[PATCHv2 3/3] mpt3sas: scsi-mq interrupt steering

Hannes Reinecke
2017-02-17T08:26:04Z

The device has several reply queues, so this patch implements
correct scsi-mq interrupt steering to take advantage of full
blk-mq support.
However, as performance results are inconclusive this patch
also adds a module parameter 'use_blk_mq' to enable full
mq support; the parameter itself is off by default.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/mpt3sas/mpt3sas_base.c | 22 +++++++++++++++++-----
drivers/scsi/mpt3sas/mpt3sas_scsih.c | 27 ++++++++++++++++++++++++++-
2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 96adf84..10102de 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -865,12 +865,15 @@ static int mpt3sas_remove_dead_ioc_func(void *arg)
struct scsiio_tracker *
mpt3sas_get_st_from_smid(struct MPT3SAS_ADAPTER *ioc, u16 smid)
{
+ u16 hwq, tag;
u32 unique_tag;
struct scsi_cmnd *cmd;

WARN_ON(!smid);
WARN_ON(smid >= ioc->hi_priority_smid);
- unique_tag = smid - 1;
+ hwq = (smid - 1) % ioc->shost->nr_hw_queues;
+ tag = (smid - 1) / ioc->shost->nr_hw_queues;
+ unique_tag = blk_mq_make_unique_tag(hwq, tag);
cmd = scsi_host_find_tag(ioc->shost, unique_tag);
if (cmd)
return scsi_cmd_priv(cmd);
@@ -2347,6 +2350,7 @@ struct scsiio_tracker *
{
struct scsiio_tracker *request;
u16 smid;
+ u16 hwq = 0;

if (!scmd) {
smid = 1;
@@ -2356,11 +2360,15 @@ struct scsiio_tracker *
u16 tag = blk_mq_unique_tag_to_tag(unique_tag);

WARN_ON(tag < ioc->shost->reserved_cmds);
+ hwq = blk_mq_unique_tag_to_hwq(unique_tag);
+ smid = (tag * ioc->shost->nr_hw_queues) + hwq + 1;
request = scsi_cmd_priv(scmd);
- smid = tag + 1;
}
request->cb_idx = cb_idx;
- request->msix_io = mpt3sas_base_get_msix_index(ioc);
+ if (scmd && ioc->shost->nr_hw_queues > 1)
+ request->msix_io = hwq;
+ else
+ request->msix_io = mpt3sas_base_get_msix_index(ioc);
request->smid = smid;
INIT_LIST_HEAD(&request->chain_list);
return request->smid;
@@ -3527,9 +3535,13 @@ void mpt3sas_base_clear_st(struct MPT3SAS_ADAPTER *ioc,
*/
ioc->shost->reserved_cmds = INTERNAL_SCSIIO_CMDS_COUNT;
ioc->shost->can_queue = ioc->scsiio_depth - ioc->shost->reserved_cmds;
+ if (ioc->shost->nr_hw_queues > 1) {
+ ioc->shost->nr_hw_queues = ioc->reply_queue_count;
+ ioc->shost->can_queue /= ioc->reply_queue_count;
+ }
dinitprintk(ioc, pr_info(MPT3SAS_FMT
- "scsi host: can_queue depth (%d)\n",
- ioc->name, ioc->shost->can_queue));
+ "scsi host: can_queue depth (%d), nr_hw_queues (%d)\n",
+ ioc->name, ioc->shost->can_queue, ioc->shost->nr_hw_queues));

/* contiguous pool for request and chains, 16 byte align, one extra "
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 77ab449..c68d7a7 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -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"
@@ -147,6 +148,11 @@ static int _scsih_add_device(struct MPT3SAS_ADAPTER *ioc, u16 handle,
module_param(prot_mask, int, 0);
MODULE_PARM_DESC(prot_mask, " host protection capabilities mask, def=7 ");

+static int use_blk_mq;
+module_param(use_blk_mq, int, S_IRUGO);
+MODULE_PARM_DESC(use_blk_mq,
+ "Enable scsi-mq (single queue=0/all queues=1/default=0)");
+
/* raid transport support */
struct raid_template *mpt3sas_raid_template;
struct raid_template *mpt2sas_raid_template;
@@ -1072,7 +1078,9 @@ struct _sas_node *
_scsih_scsi_lookup_get_clear(struct MPT3SAS_ADAPTER *ioc, u16 smid)
{
if (smid > 0) {
- u32 unique_tag = smid - 1;
+ u16 hwq = (smid - 1) % ioc->shost->nr_hw_queues;
+ u16 tag = (smid - 1) / ioc->shost->nr_hw_queues;
+ u32 unique_tag = blk_mq_make_unique_tag(hwq, tag);

return scsi_host_find_tag(ioc->shost, unique_tag);
}
@@ -4150,6 +4158,11 @@ void _flush_running(struct request *req, void *data, bool reserved)
if (raid_device && raid_device->direct_io_enabled)
mpt3sas_setup_direct_io(ioc, scmd, raid_device, mpi_request);

+ if (shost_use_blk_mq(ioc->shost) && (ioc->shost->nr_hw_queues > 1)) {
+ u32 unique_tag = blk_mq_unique_tag(scmd->request);
+
+ msix_task = blk_mq_unique_tag_to_hwq(unique_tag);
+ }
if (likely(mpi_request->Function == MPI2_FUNCTION_SCSI_IO_REQUEST)) {
if (sas_target_priv_data->flags & MPT_TARGET_FASTPATH_IO) {
mpi_request->IoFlags = cpu_to_le16(scmd->cmd_len |
@@ -8545,6 +8558,16 @@ static void sas_device_make_active(struct MPT3SAS_ADAPTER *ioc,
return 1;
}

+static int scsih_map_queues(struct Scsi_Host *shost)
+{
+ struct MPT3SAS_ADAPTER *ioc = shost_priv(shost);
+
+ if (shost->nr_hw_queues > 1)
+ return blk_mq_pci_map_queues(&shost->tag_set, ioc->pdev);
+
+ return -EINVAL;
+}
+
/* shost template for SAS 2.0 HBA devices */
static struct scsi_host_template mpt2sas_driver_template = {
.module = THIS_MODULE,
@@ -8558,6 +8581,7 @@ static void sas_device_make_active(struct MPT3SAS_ADAPTER *ioc,
.slave_destroy = scsih_slave_destroy,
.scan_finished = scsih_scan_finished,
.scan_start = scsih_scan_start,
+ .map_queues = scsih_map_queues,
.change_queue_depth = scsih_change_queue_depth,
.eh_abort_handler = scsih_abort,
.eh_device_reset_handler = scsih_dev_reset,
@@ -8825,6 +8849,7 @@ static void sas_device_make_active(struct MPT3SAS_ADAPTER *ioc,
shost->transportt = mpt3sas_transport_template;
shost->unique_id = ioc->id;
shost->use_blk_mq = 1;
+ shost->nr_hw_queues = use_blk_mq ? num_online_cpus() : 1;

if (max_sectors != 0xFFFF) {
if (max_sectors < 64) {
--
1.8.5.6