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| 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_init.c | |
| parent | scsi: ufs: Fix NULL pointer dereference in ufshcd_config_vreg_hpm() (diff) | |
| download | linux-dev-77ffd3465ba837e9dc714e17b014e77b2eae765a.tar.xz linux-dev-77ffd3465ba837e9dc714e17b014e77b2eae765a.zip | |
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 '')
| -rw-r--r-- | drivers/scsi/lpfc/lpfc_init.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c index a7549ae32542..1ac98becb5ba 100644 --- a/drivers/scsi/lpfc/lpfc_init.c +++ b/drivers/scsi/lpfc/lpfc_init.c @@ -4309,10 +4309,12 @@ lpfc_create_port(struct lpfc_hba *phba, int instance, struct device *dev) shost->max_cmd_len = 16; if (phba->sli_rev == LPFC_SLI_REV4) { - if (phba->cfg_fcp_io_sched == LPFC_FCP_SCHED_BY_HDWQ) - shost->nr_hw_queues = phba->cfg_hdw_queue; - else - shost->nr_hw_queues = phba->sli4_hba.num_present_cpu; + if (!phba->cfg_fcp_mq_threshold || + phba->cfg_fcp_mq_threshold > phba->cfg_hdw_queue) + phba->cfg_fcp_mq_threshold = phba->cfg_hdw_queue; + + shost->nr_hw_queues = min_t(int, 2 * num_possible_nodes(), + phba->cfg_fcp_mq_threshold); shost->dma_boundary = phba->sli4_hba.pc_sli4_params.sge_supp_len-1; |