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authorMandeep Singh Baines <msb@chromium.org>2011-10-31 20:18:50 +0000
committerAlasdair G Kergon <agk@redhat.com>2011-10-31 20:18:50 +0000
commit4693c9668fdcec229825b3763876b4744f9e6d5e (patch)
tree683d07005d06c3e25bbec25b910567275f0bb9d1
parentc3b92c8787367a8bb53d57d9789b558f1295cc96 (diff)
dm table: propagate non rotational flag
Allow QUEUE_FLAG_NONROT to propagate up the device stack if all underlying devices 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> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: Jens Axboe <jaxboe@fusionio.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: dm-devel@redhat.com Signed-off-by: Alasdair G Kergon <agk@redhat.com>
-rw-r--r--drivers/md/dm-table.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index bc04518e9d8..81cbbf375bd 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1299,6 +1299,31 @@ static bool dm_table_discard_zeroes_data(struct dm_table *t)
return 1;
}
+static int device_is_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_is_nonrot(struct dm_table *t)
+{
+ struct dm_target *ti;
+ unsigned i = 0;
+
+ /* Ensure that all underlying device are non-rotational. */
+ while (i < dm_table_get_num_targets(t)) {
+ ti = dm_table_get_target(t, i++);
+
+ if (!ti->type->iterate_devices ||
+ !ti->type->iterate_devices(ti, device_is_nonrot, NULL))
+ return 0;
+ }
+
+ return 1;
+}
+
void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
struct queue_limits *limits)
{
@@ -1324,6 +1349,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
if (!dm_table_discard_zeroes_data(t))
q->limits.discard_zeroes_data = 0;
+ if (dm_table_is_nonrot(t))
+ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
+ else
+ queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
+
dm_table_set_integrity(t);
/*