[SCSI] lpfc 8.2.8 v2 : Add sysfs control of target queue depth handling

Added new sysfs attribute lpfc_max_scsicmpl_time. Attribute, when enabled,
will control target queue depth based on I/O completion time.

Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

6 files changed, 85 insertions, 0 deletions

diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h
index 181538466117..3a500d683065 100644
--- a/drivers/scsi/lpfc/lpfc.h
+++ b/drivers/scsi/lpfc/lpfc.h
@@ -34,6 +34,11 @@ struct lpfc_sli2_slim;
 #define LPFC_IOCB_LIST_CNT      2250    /* list of IOCBs for fast-path usage. */
 #define LPFC_Q_RAMP_UP_INTERVAL 120     /* lun q_depth ramp up interval */
 #define LPFC_VNAME_LEN          100     /* vport symbolic name length */
+#define LPFC_TGTQ_INTERVAL      40000   /* Min amount of time between tgt
+                                           queue depth change in millisecs */
+#define LPFC_TGTQ_RAMPUP_PCENT  5       /* Target queue rampup in percentage */
+#define LPFC_MIN_TGT_QDEPTH     100
+#define LPFC_MAX_TGT_QDEPTH     0xFFFF
 
 /*
  * Following time intervals are used of adjusting SCSI device
@@ -363,6 +368,7 @@ struct lpfc_vport {
         uint32_t cfg_log_verbose;
         uint32_t cfg_max_luns;
         uint32_t cfg_enable_da_id;
+        uint32_t cfg_max_scsicmpl_time;
 
         uint32_t dev_loss_tmo_changed;
 
diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index 21397f37010d..343b0b36ed22 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -2297,6 +2297,48 @@ LPFC_VPORT_ATTR_RW(use_adisc, 0, 0, 1,
                    "Use ADISC on rediscovery to authenticate FCP devices");
 
 /*
+# lpfc_max_scsicmpl_time: Use scsi command completion time to control I/O queue
+# depth. Default value is 0. When the value of this parameter is zero the
+# SCSI command completion time is not used for controlling I/O queue depth. When
+# the parameter is set to a non-zero value, the I/O queue depth is controlled
+# to limit the I/O completion time to the parameter value.
+# The value is set in milliseconds.
+*/
+static int lpfc_max_scsicmpl_time;
+module_param(lpfc_max_scsicmpl_time, int, 0);
+MODULE_PARM_DESC(lpfc_max_scsicmpl_time,
+        "Use command completion time to control queue depth");
+lpfc_vport_param_show(max_scsicmpl_time);
+lpfc_vport_param_init(max_scsicmpl_time, 0, 0, 60000);
+static int
+lpfc_max_scsicmpl_time_set(struct lpfc_vport *vport, int val)
+{
+        struct Scsi_Host *shost = lpfc_shost_from_vport(vport);
+        struct lpfc_nodelist *ndlp, *next_ndlp;
+
+        if (val == vport->cfg_max_scsicmpl_time)
+                return 0;
+        if ((val < 0) || (val > 60000))
+                return -EINVAL;
+        vport->cfg_max_scsicmpl_time = val;
+
+        spin_lock_irq(shost->host_lock);
+        list_for_each_entry_safe(ndlp, next_ndlp, &vport->fc_nodes, nlp_listp) {
+                if (!NLP_CHK_NODE_ACT(ndlp))
+                        continue;
+                if (ndlp->nlp_state == NLP_STE_UNUSED_NODE)
+                        continue;
+                ndlp->cmd_qdepth = LPFC_MAX_TGT_QDEPTH;
+        }
+        spin_unlock_irq(shost->host_lock);
+        return 0;
+}
+lpfc_vport_param_store(max_scsicmpl_time);
+static DEVICE_ATTR(lpfc_max_scsicmpl_time, S_IRUGO | S_IWUSR,
+                   lpfc_max_scsicmpl_time_show,
+                   lpfc_max_scsicmpl_time_store);
+
+/*
 # lpfc_ack0: Use ACK0, instead of ACK1 for class 2 acknowledgement. Value
 # range is [0,1]. Default value is 0.
 */
@@ -2459,6 +2501,7 @@ struct device_attribute *lpfc_hba_attrs[] = {
         &dev_attr_lpfc_enable_hba_reset,
         &dev_attr_lpfc_enable_hba_heartbeat,
         &dev_attr_lpfc_sg_seg_cnt,
+        &dev_attr_lpfc_max_scsicmpl_time,
         NULL,
 };
 
@@ -3580,6 +3623,7 @@ lpfc_get_vport_cfgparam(struct lpfc_vport *vport)
         lpfc_restrict_login_init(vport, lpfc_restrict_login);
         lpfc_fcp_class_init(vport, lpfc_fcp_class);
         lpfc_use_adisc_init(vport, lpfc_use_adisc);
+        lpfc_max_scsicmpl_time_init(vport, lpfc_max_scsicmpl_time);
         lpfc_fdmi_on_init(vport, lpfc_fdmi_on);
         lpfc_discovery_threads_init(vport, lpfc_discovery_threads);
         lpfc_max_luns_init(vport, lpfc_max_luns);
diff --git a/drivers/scsi/lpfc/lpfc_disc.h b/drivers/scsi/lpfc/lpfc_disc.h
index 2db0b74b6fad..ccf8f41f345e 100644
--- a/drivers/scsi/lpfc/lpfc_disc.h
+++ b/drivers/scsi/lpfc/lpfc_disc.h
@@ -88,6 +88,9 @@ struct lpfc_nodelist {
         unsigned long last_ramp_up_time;        /* jiffy of last ramp up */
         unsigned long last_q_full_time;         /* jiffy of last queue full */
         struct kref     kref;
+        atomic_t cmd_pending;
+        uint32_t cmd_qdepth;
+        unsigned long last_change_time;
 };
 
 /* Defines for nlp_flag (uint32) */
diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index 3b00d9b86c7b..887a5283605f 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -2988,6 +2988,8 @@ lpfc_nlp_init(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
         INIT_LIST_HEAD(&ndlp->nlp_listp);
         kref_init(&ndlp->kref);
         NLP_INT_NODE_ACT(ndlp);
+        atomic_set(&ndlp->cmd_pending, 0);
+        ndlp->cmd_qdepth = LPFC_MAX_TGT_QDEPTH;
 
         lpfc_debugfs_disc_trc(vport, LPFC_DISC_TRC_NODE,
                 "node init:       did:x%x",
diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 72eef7e4a891..7b17f52660b4 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -628,6 +628,7 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
 
         lpfc_cmd->result = pIocbOut->iocb.un.ulpWord[4];
         lpfc_cmd->status = pIocbOut->iocb.ulpStatus;
+        atomic_dec(&pnode->cmd_pending);
 
         if (lpfc_cmd->status) {
                 if (lpfc_cmd->status == IOSTAT_LOCAL_REJECT &&
@@ -688,6 +689,29 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
 
         result = cmd->result;
         sdev = cmd->device;
+        if (vport->cfg_max_scsicmpl_time &&
+           time_after(jiffies, lpfc_cmd->start_time +
+                msecs_to_jiffies(vport->cfg_max_scsicmpl_time))) {
+                spin_lock_irqsave(sdev->host->host_lock, flags);
+                if ((pnode->cmd_qdepth > atomic_read(&pnode->cmd_pending) &&
+                    (atomic_read(&pnode->cmd_pending) > LPFC_MIN_TGT_QDEPTH) &&
+                    ((cmd->cmnd[0] == READ_10) || (cmd->cmnd[0] == WRITE_10))))
+                        pnode->cmd_qdepth = atomic_read(&pnode->cmd_pending);
+
+                pnode->last_change_time = jiffies;
+                spin_unlock_irqrestore(sdev->host->host_lock, flags);
+        } else if ((pnode->cmd_qdepth < LPFC_MAX_TGT_QDEPTH) &&
+                   time_after(jiffies, pnode->last_change_time +
+                        msecs_to_jiffies(LPFC_TGTQ_INTERVAL))) {
+                spin_lock_irqsave(sdev->host->host_lock, flags);
+                pnode->cmd_qdepth += pnode->cmd_qdepth *
+                        LPFC_TGTQ_RAMPUP_PCENT / 100;
+                if (pnode->cmd_qdepth > LPFC_MAX_TGT_QDEPTH)
+                        pnode->cmd_qdepth = LPFC_MAX_TGT_QDEPTH;
+                pnode->last_change_time = jiffies;
+                spin_unlock_irqrestore(sdev->host->host_lock, flags);
+        }
+
         lpfc_scsi_unprep_dma_buf(phba, lpfc_cmd);
         cmd->scsi_done(cmd);
 
@@ -1075,6 +1099,8 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
                 cmnd->result = ScsiResult(DID_TRANSPORT_DISRUPTED, 0);
                 goto out_fail_command;
         }
+        if (atomic_read(&ndlp->cmd_pending) >= ndlp->cmd_qdepth)
+                goto out_host_busy;
 
         lpfc_cmd = lpfc_get_scsi_buf(phba);
         if (lpfc_cmd == NULL) {
@@ -1093,6 +1119,7 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
         lpfc_cmd->pCmd  = cmnd;
         lpfc_cmd->rdata = rdata;
         lpfc_cmd->timeout = 0;
+        lpfc_cmd->start_time = jiffies;
         cmnd->host_scribble = (unsigned char *)lpfc_cmd;
         cmnd->scsi_done = done;
 
@@ -1102,6 +1129,7 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
 
         lpfc_scsi_prep_cmnd(vport, lpfc_cmd, ndlp);
 
+        atomic_inc(&ndlp->cmd_pending);
         err = lpfc_sli_issue_iocb(phba, &phba->sli.ring[psli->fcp_ring],
                                   &lpfc_cmd->cur_iocbq, SLI_IOCB_RET_IOCB);
         if (err)
@@ -1116,6 +1144,7 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
         return 0;
 
  out_host_busy_free_buf:
+        atomic_dec(&ndlp->cmd_pending);
         lpfc_scsi_unprep_dma_buf(phba, lpfc_cmd);
         lpfc_release_scsi_buf(phba, lpfc_cmd);
  out_host_busy:
diff --git a/drivers/scsi/lpfc/lpfc_scsi.h b/drivers/scsi/lpfc/lpfc_scsi.h
index daba92374985..6737cabe9a72 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.h
+++ b/drivers/scsi/lpfc/lpfc_scsi.h
@@ -139,6 +139,7 @@ struct lpfc_scsi_buf {
          */
         struct lpfc_iocbq cur_iocbq;
         wait_queue_head_t *waitq;
+        unsigned long start_time;
 };
 
 #define LPFC_SCSI_DMA_EXT_SIZE 264