[SCSI] lpfc 8.1.1 : Add polled-mode support
- Add functionality to run in polled mode only. Includes run time
attribute to enable mode.
- Enable runtime writable hba settings for coallescing and delay parameters
Customers have requested a mode in the driver to run strictly polled.
This is generally to support an environment where the server is extremely
loaded and is looking to reclaim some cpu cycles from adapter interrupt
handling.
This patch adds a new "poll" attribute, and the following behavior:
if value is 0 (default):
The driver uses the normal method for i/o completion. It uses the
firmware feature of interrupt coalesing. The firmware allows a
minimum number of i/o completions before an interrupt, or a maximum
time delay between interrupts. By default, the driver sets these
to no delay (disabled) or 1 i/o - meaning coalescing is disabled.
Attributes were provided to change the coalescing values, but it was
a module-load time only and global across all adapters.
This patch allows them to be writable on a per-adapter basis.
if value is 1 :
Interrupts are left enabled, expecting that the user has tuned the
interrupt coalescing values. When this setting is enabled, the driver
will attempt to service completed i/o whenever new i/o is submitted
to the adapter. If the coalescing values are large, and the i/o
generation rate steady, an interrupt will be avoided by servicing
completed i/o prior to the coalescing thresholds kicking in. However,
if the i/o completion load is high enough or i/o generation slow, the
coalescion values will ensure that completed i/o is serviced in a timely
fashion.
if value is 3 :
Turns off FCP i/o interrupts altogether. The coalescing values now have
no effect. A new attribute "poll_tmo" (default 10ms) exists to set
the polling interval for i/o completion. When this setting is enabled,
the driver will attempt to service completed i/o and restart the
interval timer whenever new i/o is submitted. This behavior allows for
servicing of completed i/o sooner than the interval timer, but ensures
that if no i/o is being issued, then the interval timer will kick in
to service the outstanding i/o.
Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 7dc7810..c422220 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -151,18 +151,22 @@
}
struct lpfc_scsi_buf*
-lpfc_sli_get_scsi_buf(struct lpfc_hba * phba)
+lpfc_get_scsi_buf(struct lpfc_hba * phba)
{
struct lpfc_scsi_buf * lpfc_cmd = NULL;
struct list_head *scsi_buf_list = &phba->lpfc_scsi_buf_list;
+ unsigned long iflag = 0;
+ spin_lock_irqsave(&phba->scsi_buf_list_lock, iflag);
list_remove_head(scsi_buf_list, lpfc_cmd, struct lpfc_scsi_buf, list);
+ spin_unlock_irqrestore(&phba->scsi_buf_list_lock, iflag);
return lpfc_cmd;
}
static void
lpfc_release_scsi_buf(struct lpfc_hba * phba, struct lpfc_scsi_buf * psb)
{
+ unsigned long iflag = 0;
/*
* There are only two special cases to consider. (1) the scsi command
* requested scatter-gather usage or (2) the scsi command allocated
@@ -180,8 +184,10 @@
}
}
+ spin_lock_irqsave(&phba->scsi_buf_list_lock, iflag);
psb->pCmd = NULL;
list_add_tail(&psb->list, &phba->lpfc_scsi_buf_list);
+ spin_unlock_irqrestore(&phba->scsi_buf_list_lock, iflag);
}
static int
@@ -403,7 +409,6 @@
struct lpfc_rport_data *rdata = lpfc_cmd->rdata;
struct lpfc_nodelist *pnode = rdata->pnode;
struct scsi_cmnd *cmd = lpfc_cmd->pCmd;
- unsigned long iflag;
lpfc_cmd->result = pIocbOut->iocb.un.ulpWord[4];
lpfc_cmd->status = pIocbOut->iocb.ulpStatus;
@@ -457,9 +462,7 @@
cmd->scsi_done(cmd);
- spin_lock_irqsave(phba->host->host_lock, iflag);
lpfc_release_scsi_buf(phba, lpfc_cmd);
- spin_unlock_irqrestore(phba->host->host_lock, iflag);
}
static void
@@ -707,6 +710,37 @@
return lpfcinfobuf;
}
+static __inline__ void lpfc_poll_rearm_timer(struct lpfc_hba * phba)
+{
+ unsigned long poll_tmo_expires =
+ (jiffies + msecs_to_jiffies(phba->cfg_poll_tmo));
+
+ if (phba->sli.ring[LPFC_FCP_RING].txcmplq_cnt)
+ mod_timer(&phba->fcp_poll_timer,
+ poll_tmo_expires);
+}
+
+void lpfc_poll_start_timer(struct lpfc_hba * phba)
+{
+ lpfc_poll_rearm_timer(phba);
+}
+
+void lpfc_poll_timeout(unsigned long ptr)
+{
+ struct lpfc_hba *phba = (struct lpfc_hba *)ptr;
+ unsigned long iflag;
+
+ spin_lock_irqsave(phba->host->host_lock, iflag);
+
+ if (phba->cfg_poll & ENABLE_FCP_RING_POLLING) {
+ lpfc_sli_poll_fcp_ring (phba);
+ if (phba->cfg_poll & DISABLE_FCP_RING_INT)
+ lpfc_poll_rearm_timer(phba);
+ }
+
+ spin_unlock_irqrestore(phba->host->host_lock, iflag);
+}
+
static int
lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
{
@@ -733,7 +767,7 @@
cmnd->result = ScsiResult(DID_BUS_BUSY, 0);
goto out_fail_command;
}
- lpfc_cmd = lpfc_sli_get_scsi_buf (phba);
+ lpfc_cmd = lpfc_get_scsi_buf (phba);
if (lpfc_cmd == NULL) {
lpfc_printf_log(phba, KERN_INFO, LOG_FCP,
"%d:0707 driver's buffer pool is empty, "
@@ -761,11 +795,17 @@
&lpfc_cmd->cur_iocbq, SLI_IOCB_RET_IOCB);
if (err)
goto out_host_busy_free_buf;
+
+ if (phba->cfg_poll & ENABLE_FCP_RING_POLLING) {
+ lpfc_sli_poll_fcp_ring(phba);
+ if (phba->cfg_poll & DISABLE_FCP_RING_INT)
+ lpfc_poll_rearm_timer(phba);
+ }
+
return 0;
out_host_busy_free_buf:
lpfc_release_scsi_buf(phba, lpfc_cmd);
- cmnd->host_scribble = NULL;
out_host_busy:
return SCSI_MLQUEUE_HOST_BUSY;
@@ -839,9 +879,15 @@
goto out;
}
+ if (phba->cfg_poll & DISABLE_FCP_RING_INT)
+ lpfc_sli_poll_fcp_ring (phba);
+
/* Wait for abort to complete */
while (lpfc_cmd->pCmd == cmnd)
{
+ if (phba->cfg_poll & DISABLE_FCP_RING_INT)
+ lpfc_sli_poll_fcp_ring (phba);
+
spin_unlock_irq(phba->host->host_lock);
schedule_timeout_uninterruptible(LPFC_ABORT_WAIT*HZ);
spin_lock_irq(phba->host->host_lock);
@@ -905,7 +951,7 @@
break;
}
- lpfc_cmd = lpfc_sli_get_scsi_buf (phba);
+ lpfc_cmd = lpfc_get_scsi_buf (phba);
if (lpfc_cmd == NULL)
goto out;
@@ -1001,7 +1047,7 @@
lpfc_block_requests(phba);
spin_lock_irq(shost->host_lock);
- lpfc_cmd = lpfc_sli_get_scsi_buf (phba);
+ lpfc_cmd = lpfc_get_scsi_buf(phba);
if (lpfc_cmd == NULL)
goto out;
@@ -1136,10 +1182,10 @@
break;
}
- spin_lock_irqsave(phba->host->host_lock, flags);
+ spin_lock_irqsave(&phba->scsi_buf_list_lock, flags);
phba->total_scsi_bufs++;
list_add_tail(&scsi_buf->list, &phba->lpfc_scsi_buf_list);
- spin_unlock_irqrestore(phba->host->host_lock, flags);
+ spin_unlock_irqrestore(&phba->scsi_buf_list_lock, flags);
}
return 0;
}
@@ -1163,6 +1209,12 @@
*/
rport->dev_loss_tmo = phba->cfg_nodev_tmo + 5;
+ if (phba->cfg_poll & ENABLE_FCP_RING_POLLING) {
+ lpfc_sli_poll_fcp_ring(phba);
+ if (phba->cfg_poll & DISABLE_FCP_RING_INT)
+ lpfc_poll_rearm_timer(phba);
+ }
+
return 0;
}