Commit 4a84067d authored by Vasu Dev's avatar Vasu Dev Committed by James Bottomley

[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

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.

 Combined all ramp code into this single patch.

 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.

 Changes sdev->queue_ramp_up_period unit to ms when using sysfs i/f
to store or show its value.
Signed-off-by: default avatarVasu Dev <>
Tested-by: default avatarChristof Schmitt <>
Tested-by: default avatarGiridhar Malavali <>
Signed-off-by: default avatarJames Bottomley <>
parent 14caf44c
......@@ -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;
......@@ -331,6 +331,42 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
struct scsi_host_template *sht = sdev->host->hostt;
struct scsi_device *tmp_sdev;
if (!sht->change_queue_depth ||
sdev->queue_depth >= sdev->max_queue_depth)
if (time_before(jiffies,
sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
if (time_before(jiffies,
sdev->last_queue_full_time + sdev->queue_ramp_up_period))
* Walk all devices of a target and do
* ramp up on them.
shost_for_each_device(tmp_sdev, sdev->host) {
if (tmp_sdev->channel != sdev->channel ||
tmp_sdev->id != sdev->id ||
tmp_sdev->queue_depth == sdev->max_queue_depth)
* call back into LLD to increase queue_depth by one
* with ramp up reason code.
sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
sdev->last_queue_ramp_up = jiffies;
static void scsi_handle_queue_full(struct scsi_device *sdev)
struct scsi_host_template *sht = sdev->host->hostt;
......@@ -393,6 +429,7 @@ static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
switch (status_byte(scmd->result)) {
case GOOD:
return SUCCESS;
......@@ -1425,6 +1462,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
case GOOD:
return SUCCESS;
......@@ -251,6 +251,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
sdev->model = scsi_null_device_strs;
sdev->rev = scsi_null_device_strs;
sdev->host = shost;
sdev->queue_ramp_up_period = SCSI_DEFAULT_RAMP_UP_PERIOD;
sdev->id = starget->id;
sdev->lun = lun;
sdev->channel = starget->channel;
......@@ -941,6 +942,8 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
sdev->max_queue_depth = sdev->queue_depth;
* Ok, the device is now all set up, we can
* register it and tell the rest of the kernel
......@@ -771,6 +771,8 @@ sdev_store_queue_depth_rw(struct device *dev, struct device_attribute *attr,
if (retval < 0)
return retval;
sdev->max_queue_depth = sdev->queue_depth;
return count;
......@@ -778,6 +780,37 @@ static struct device_attribute sdev_attr_queue_depth_rw =
__ATTR(queue_depth, S_IRUGO | S_IWUSR, sdev_show_queue_depth,
static ssize_t
sdev_show_queue_ramp_up_period(struct device *dev,
struct device_attribute *attr,
char *buf)
struct scsi_device *sdev;
sdev = to_scsi_device(dev);
return snprintf(buf, 20, "%u\n",
static ssize_t
sdev_store_queue_ramp_up_period(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
struct scsi_device *sdev = to_scsi_device(dev);
unsigned long period;
if (strict_strtoul(buf, 10, &period))
return -EINVAL;
sdev->queue_ramp_up_period = msecs_to_jiffies(period);
return period;
static struct device_attribute sdev_attr_queue_ramp_up_period =
__ATTR(queue_ramp_up_period, S_IRUGO | S_IWUSR,
static ssize_t
sdev_store_queue_type_rw(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
......@@ -866,8 +899,12 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
/* create queue files, which may be writable, depending on the host */
if (sdev->host->hostt->change_queue_depth)
error = device_create_file(&sdev->sdev_gendev, &sdev_attr_queue_depth_rw);
if (sdev->host->hostt->change_queue_depth) {
error = device_create_file(&sdev->sdev_gendev,
error = device_create_file(&sdev->sdev_gendev,
error = device_create_file(&sdev->sdev_gendev, &dev_attr_queue_depth);
if (error) {
......@@ -81,11 +81,14 @@ struct scsi_device {
struct list_head starved_entry;
struct scsi_cmnd *current_cmnd; /* currently active command */
unsigned short queue_depth; /* How deep of a queue we want */
unsigned short max_queue_depth; /* max queue depth */
unsigned short last_queue_full_depth; /* These two are used by */
unsigned short last_queue_full_count; /* scsi_track_queue_full() */
unsigned long last_queue_full_time;/* don't let QUEUE_FULLs on the same
jiffie count on our counter, they
could all be from the same event. */
unsigned long last_queue_full_time; /* last queue full time */
unsigned long queue_ramp_up_period; /* ramp up period in jiffies */
unsigned long last_queue_ramp_up; /* last queue ramp up time */
unsigned int id, lun, channel;
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