diff options
| author |   James Smart <jsmart2021@gmail.com> | 2018-09-10 10:30:49 -0700 |
|---|---|---|
| committer |   Martin K. Petersen <martin.petersen@oracle.com> | 2018-09-11 20:37:33 -0400 |
| commit | 18027a8ccca5b9189f49be0d8b84dbc717084a26 (patch) | |
| tree | aa4dbf9ac409f149884c6df5b1d2a1950f7e427b | |
| parent | scsi: lpfc: Fix errors in log messages. (diff) | |
| download | linux-dev-18027a8ccca5b9189f49be0d8b84dbc717084a26.tar.xz linux-dev-18027a8ccca5b9189f49be0d8b84dbc717084a26.zip | |
scsi: lpfc: reduce locking when updating statistics
Currently, on each io completion, the stats update routine indiscriminately
holds a lock. While holding the adapter-wide lock, checks are made to check
whether status are being tracked. When disabled (the default), the locking
wasted a lot of cycles.
Check for stats enablement before taking the lock.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/scsi/lpfc/lpfc_scsi.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c index 549eb58ee6d9..4fa6703a9ec9 100644 --- a/drivers/scsi/lpfc/lpfc_scsi.c +++ b/drivers/scsi/lpfc/lpfc_scsi.c @@ -202,8 +202,8 @@ lpfc_sli4_set_rsp_sgl_last(struct lpfc_hba *phba, static void lpfc_update_stats(struct lpfc_hba *phba, struct lpfc_scsi_buf *lpfc_cmd) { - struct lpfc_rport_data *rdata = lpfc_cmd->rdata; - struct lpfc_nodelist *pnode = rdata->pnode; + struct lpfc_rport_data *rdata; + struct lpfc_nodelist *pnode; struct scsi_cmnd *cmd = lpfc_cmd->pCmd; unsigned long flags; struct Scsi_Host *shost = cmd->device->host; @@ -211,17 +211,19 @@ lpfc_update_stats(struct lpfc_hba *phba, struct lpfc_scsi_buf *lpfc_cmd) unsigned long latency; int i; - if (cmd->result) + if (!vport->stat_data_enabled || + vport->stat_data_blocked || + (cmd->result)) return; latency = jiffies_to_msecs((long)jiffies - (long)lpfc_cmd->start_time); + rdata = lpfc_cmd->rdata; + pnode = rdata->pnode; spin_lock_irqsave(shost->host_lock, flags); - if (!vport->stat_data_enabled || - vport->stat_data_blocked || - !pnode || - !pnode->lat_data || - (phba->bucket_type == LPFC_NO_BUCKET)) { + if (!pnode || + !pnode->lat_data || + (phba->bucket_type == LPFC_NO_BUCKET)) { spin_unlock_irqrestore(shost->host_lock, flags); return; } |