> On Sep 2, 2020, at 2:25 AM, Nilesh Javali <njavali@xxxxxxxxxxx> wrote:
>
> From: Quinn Tran <qutran@xxxxxxxxxxx>
>
> This patch tracks number of IOCB resources used in the IO
> fast path. If the number of used IOCBs reach a high water
> limit, driver would return the IO as busy and let upper layer
> retry. This prevents over subscription of IOCB resources where
> any future error recovery command is unable to cut through.
> Enable IOCB throttling by default.
>
> Signed-off-by: Quinn Tran <qutran@xxxxxxxxxxx>
> Signed-off-by: Arun Easi <aeasi@xxxxxxxxxxx>
> Signed-off-by: Nilesh Javali <njavali@xxxxxxxxxxx>
> ---
> drivers/scsi/qla2xxx/qla_def.h | 17 ++++++++++
> drivers/scsi/qla2xxx/qla_dfs.c | 14 ++++++++
> drivers/scsi/qla2xxx/qla_gbl.h | 3 ++
> drivers/scsi/qla2xxx/qla_init.c | 26 +++++++++++++++
> drivers/scsi/qla2xxx/qla_inline.h | 55 +++++++++++++++++++++++++++++++
> drivers/scsi/qla2xxx/qla_iocb.c | 28 ++++++++++++++++
> drivers/scsi/qla2xxx/qla_isr.c | 2 ++
> drivers/scsi/qla2xxx/qla_os.c | 6 ++++
> 8 files changed, 151 insertions(+)
>
> diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
> index 3ca8665638c4..863b9c7766e1 100644
> --- a/drivers/scsi/qla2xxx/qla_def.h
> +++ b/drivers/scsi/qla2xxx/qla_def.h
> @@ -624,6 +624,12 @@ enum {
> TYPE_TGT_TMCMD, /* task management */
> };
>
> +struct iocb_resource {
> + u8 res_type;
> + u8 pad;
> + u16 iocb_cnt;
> +};
> +
> typedef struct srb {
> /*
> * Do not move cmd_type field, it needs to
> @@ -631,6 +637,7 @@ typedef struct srb {
> */
> uint8_t cmd_type;
> uint8_t pad[3];
> + struct iocb_resource iores;
> struct kref cmd_kref; /* need to migrate ref_count over to this */
> void *priv;
> wait_queue_head_t nvme_ls_waitq;
> @@ -3577,6 +3584,15 @@ struct req_que {
> uint8_t req_pkt[REQUEST_ENTRY_SIZE];
> };
>
> +struct qla_fw_resources {
> + u16 iocbs_total;
> + u16 iocbs_limit;
> + u16 iocbs_qp_limit;
> + u16 iocbs_used;
> +};
> +
> +#define QLA_IOCB_PCT_LIMIT 95
> +
> /*Queue pair data structure */
> struct qla_qpair {
> spinlock_t qp_lock;
> @@ -3629,6 +3645,7 @@ struct qla_qpair {
> uint64_t retry_term_jiff;
> struct qla_tgt_counters tgt_counters;
> uint16_t cpuid;
> + struct qla_fw_resources fwres ____cacheline_aligned;
> };
>
> /* Place holder for FW buffer parameters */
> diff --git a/drivers/scsi/qla2xxx/qla_dfs.c b/drivers/scsi/qla2xxx/qla_dfs.c
> index 118f2b223531..6f5f18fc974a 100644
> --- a/drivers/scsi/qla2xxx/qla_dfs.c
> +++ b/drivers/scsi/qla2xxx/qla_dfs.c
> @@ -261,6 +261,8 @@ qla_dfs_fw_resource_cnt_show(struct seq_file *s, void *unused)
> struct scsi_qla_host *vha = s->private;
> uint16_t mb[MAX_IOCB_MB_REG];
> int rc;
> + struct qla_hw_data *ha = vha->hw;
> + u16 iocbs_used, i;
>
> rc = qla24xx_res_count_wait(vha, mb, SIZEOF_IOCB_MB_REG);
> if (rc != QLA_SUCCESS) {
> @@ -285,6 +287,18 @@ qla_dfs_fw_resource_cnt_show(struct seq_file *s, void *unused)
> mb[23]);
> }
>
> + if (ql2xenforce_iocb_limit) {
> + /* lock is not require. It's an estimate. */
> + iocbs_used = ha->base_qpair->fwres.iocbs_used;
> + for (i = 0; i < ha->max_qpairs; i++) {
> + if (ha->queue_pair_map[i])
> + iocbs_used += ha->queue_pair_map[i]->fwres.iocbs_used;
> + }
> +
> + seq_printf(s, "Driver: estimate iocb used [%d] high water limit [%d]\n",
> + iocbs_used, ha->base_qpair->fwres.iocbs_limit);
> + }
> +
> return 0;
> }
>
> diff --git a/drivers/scsi/qla2xxx/qla_gbl.h b/drivers/scsi/qla2xxx/qla_gbl.h
> index 3360857c4405..9c4d077edf9e 100644
> --- a/drivers/scsi/qla2xxx/qla_gbl.h
> +++ b/drivers/scsi/qla2xxx/qla_gbl.h
> @@ -129,6 +129,8 @@ int qla2x00_reserve_mgmt_server_loop_id(scsi_qla_host_t *);
> void qla_rscn_replay(fc_port_t *fcport);
> void qla24xx_free_purex_item(struct purex_item *item);
> extern bool qla24xx_risc_firmware_invalid(uint32_t *);
> +void qla_init_iocb_limit(scsi_qla_host_t *);
> +
>
> /*
> * Global Data in qla_os.c source file.
> @@ -175,6 +177,7 @@ extern int qla2xuseresexchforels;
> extern int ql2xexlogins;
> extern int ql2xdifbundlinginternalbuffers;
> extern int ql2xfulldump_on_mpifail;
> +extern int ql2xenforce_iocb_limit;
>
> extern int qla2x00_loop_reset(scsi_qla_host_t *);
> extern void qla2x00_abort_all_cmds(scsi_qla_host_t *, int);
> diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
> index 99f322fb74ab..a1603bad3ee6 100644
> --- a/drivers/scsi/qla2xxx/qla_init.c
> +++ b/drivers/scsi/qla2xxx/qla_init.c
> @@ -3622,6 +3622,31 @@ qla24xx_detect_sfp(scsi_qla_host_t *vha)
> return ha->flags.lr_detected;
> }
>
> +void qla_init_iocb_limit(scsi_qla_host_t *vha)
> +{
> + u16 i, num_qps;
> + u32 limit;
> + struct qla_hw_data *ha = vha->hw;
> +
> + num_qps = ha->num_qpairs + 1;
> + limit = (ha->orig_fw_iocb_count * QLA_IOCB_PCT_LIMIT) / 100;
> +
> + ha->base_qpair->fwres.iocbs_total = ha->orig_fw_iocb_count;
> + ha->base_qpair->fwres.iocbs_limit = limit;
> + ha->base_qpair->fwres.iocbs_qp_limit = limit / num_qps;
> + ha->base_qpair->fwres.iocbs_used = 0;
> + for (i = 0; i < ha->max_qpairs; i++) {
> + if (ha->queue_pair_map[i]) {
> + ha->queue_pair_map[i]->fwres.iocbs_total =
> + ha->orig_fw_iocb_count;
> + ha->queue_pair_map[i]->fwres.iocbs_limit = limit;
> + ha->queue_pair_map[i]->fwres.iocbs_qp_limit =
> + limit / num_qps;
> + ha->queue_pair_map[i]->fwres.iocbs_used = 0;
> + }
> + }
> +}
> +
> /**
> * qla2x00_setup_chip() - Load and start RISC firmware.
> * @vha: HA context
> @@ -3722,6 +3747,7 @@ qla2x00_setup_chip(scsi_qla_host_t *vha)
> MIN_MULTI_ID_FABRIC - 1;
> }
> qla2x00_get_resource_cnts(vha);
> + qla_init_iocb_limit(vha);
>
> /*
> * Allocate the array of outstanding commands
> diff --git a/drivers/scsi/qla2xxx/qla_inline.h b/drivers/scsi/qla2xxx/qla_inline.h
> index 5501b4c581ec..9e9a5d3fb802 100644
> --- a/drivers/scsi/qla2xxx/qla_inline.h
> +++ b/drivers/scsi/qla2xxx/qla_inline.h
> @@ -373,3 +373,58 @@ qla2xxx_get_fc4_priority(struct scsi_qla_host *vha)
>
> return (data >> 6) & BIT_0 ? FC4_PRIORITY_FCP : FC4_PRIORITY_NVME;
> }
> +
> +enum {
> + RESOURCE_NONE,
> + RESOURCE_INI,
> +};
> +
> +static inline int
> +qla_get_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
> +{
> + u16 iocbs_used, i;
> + struct qla_hw_data *ha = qp->vha->hw;
> +
> + if (!ql2xenforce_iocb_limit) {
> + iores->res_type = RESOURCE_NONE;
> + return 0;
> + }
> +
> + if ((iores->iocb_cnt + qp->fwres.iocbs_used) < qp->fwres.iocbs_qp_limit) {
> + qp->fwres.iocbs_used += iores->iocb_cnt;
> + return 0;
> + } else {
> + /* no need to acquire qpair lock. It's just rough calculation */
> + iocbs_used = ha->base_qpair->fwres.iocbs_used;
> + for (i = 0; i < ha->max_qpairs; i++) {
> + if (ha->queue_pair_map[i])
> + iocbs_used += ha->queue_pair_map[i]->fwres.iocbs_used;
> + }
> +
> + if ((iores->iocb_cnt + iocbs_used) < qp->fwres.iocbs_limit) {
> + qp->fwres.iocbs_used += iores->iocb_cnt;
> + return 0;
> + } else {
> + iores->res_type = RESOURCE_NONE;
> + return -ENOSPC;
> + }
> + }
> +}
> +
> +static inline void
> +qla_put_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
> +{
> + switch (iores->res_type) {
> + case RESOURCE_NONE:
> + break;
> + default:
> + if (qp->fwres.iocbs_used >= iores->iocb_cnt) {
> + qp->fwres.iocbs_used -= iores->iocb_cnt;
> + } else {
> + // should not happen
> + qp->fwres.iocbs_used = 0;
> + }
> + break;
> + }
> + iores->res_type = RESOURCE_NONE;
> +}
> diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
> index d69e16e844aa..b60a332e5846 100644
> --- a/drivers/scsi/qla2xxx/qla_iocb.c
> +++ b/drivers/scsi/qla2xxx/qla_iocb.c
> @@ -1637,6 +1637,12 @@ qla24xx_start_scsi(srb_t *sp)
>
> tot_dsds = nseg;
> req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> +
> + sp->iores.res_type = RESOURCE_INI;
> + sp->iores.iocb_cnt = req_cnt;
> + if (qla_get_iocbs(sp->qpair, &sp->iores))
> + goto queuing_error;
> +
> if (req->cnt < (req_cnt + 2)) {
> cnt = IS_SHADOW_REG_CAPABLE(ha) ? *req->out_ptr :
> rd_reg_dword_relaxed(req->req_q_out);
> @@ -1709,6 +1715,7 @@ qla24xx_start_scsi(srb_t *sp)
> if (tot_dsds)
> scsi_dma_unmap(cmd);
>
> + qla_put_iocbs(sp->qpair, &sp->iores);
> spin_unlock_irqrestore(&ha->hardware_lock, flags);
>
> return QLA_FUNCTION_FAILED;
> @@ -1822,6 +1829,12 @@ qla24xx_dif_start_scsi(srb_t *sp)
> /* Total Data and protection sg segment(s) */
> tot_prot_dsds = nseg;
> tot_dsds += nseg;
> +
> + sp->iores.res_type = RESOURCE_INI;
> + sp->iores.iocb_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> + if (qla_get_iocbs(sp->qpair, &sp->iores))
> + goto queuing_error;
> +
> if (req->cnt < (req_cnt + 2)) {
> cnt = IS_SHADOW_REG_CAPABLE(ha) ? *req->out_ptr :
> rd_reg_dword_relaxed(req->req_q_out);
> @@ -1896,6 +1909,7 @@ qla24xx_dif_start_scsi(srb_t *sp)
> }
> /* Cleanup will be performed by the caller (queuecommand) */
>
> + qla_put_iocbs(sp->qpair, &sp->iores);
> spin_unlock_irqrestore(&ha->hardware_lock, flags);
> return QLA_FUNCTION_FAILED;
> }
> @@ -1957,6 +1971,12 @@ qla2xxx_start_scsi_mq(srb_t *sp)
>
> tot_dsds = nseg;
> req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> +
> + sp->iores.res_type = RESOURCE_INI;
> + sp->iores.iocb_cnt = req_cnt;
> + if (qla_get_iocbs(sp->qpair, &sp->iores))
> + goto queuing_error;
> +
> if (req->cnt < (req_cnt + 2)) {
> cnt = IS_SHADOW_REG_CAPABLE(ha) ? *req->out_ptr :
> rd_reg_dword_relaxed(req->req_q_out);
> @@ -2029,6 +2049,7 @@ qla2xxx_start_scsi_mq(srb_t *sp)
> if (tot_dsds)
> scsi_dma_unmap(cmd);
>
> + qla_put_iocbs(sp->qpair, &sp->iores);
> spin_unlock_irqrestore(&qpair->qp_lock, flags);
>
> return QLA_FUNCTION_FAILED;
> @@ -2157,6 +2178,12 @@ qla2xxx_dif_start_scsi_mq(srb_t *sp)
> /* Total Data and protection sg segment(s) */
> tot_prot_dsds = nseg;
> tot_dsds += nseg;
> +
> + sp->iores.res_type = RESOURCE_INI;
> + sp->iores.iocb_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> + if (qla_get_iocbs(sp->qpair, &sp->iores))
> + goto queuing_error;
> +
> if (req->cnt < (req_cnt + 2)) {
> cnt = IS_SHADOW_REG_CAPABLE(ha) ? *req->out_ptr :
> rd_reg_dword_relaxed(req->req_q_out);
> @@ -2234,6 +2261,7 @@ qla2xxx_dif_start_scsi_mq(srb_t *sp)
> }
> /* Cleanup will be performed by the caller (queuecommand) */
>
> + qla_put_iocbs(sp->qpair, &sp->iores);
> spin_unlock_irqrestore(&qpair->qp_lock, flags);
> return QLA_FUNCTION_FAILED;
> }
> diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
> index a63f2000fadf..bb3beaa77d39 100644
> --- a/drivers/scsi/qla2xxx/qla_isr.c
> +++ b/drivers/scsi/qla2xxx/qla_isr.c
> @@ -2901,6 +2901,7 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
> }
> return;
> }
> + qla_put_iocbs(sp->qpair, &sp->iores);
>
> if (sp->cmd_type != TYPE_SRB) {
> req->outstanding_cmds[handle] = NULL;
> @@ -3313,6 +3314,7 @@ qla2x00_error_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, sts_entry_t *pkt)
> default:
> sp = qla2x00_get_sp_from_handle(vha, func, req, pkt);
> if (sp) {
> + qla_put_iocbs(sp->qpair, &sp->iores);
> sp->done(sp, res);
> return 0;
> }
> diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
> index c53cc31cd068..a4d737b92ec1 100644
> --- a/drivers/scsi/qla2xxx/qla_os.c
> +++ b/drivers/scsi/qla2xxx/qla_os.c
> @@ -40,6 +40,11 @@ module_param(ql2xfulldump_on_mpifail, int, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(ql2xfulldump_on_mpifail,
> "Set this to take full dump on MPI hang.");
>
> +int ql2xenforce_iocb_limit = 1;
> +module_param(ql2xenforce_iocb_limit, int, S_IRUGO | S_IWUSR);
> +MODULE_PARM_DESC(ql2xenforce_iocb_limit,
> + "Enforce IOCB throttling, to avoid FW congestion. (default: 0)");
> +
> /*
> * CT6 CTX allocation cache
> */
> @@ -3316,6 +3321,7 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
> for (i = 0; i < ha->max_qpairs; i++)
> qla2xxx_create_qpair(base_vha, 5, 0, startit);
> }
> + qla_init_iocb_limit(base_vha);
>
> if (ha->flags.running_gold_fw)
> goto skip_dpc;
> --
> 2.19.0.rc0
>
Looks Good.
Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
--
Himanshu Madhani Oracle Linux Engineering
