scsi: lpfc: Adapt partitioned XRI lists to efficient sharing

The XRI get/put lists were partitioned per hardware queue. However, the
adapter rarely had sufficient resources to give a large number of resources
per queue. As such, it became common for a cpu to encounter a lack of XRI
resource and request the upper io stack to retry after returning a BUSY
condition. This occurred even though other cpus were idle and not using
their resources.

Create as efficient a scheme as possible to move resources to the cpus that
need them. Each cpu maintains a small private pool which it allocates from
for io. There is a watermark that the cpu attempts to keep in the private
pool.  The private pool, when empty, pulls from a global pool from the
cpu. When the cpu's global pool is empty it will pull from other cpu's
global pool. As there many cpu global pools (1 per cpu or hardware queue
count) and as each cpu selects what cpu to pull from at different rates and
at different times, it creates a radomizing effect that minimizes the
number of cpu's that will contend with each other when the steal XRI's from
another cpu's global pool.

On io completion, a cpu will push the XRI back on to its private pool.  A
watermark level is maintained for the private pool such that when it is
exceeded it will move XRI's to the CPU global pool so that other cpu's may
allocate them.

On NVME, as heartbeat commands are critical to get placed on the wire, a
single expedite pool is maintained. When a heartbeat is to be sent, it will
allocate an XRI from the expedite pool rather than the normal cpu
private/global pools. On any io completion, if a reduction in the expedite
pools is seen, it will be replenished before the XRI is placed on the cpu
private pool.

Statistics are added to aid understanding the XRI levels on each cpu and
their behaviors.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/scsi/lpfc/lpfc_crtn.h b/drivers/scsi/lpfc/lpfc_crtn.h
index 1bd1362f39a0..726cd6a7c452 100644
--- a/drivers/scsi/lpfc/lpfc_crtn.h
+++ b/drivers/scsi/lpfc/lpfc_crtn.h
@@ -521,6 +521,7 @@ int lpfc_sli4_io_sgl_update(struct lpfc_hba *phba);
 int lpfc_sli4_post_io_sgl_list(struct lpfc_hba *phba,
 		struct list_head *blist, int xricnt);
 int lpfc_new_io_buf(struct lpfc_hba *phba, int num_to_alloc);
+void lpfc_io_free(struct lpfc_hba *phba);
 void lpfc_free_sgl_list(struct lpfc_hba *, struct list_head *);
 uint32_t lpfc_sli_port_speed_get(struct lpfc_hba *);
 int lpfc_sli4_request_firmware_update(struct lpfc_hba *, uint8_t);
@@ -573,6 +574,21 @@ void lpfc_nvme_mod_param_dep(struct lpfc_hba *phba);
 void lpfc_nvme_abort_fcreq_cmpl(struct lpfc_hba *phba,
 				struct lpfc_iocbq *cmdiocb,
 				struct lpfc_wcqe_complete *abts_cmpl);
+void lpfc_create_multixri_pools(struct lpfc_hba *phba);
+void lpfc_create_destroy_pools(struct lpfc_hba *phba);
+void lpfc_move_xri_pvt_to_pbl(struct lpfc_hba *phba, u32 hwqid);
+void lpfc_move_xri_pbl_to_pvt(struct lpfc_hba *phba, u32 hwqid, u32 cnt);
+void lpfc_adjust_high_watermark(struct lpfc_hba *phba, u32 hwqid);
+void lpfc_keep_pvt_pool_above_lowwm(struct lpfc_hba *phba, u32 hwqid);
+void lpfc_adjust_pvt_pool_count(struct lpfc_hba *phba, u32 hwqid);
+#ifdef LPFC_MXP_STAT
+void lpfc_snapshot_mxp(struct lpfc_hba *, u32);
+#endif
+struct lpfc_io_buf *lpfc_get_io_buf(struct lpfc_hba *phba,
+				struct lpfc_nodelist *ndlp, u32 hwqid,
+				int);
+void lpfc_release_io_buf(struct lpfc_hba *phba, struct lpfc_io_buf *ncmd,
+			 struct lpfc_sli4_hdw_queue *qp);
 void lpfc_nvme_cmd_template(void);
 void lpfc_nvmet_cmd_template(void);
 extern int lpfc_enable_nvmet_cnt;