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scsi: mpt3sas: Add support for shared host tagset for CPU hotplug
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MPT Fusion adapters can steer completions to individual queues and we now
have support for shared host-wide tags in the I/O stack. The addition of
the host-wide tags allows us to enable multiqueue support for MPT Fusion
adapters. Once host-wise tags are enabled, the CPU hotplug feature is also
supported.

Allow use of host-wide tags to be disabled through the "host_tagset_enable"
module parameter. Once we do not have any major performance regressions
using host-wide tags, we will drop the hand-crafted interrupt affinity
settings.

Performance is meeting expectations. About 3.1M IOPS using 24 Drive SSD on
Aero controllers.

Link: https://lore.kernel.org/r/20210202095832.23072-1-sreekanth.reddy@broadcom.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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@sreekanthbrcm @martinkpetersen
sreekanthbrcm authored and martinkpetersen committed Feb 9, 2021
1 parent d309ae0 commit 664f0dc
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Showing 3 changed files with 75 additions and 18 deletions.
50 changes: 33 additions & 17 deletions drivers/scsi/mpt3sas/mpt3sas_base.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3648,25 +3648,16 @@ _base_get_msix_index(struct MPT3SAS_ADAPTER *ioc,
base_mod64(atomic64_add_return(1,
&ioc->total_io_cnt), ioc->reply_queue_count) : 0;

return ioc->cpu_msix_table[raw_smp_processor_id()];
}
if (scmd && ioc->shost->nr_hw_queues > 1) {
u32 tag = blk_mq_unique_tag(scmd->request);

/**
* _base_sdev_nr_inflight_request -get number of inflight requests
* of a request queue.
* @q: request_queue object
*
* returns number of inflight request of a request queue.
*/
inline unsigned long
_base_sdev_nr_inflight_request(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[0];
return blk_mq_unique_tag_to_hwq(tag) +
ioc->high_iops_queues;
}

return atomic_read(&hctx->nr_active);
return ioc->cpu_msix_table[raw_smp_processor_id()];
}


/**
* _base_get_high_iops_msix_index - get the msix index of
* high iops queues
Expand All @@ -3686,7 +3677,8 @@ _base_get_high_iops_msix_index(struct MPT3SAS_ADAPTER *ioc,
* reply queues in terms of batch count 16 when outstanding
* IOs on the target device is >=8.
*/
if (_base_sdev_nr_inflight_request(scmd->device->request_queue) >

if (atomic_read(&scmd->device->device_busy) >
MPT3SAS_DEVICE_HIGH_IOPS_DEPTH)
return base_mod64((
atomic64_add_return(1, &ioc->high_iops_outstanding) /
Expand Down Expand Up @@ -3739,8 +3731,23 @@ mpt3sas_base_get_smid_scsiio(struct MPT3SAS_ADAPTER *ioc, u8 cb_idx,
struct scsi_cmnd *scmd)
{
struct scsiio_tracker *request = scsi_cmd_priv(scmd);
unsigned int tag = scmd->request->tag;
u16 smid;
u32 tag, unique_tag;

unique_tag = blk_mq_unique_tag(scmd->request);
tag = blk_mq_unique_tag_to_tag(unique_tag);

/*
* Store hw queue number corresponding to the tag.
* This hw queue number is used later to determine
* the unique_tag using the logic below. This unique_tag
* is used to retrieve the scmd pointer corresponding
* to tag using scsi_host_find_tag() API.
*
* tag = smid - 1;
* unique_tag = ioc->io_queue_num[tag] << BLK_MQ_UNIQUE_TAG_BITS | tag;
*/
ioc->io_queue_num[tag] = blk_mq_unique_tag_to_hwq(unique_tag);

smid = tag + 1;
request->cb_idx = cb_idx;
Expand Down Expand Up @@ -3831,6 +3838,7 @@ mpt3sas_base_free_smid(struct MPT3SAS_ADAPTER *ioc, u16 smid)

mpt3sas_base_clear_st(ioc, st);
_base_recovery_check(ioc);
ioc->io_queue_num[smid - 1] = 0;
return;
}

Expand Down Expand Up @@ -5362,6 +5370,9 @@ _base_release_memory_pools(struct MPT3SAS_ADAPTER *ioc)
kfree(ioc->chain_lookup);
ioc->chain_lookup = NULL;
}

kfree(ioc->io_queue_num);
ioc->io_queue_num = NULL;
}

/**
Expand Down Expand Up @@ -5773,6 +5784,11 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc)
ioc_info(ioc, "internal(0x%p): depth(%d), start smid(%d)\n",
ioc->internal,
ioc->internal_depth, ioc->internal_smid));

ioc->io_queue_num = kcalloc(ioc->scsiio_depth,
sizeof(u16), GFP_KERNEL);
if (!ioc->io_queue_num)
goto out;
/*
* The number of NVMe page sized blocks needed is:
* (((sg_tablesize * 8) - 1) / (page_size - 8)) + 1
Expand Down
1 change: 1 addition & 0 deletions drivers/scsi/mpt3sas/mpt3sas_base.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1439,6 +1439,7 @@ struct MPT3SAS_ADAPTER {
spinlock_t scsi_lookup_lock;
int pending_io_count;
wait_queue_head_t reset_wq;
u16 *io_queue_num;

/* PCIe SGL */
struct dma_pool *pcie_sgl_dma_pool;
Expand Down
42 changes: 41 additions & 1 deletion drivers/scsi/mpt3sas/mpt3sas_scsih.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@
#include <linux/interrupt.h>
#include <linux/aer.h>
#include <linux/raid_class.h>
#include <linux/blk-mq-pci.h>
#include <asm/unaligned.h>

#include "mpt3sas_base.h"
Expand Down Expand Up @@ -168,6 +169,11 @@ MODULE_PARM_DESC(multipath_on_hba,
"\t SAS 2.0 & SAS 3.0 HBA - This will be disabled,\n\t\t"
"\t SAS 3.5 HBA - This will be enabled)");

static int host_tagset_enable = 1;
module_param(host_tagset_enable, int, 0444);
MODULE_PARM_DESC(host_tagset_enable,
"Shared host tagset enable/disable Default: enable(1)");

/* raid transport support */
static struct raid_template *mpt3sas_raid_template;
static struct raid_template *mpt2sas_raid_template;
Expand Down Expand Up @@ -1743,10 +1749,12 @@ mpt3sas_scsih_scsi_lookup_get(struct MPT3SAS_ADAPTER *ioc, u16 smid)
struct scsi_cmnd *scmd = NULL;
struct scsiio_tracker *st;
Mpi25SCSIIORequest_t *mpi_request;
u16 tag = smid - 1;

if (smid > 0 &&
smid <= ioc->scsiio_depth - INTERNAL_SCSIIO_CMDS_COUNT) {
u32 unique_tag = smid - 1;
u32 unique_tag =
ioc->io_queue_num[tag] << BLK_MQ_UNIQUE_TAG_BITS | tag;

mpi_request = mpt3sas_base_get_msg_frame(ioc, smid);

Expand Down Expand Up @@ -11599,6 +11607,22 @@ scsih_scan_finished(struct Scsi_Host *shost, unsigned long time)
return 1;
}

/**
* scsih_map_queues - map reply queues with request queues
* @shost: SCSI host pointer
*/
static int scsih_map_queues(struct Scsi_Host *shost)
{
struct MPT3SAS_ADAPTER *ioc =
(struct MPT3SAS_ADAPTER *)shost->hostdata;

if (ioc->shost->nr_hw_queues == 1)
return 0;

return blk_mq_pci_map_queues(&shost->tag_set.map[HCTX_TYPE_DEFAULT],
ioc->pdev, ioc->high_iops_queues);
}

/* shost template for SAS 2.0 HBA devices */
static struct scsi_host_template mpt2sas_driver_template = {
.module = THIS_MODULE,
Expand Down Expand Up @@ -11666,6 +11690,7 @@ static struct scsi_host_template mpt3sas_driver_template = {
.sdev_attrs = mpt3sas_dev_attrs,
.track_queue_depth = 1,
.cmd_size = sizeof(struct scsiio_tracker),
.map_queues = scsih_map_queues,
};

/* raid transport support for SAS 3.0 HBA devices */
Expand Down Expand Up @@ -12028,6 +12053,21 @@ _scsih_probe(struct pci_dev *pdev, const struct pci_device_id *id)
} else
ioc->hide_drives = 0;

shost->host_tagset = 0;
shost->nr_hw_queues = 1;

if (ioc->is_gen35_ioc && ioc->reply_queue_count > 1 &&
host_tagset_enable && ioc->smp_affinity_enable) {

shost->host_tagset = 1;
shost->nr_hw_queues =
ioc->reply_queue_count - ioc->high_iops_queues;

dev_info(&ioc->pdev->dev,
"Max SCSIIO MPT commands: %d shared with nr_hw_queues = %d\n",
shost->can_queue, shost->nr_hw_queues);
}

rv = scsi_add_host(shost, &pdev->dev);
if (rv) {
ioc_err(ioc, "failure at %s:%d/%s()!\n",
Expand Down

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