diff options
| author | James Smart <jsmart2021@gmail.com> | 2019-08-15 19:36:49 -0700 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2019-08-19 22:14:10 -0400 |
| commit | 77ffd3465ba837e9dc714e17b014e77b2eae765a (patch) | |
| tree | e7600f3b593e0dc5019efb7b013cd15785319d6c /drivers/scsi/lpfc/lpfc_sli4.h | |
| parent | 7c7cfdcf7f1777c7376fc9a239980de04b6b5ea1 (diff) | |
scsi: lpfc: Mitigate high memory pre-allocation by SCSI-MQ
When SCSI-MQ is enabled, the SCSI-MQ layers will do pre-allocation of MQ
resources based on shost values set by the driver. In newer cases of the
driver, which attempts to set nr_hw_queues to the cpu count, the
multipliers become excessive, with a single shost having SCSI-MQ
pre-allocation reaching into the multiple GBytes range. NPIV, which
creates additional shosts, only multiply this overhead. On lower-memory
systems, this can exhaust system memory very quickly, resulting in a system
crash or failures in the driver or elsewhere due to low memory conditions.
After testing several scenarios, the situation can be mitigated by limiting
the value set in shost->nr_hw_queues to 4. Although the shost values were
changed, the driver still had per-cpu hardware queues of its own that
allowed parallelization per-cpu. Testing revealed that even with the
smallish number for nr_hw_queues for SCSI-MQ, performance levels remained
near maximum with the within-driver affiinitization.
A module parameter was created to allow the value set for the nr_hw_queues
to be tunable.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/lpfc/lpfc_sli4.h')
| -rw-r--r-- | drivers/scsi/lpfc/lpfc_sli4.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/scsi/lpfc/lpfc_sli4.h b/drivers/scsi/lpfc/lpfc_sli4.h index 3aeca387b22a..329f7aa7e169 100644 --- a/drivers/scsi/lpfc/lpfc_sli4.h +++ b/drivers/scsi/lpfc/lpfc_sli4.h @@ -44,6 +44,11 @@ #define LPFC_HBA_HDWQ_MAX 128 #define LPFC_HBA_HDWQ_DEF 0 +/* FCP MQ queue count limiting */ +#define LPFC_FCP_MQ_THRESHOLD_MIN 0 +#define LPFC_FCP_MQ_THRESHOLD_MAX 128 +#define LPFC_FCP_MQ_THRESHOLD_DEF 8 + /* Common buffer size to accomidate SCSI and NVME IO buffers */ #define LPFC_COMMON_IO_BUF_SZ 768 |