From 4a84067dbfce436b81779e585bf712b02ceee552 Mon Sep 17 00:00:00 2001 From: Vasu Dev Date: Thu, 22 Oct 2009 15:46:33 -0700 Subject: [SCSI] add queue_depth ramp up code Current FC HBA queue_depth ramp up code depends on last queue full time. The sdev already has last_queue_full_time field to track last queue full time but stored value is truncated by last four bits. So this patch updates last_queue_full_time without truncating last 4 bits to store full value and then updates its only current usages in scsi_track_queue_full to ignore last four bits to keep current usages same while also use this field in added ramp up code. Adds scsi_handle_queue_ramp_up to ramp up queue_depth on successful completion of IO. The scsi_handle_queue_ramp_up will do ramp up on all luns of a target, just same as ramp down done on all luns on a target. The ramp up is skipped in case the change_queue_depth is not supported by LLD or already reached to added max_queue_depth. Updates added max_queue_depth on every new update to default queue_depth value. The ramp up is also skipped if lapsed time since either last queue ramp up or down is less than LLD specified queue_ramp_up_period. Adds queue_ramp_up_period to sysfs but only if change_queue_depth is supported since ramp up and queue_ramp_up_period is needed only in case change_queue_depth is supported first. Initializes queue_ramp_up_period to 120HZ jiffies as initial default value, it is same as used in existing lpfc and qla2xxx. -v2 Combined all ramp code into this single patch. -v3 Moves max_queue_depth initialization after slave_configure is called from after slave_alloc calling done. Also adjusted max_queue_depth check to skip ramp up if current queue_depth is >= max_queue_depth. -v4 Changes sdev->queue_ramp_up_period unit to ms when using sysfs i/f to store or show its value. Signed-off-by: Vasu Dev Tested-by: Christof Schmitt Tested-by: Giridhar Malavali Signed-off-by: James Bottomley --- drivers/scsi/scsi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'drivers/scsi/scsi.c') diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index dd098cad337b..a60da5555577 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -940,10 +940,16 @@ EXPORT_SYMBOL(scsi_adjust_queue_depth); */ int scsi_track_queue_full(struct scsi_device *sdev, int depth) { - if ((jiffies >> 4) == sdev->last_queue_full_time) + + /* + * Don't let QUEUE_FULLs on the same + * jiffies count, they could all be from + * same event. + */ + if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4)) return 0; - sdev->last_queue_full_time = (jiffies >> 4); + sdev->last_queue_full_time = jiffies; if (sdev->last_queue_full_depth != depth) { sdev->last_queue_full_count = 1; sdev->last_queue_full_depth = depth; -- cgit v1.2.3