Re: [PATCH 09/11] megaraid_sas: switch fusion adapters to MQ

[Sumit Saxena <sumit.saxena@broadcom.com>]

On Mon, Dec 2, 2019 at 9:09 PM Hannes Reinecke <hare@suse.de> wrote:
>
> Fusion adapters can steer completions to individual queues, and
> we now have support for shared host-wide tags.
> So we can enable multiqueue support for fusion adapters and
> drop the hand-crafted interrupt affinity settings.

Hi Hannes,

Ming Lei also proposed similar changes in megaraid_sas driver some
time back and it had resulted in performance drop-
https://patchwork.kernel.org/patch/10969511/

So, we will do some performance tests with this patch and update you.

Thanks,
Sumit
>
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
>  drivers/scsi/megaraid/megaraid_sas.h        |  1 -
>  drivers/scsi/megaraid/megaraid_sas_base.c   | 65 +++++++++--------------------
>  drivers/scsi/megaraid/megaraid_sas_fusion.c | 14 ++++---
>  3 files changed, 28 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
> index bd8184072bed..844ea2d6dbb8 100644
> --- a/drivers/scsi/megaraid/megaraid_sas.h
> +++ b/drivers/scsi/megaraid/megaraid_sas.h
> @@ -2261,7 +2261,6 @@ enum MR_PERF_MODE {
>
>  struct megasas_instance {
>
> -       unsigned int *reply_map;
>         __le32 *producer;
>         dma_addr_t producer_h;
>         __le32 *consumer;
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
> index a4bc81479284..9d0d74e3d491 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -37,6 +37,7 @@
>  #include <linux/poll.h>
>  #include <linux/vmalloc.h>
>  #include <linux/irq_poll.h>
> +#include <linux/blk-mq-pci.h>
>
>  #include <scsi/scsi.h>
>  #include <scsi/scsi_cmnd.h>
> @@ -3106,6 +3107,19 @@ megasas_bios_param(struct scsi_device *sdev, struct block_device *bdev,
>         return 0;
>  }
>
> +static int megasas_map_queues(struct Scsi_Host *shost)
> +{
> +       struct megasas_instance *instance;
> +
> +       instance = (struct megasas_instance *)shost->hostdata;
> +
> +       if (!instance->smp_affinity_enable)
> +               return 0;
> +
> +       return blk_mq_pci_map_queues(&shost->tag_set.map[HCTX_TYPE_DEFAULT],
> +                       instance->pdev, instance->low_latency_index_start);
> +}
> +
>  static void megasas_aen_polling(struct work_struct *work);
>
>  /**
> @@ -3414,9 +3428,11 @@ static struct scsi_host_template megasas_template = {
>         .eh_timed_out = megasas_reset_timer,
>         .shost_attrs = megaraid_host_attrs,
>         .bios_param = megasas_bios_param,
> +       .map_queues = megasas_map_queues,
>         .change_queue_depth = scsi_change_queue_depth,
>         .max_segment_size = 0xffffffff,
>         .no_write_same = 1,
> +       .host_tagset = 1,
>  };
>
>  /**
> @@ -5695,34 +5711,6 @@ megasas_setup_jbod_map(struct megasas_instance *instance)
>                 instance->use_seqnum_jbod_fp = false;
>  }
>
> -static void megasas_setup_reply_map(struct megasas_instance *instance)
> -{
> -       const struct cpumask *mask;
> -       unsigned int queue, cpu, low_latency_index_start;
> -
> -       low_latency_index_start = instance->low_latency_index_start;
> -
> -       for (queue = low_latency_index_start; queue < instance->msix_vectors; queue++) {
> -               mask = pci_irq_get_affinity(instance->pdev, queue);
> -               if (!mask)
> -                       goto fallback;
> -
> -               for_each_cpu(cpu, mask)
> -                       instance->reply_map[cpu] = queue;
> -       }
> -       return;
> -
> -fallback:
> -       queue = low_latency_index_start;
> -       for_each_possible_cpu(cpu) {
> -               instance->reply_map[cpu] = queue;
> -               if (queue == (instance->msix_vectors - 1))
> -                       queue = low_latency_index_start;
> -               else
> -                       queue++;
> -       }
> -}
> -
>  /**
>   * megasas_get_device_list -   Get the PD and LD device list from FW.
>   * @instance:                  Adapter soft state
> @@ -6021,12 +6009,6 @@ static int megasas_init_fw(struct megasas_instance *instance)
>                                         instance->is_rdpq = (scratch_pad_1 & MR_RDPQ_MODE_OFFSET) ?
>                                                                 1 : 0;
>
> -                               if (instance->adapter_type >= INVADER_SERIES &&
> -                                   !instance->msix_combined) {
> -                                       instance->msix_load_balance = true;
> -                                       instance->smp_affinity_enable = false;
> -                               }
> -
>                                 /* Save 1-15 reply post index address to local memory
>                                  * Index 0 is already saved from reg offset
>                                  * MPI2_REPLY_POST_HOST_INDEX_OFFSET
> @@ -6145,8 +6127,6 @@ static int megasas_init_fw(struct megasas_instance *instance)
>                         goto fail_init_adapter;
>         }
>
> -       megasas_setup_reply_map(instance);
> -
>         dev_info(&instance->pdev->dev,
>                 "current msix/online cpus\t: (%d/%d)\n",
>                 instance->msix_vectors, (unsigned int)num_online_cpus());
> @@ -6780,6 +6760,9 @@ static int megasas_io_attach(struct megasas_instance *instance)
>         host->max_id = MEGASAS_MAX_DEV_PER_CHANNEL;
>         host->max_lun = MEGASAS_MAX_LUN;
>         host->max_cmd_len = 16;
> +       if (instance->adapter_type != MFI_SERIES && instance->msix_vectors > 0)
> +               host->nr_hw_queues = instance->msix_vectors -
> +                       instance->low_latency_index_start;
>
>         /*
>          * Notify the mid-layer about the new controller
> @@ -6947,11 +6930,6 @@ static inline int megasas_alloc_mfi_ctrl_mem(struct megasas_instance *instance)
>   */
>  static int megasas_alloc_ctrl_mem(struct megasas_instance *instance)
>  {
> -       instance->reply_map = kcalloc(nr_cpu_ids, sizeof(unsigned int),
> -                                     GFP_KERNEL);
> -       if (!instance->reply_map)
> -               return -ENOMEM;
> -
>         switch (instance->adapter_type) {
>         case MFI_SERIES:
>                 if (megasas_alloc_mfi_ctrl_mem(instance))
> @@ -6968,8 +6946,6 @@ static int megasas_alloc_ctrl_mem(struct megasas_instance *instance)
>
>         return 0;
>   fail:
> -       kfree(instance->reply_map);
> -       instance->reply_map = NULL;
>         return -ENOMEM;
>  }
>
> @@ -6982,7 +6958,6 @@ static int megasas_alloc_ctrl_mem(struct megasas_instance *instance)
>   */
>  static inline void megasas_free_ctrl_mem(struct megasas_instance *instance)
>  {
> -       kfree(instance->reply_map);
>         if (instance->adapter_type == MFI_SERIES) {
>                 if (instance->producer)
>                         dma_free_coherent(&instance->pdev->dev, sizeof(u32),
> @@ -7645,8 +7620,6 @@ megasas_resume(struct pci_dev *pdev)
>         if (rval < 0)
>                 goto fail_reenable_msix;
>
> -       megasas_setup_reply_map(instance);
> -
>         if (instance->adapter_type != MFI_SERIES) {
>                 megasas_reset_reply_desc(instance);
>                 if (megasas_ioc_init_fusion(instance)) {
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> index e301458bcbae..bae96b82bb10 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> @@ -2731,6 +2731,7 @@ megasas_build_ldio_fusion(struct megasas_instance *instance,
>         struct MR_PRIV_DEVICE *mrdev_priv;
>         struct RAID_CONTEXT *rctx;
>         struct RAID_CONTEXT_G35 *rctx_g35;
> +       u32 tag = blk_mq_unique_tag(scp->request);
>
>         device_id = MEGASAS_DEV_INDEX(scp);
>
> @@ -2837,7 +2838,7 @@ megasas_build_ldio_fusion(struct megasas_instance *instance,
>                                     instance->msix_vectors));
>         else
>                 cmd->request_desc->SCSIIO.MSIxIndex =
> -                       instance->reply_map[raw_smp_processor_id()];
> +                       blk_mq_unique_tag_to_hwq(tag);
>
>         if (instance->adapter_type >= VENTURA_SERIES) {
>                 /* FP for Optimal raid level 1.
> @@ -3080,6 +3081,7 @@ megasas_build_syspd_fusion(struct megasas_instance *instance,
>         u16 pd_index = 0;
>         u16 os_timeout_value;
>         u16 timeout_limit;
> +       u32 tag = blk_mq_unique_tag(scmd->request);
>         struct MR_DRV_RAID_MAP_ALL *local_map_ptr;
>         struct RAID_CONTEXT     *pRAID_Context;
>         struct MR_PD_CFG_SEQ_NUM_SYNC *pd_sync;
> @@ -3169,7 +3171,7 @@ megasas_build_syspd_fusion(struct megasas_instance *instance,
>                                     instance->msix_vectors));
>         else
>                 cmd->request_desc->SCSIIO.MSIxIndex =
> -                       instance->reply_map[raw_smp_processor_id()];
> +                       blk_mq_unique_tag_to_hwq(tag);
>
>         if (!fp_possible) {
>                 /* system pd firmware path */
> @@ -3373,7 +3375,7 @@ megasas_build_and_issue_cmd_fusion(struct megasas_instance *instance,
>  {
>         struct megasas_cmd_fusion *cmd, *r1_cmd = NULL;
>         union MEGASAS_REQUEST_DESCRIPTOR_UNION *req_desc;
> -       u32 index;
> +       u32 index, blk_tag, unique_tag;
>
>         if ((megasas_cmd_type(scmd) == READ_WRITE_LDIO) &&
>                 instance->ldio_threshold &&
> @@ -3389,7 +3391,9 @@ megasas_build_and_issue_cmd_fusion(struct megasas_instance *instance,
>                 return SCSI_MLQUEUE_HOST_BUSY;
>         }
>
> -       cmd = megasas_get_cmd_fusion(instance, scmd->request->tag);
> +       unique_tag = blk_mq_unique_tag(scmd->request);
> +       blk_tag = blk_mq_unique_tag_to_tag(unique_tag);
> +       cmd = megasas_get_cmd_fusion(instance, blk_tag);
>
>         if (!cmd) {
>                 atomic_dec(&instance->fw_outstanding);
> @@ -3430,7 +3434,7 @@ megasas_build_and_issue_cmd_fusion(struct megasas_instance *instance,
>          */
>         if (cmd->r1_alt_dev_handle != MR_DEVHANDLE_INVALID) {
>                 r1_cmd = megasas_get_cmd_fusion(instance,
> -                               (scmd->request->tag + instance->max_fw_cmds));
> +                               (blk_tag + instance->max_fw_cmds));
>                 megasas_prepare_secondRaid1_IO(instance, cmd, r1_cmd);
>         }
>
> --
> 2.16.4
>