Messages in this thread Patch in this message | | | From | Mandeep Singh Baines <> | Subject | [PATCH] dm: pass up rotational flag | Date | Wed, 25 May 2011 13:50:48 -0700 |
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Allow the NONROT flag to be passed through to linear mappings if all underlying device are non-rotational. Tools like ureadahead will schedule IOs differently based on the rotational flag.
With this patch, I see boot time go from 7.75 s to 7.46 s on my device.
Suggested-by: J. Richard Barnette <jrbarnette@chromium.org> Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Neil Brown <neilb@suse.de> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Jens Axboe <jaxboe@fusionio.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: dm-devel@redhat.com --- drivers/md/dm-table.c | 28 ++++++++++++++++++++++++++++ 1 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index cb8380c..40c6071 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1177,6 +1177,30 @@ static void dm_table_set_integrity(struct dm_table *t) blk_get_integrity(template_disk)); } +static int device_nonrot(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct request_queue *q = bdev_get_queue(dev->bdev); + + return q && blk_queue_nonrot(q); +} + +static bool dm_table_all_nonrot(struct dm_table *t) +{ + unsigned i = 0; + + /* Ensure that all underlying device are non rotational. */ + while (i < dm_table_get_num_targets(t)) { + struct dm_target *ti = dm_table_get_target(t, i++); + + if (!ti->type->iterate_devices || + !ti->type->iterate_devices(ti, device_nonrot, NULL)) + return false; + } + + return true; +} + void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, struct queue_limits *limits) { @@ -1189,6 +1213,10 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q); else queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); + if (!dm_table_all_nonrot(t)) + queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q); + else + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q); dm_table_set_integrity(t); -- 1.7.3.1
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