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scsi: lpfc: Update lpfc_ramp_down_queue_handler() logic 

[ Upstream commit bb01163143 ]

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>
This commit is contained in:
Justin Tee 2024-03-05 12:04:55 -08:00 committed by Greg Kroah-Hartman
parent 01cd1b7b68
commit b241595d3d
2 changed files with 4 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/scsi/lpfc/lpfc.h
View File

@ -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

13
drivers/scsi/lpfc/lpfc_scsi.c
View File

@ -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);
}
/**