags in the elevator_type structure. Each flag can
represent a feature supported by an elevator. The first feature defined
by this patch is support for zoned block device sequential write
constraint with the flag ELEVATOR_F_ZBD_SEQ_WRITE, which is implemented
by the mq-deadline elevator using zone write locking.
Other possible features are IO priorities, write hints, latency targets
or single-LUN dual-actuator disks (for which the elevator could maintain
one LBA ordered list per actuator).
The required_elevator_features field is also added to the request_queue
structure to allow a device driver to specify elevator feature flags
that an elevator must support for the correct operation of the device
(e.g. device drivers for zoned block devices can have the
ELEVATOR_F_ZBD_SEQ_WRITE flag as a required feature).
The helper function blk_queue_required_elevator_features() is
defined for setting this new field.
With these two new fields in place, the elevator functions
elevator_match() and elevator_find() are modified to allow a user to set
only an elevator with a set of features that satisfies the device
required features. Elevators not matching the device requirements are
not shown in the device sysfs queue/scheduler file to prevent their use.
The "none" elevator can always be selected as before.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/mq-deadline.c')
| -rw-r--r-- | block/mq-deadline.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/block/mq-deadline.c b/block/mq-deadline.c index 35e84bc0ec8c..b490f47fd553 100644 --- a/block/mq-deadline.c +++ b/block/mq-deadline.c @@ -794,6 +794,7 @@ static struct elevator_type mq_deadline = { .elevator_attrs = deadline_attrs, .elevator_name = "mq-deadline", .elevator_alias = "deadline", + .elevator_features = ELEVATOR_F_ZBD_SEQ_WRITE, .elevator_owner = THIS_MODULE, }; MODULE_ALIAS("mq-deadline-iosched"); |