[PATCH] storvsc: setup 1:1 mapping between hardware queue and CPU queue
STALE2601d
From: <hidden>
Date: 2019-08-19 19:35:46
Also in:
linux-scsi, lkml
Subsystem:
hyper-v/azure core and drivers, scsi subsystem, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, "James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
From: Long Li <longli@microsoft.com> storvsc doesn't use a dedicated hardware queue for a given CPU queue. When issuing I/O, it selects returning CPU (hardware queue) dynamically based on vmbus channel usage across all channels. This patch sets up a 1:1 mapping between hardware queue and CPU queue, thus avoiding unnecessary locking at upper layer when issuing I/O. Signed-off-by: Long Li <longli@microsoft.com> --- drivers/scsi/storvsc_drv.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index b89269120a2d..26c16d40ec46 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c@@ -1682,6 +1682,18 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) return 0; } +static int storvsc_map_queues(struct Scsi_Host *shost) +{ + unsigned int cpu; + struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT]; + + for_each_possible_cpu(cpu) { + qmap->mq_map[cpu] = cpu; + } + + return 0; +} + static struct scsi_host_template scsi_driver = { .module = THIS_MODULE, .name = "storvsc_host_t",
@@ -1697,6 +1709,7 @@ static struct scsi_host_template scsi_driver = { .this_id = -1, /* Make sure we dont get a sg segment crosses a page boundary */ .dma_boundary = PAGE_SIZE-1, + .map_queues = storvsc_map_queues, .no_write_same = 1, .track_queue_depth = 1, };
@@ -1836,8 +1849,7 @@ static int storvsc_probe(struct hv_device *device, /* * Set the number of HW queues we are supporting. */ - if (stor_device->num_sc != 0) - host->nr_hw_queues = stor_device->num_sc + 1; + host->nr_hw_queues = num_possible_cpus(); /* * Set the error handler work queue.
--
2.17.1