4.19-stable review patch. If anyone has any objections, please let me know.
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From: Justin Tee justin.tee@broadcom.com
[ Upstream commit bb011631435c705cdeddca68d5c85fd40a4320f9 ]
Typically when an out of resource CQE status is detected, the lpfc_ramp_down_queue_handler() logic is called to help reduce I/O load by reducing an sdev's queue_depth.
However, the current lpfc_rampdown_queue_depth() logic does not help reduce queue_depth. num_cmd_success is never updated and is always zero, which means new_queue_depth will always be set to sdev->queue_depth. So, new_queue_depth = sdev->queue_depth - new_queue_depth always sets new_queue_depth to zero. And, scsi_change_queue_depth(sdev, 0) is essentially a no-op.
Change the lpfc_ramp_down_queue_handler() logic to set new_queue_depth equal to sdev->queue_depth subtracted from number of times num_rsrc_err was incremented. If num_rsrc_err is >= sdev->queue_depth, then set new_queue_depth equal to 1. Eventually, the frequency of Good_Status frames will signal SCSI upper layer to auto increase the queue_depth back to the driver default of 64 via scsi_handle_queue_ramp_up().
Signed-off-by: Justin Tee justin.tee@broadcom.com Link: https://lore.kernel.org/r/20240305200503.57317-5-justintee8345@gmail.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/lpfc/lpfc.h | 1 - drivers/scsi/lpfc/lpfc_scsi.c | 13 ++++--------- 2 files changed, 4 insertions(+), 10 deletions(-)
diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h index 53b661793268f..5698928d8029c 100644 --- a/drivers/scsi/lpfc/lpfc.h +++ b/drivers/scsi/lpfc/lpfc.h @@ -989,7 +989,6 @@ struct lpfc_hba { unsigned long bit_flags; #define FABRIC_COMANDS_BLOCKED 0 atomic_t num_rsrc_err; - atomic_t num_cmd_success; unsigned long last_rsrc_error_time; unsigned long last_ramp_down_time; #ifdef CONFIG_SCSI_LPFC_DEBUG_FS diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c index 425b83618a2e5..02d067e1fc45c 100644 --- a/drivers/scsi/lpfc/lpfc_scsi.c +++ b/drivers/scsi/lpfc/lpfc_scsi.c @@ -303,11 +303,10 @@ lpfc_ramp_down_queue_handler(struct lpfc_hba *phba) struct Scsi_Host *shost; struct scsi_device *sdev; unsigned long new_queue_depth; - unsigned long num_rsrc_err, num_cmd_success; + unsigned long num_rsrc_err; int i;
num_rsrc_err = atomic_read(&phba->num_rsrc_err); - num_cmd_success = atomic_read(&phba->num_cmd_success);
/* * The error and success command counters are global per @@ -322,20 +321,16 @@ lpfc_ramp_down_queue_handler(struct lpfc_hba *phba) for (i = 0; i <= phba->max_vports && vports[i] != NULL; i++) { shost = lpfc_shost_from_vport(vports[i]); shost_for_each_device(sdev, shost) { - new_queue_depth = - sdev->queue_depth * num_rsrc_err / - (num_rsrc_err + num_cmd_success); - if (!new_queue_depth) - new_queue_depth = sdev->queue_depth - 1; + if (num_rsrc_err >= sdev->queue_depth) + new_queue_depth = 1; else new_queue_depth = sdev->queue_depth - - new_queue_depth; + num_rsrc_err; scsi_change_queue_depth(sdev, new_queue_depth); } } lpfc_destroy_vport_work_array(phba, vports); atomic_set(&phba->num_rsrc_err, 0); - atomic_set(&phba->num_cmd_success, 0); }
/**