Commit 0ed88102 authored Sep 06, 2019 by Long Li Committed by Martin K. Petersen Sep 23, 2019

scsi: storvsc: setup 1:1 mapping between hardware queue and CPU queue

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 advertises num_present_cpus() as number of hardware queues. This
will have upper layer setup 1:1 mapping between hardware queue and CPU
queue and avoid unnecessary locking when issuing I/O.

Link: https://lore.kernel.org/r/1567790660-48142-1-git-send-email-longli@linuxonhyperv.com

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent 4b062e7c

drivers/scsi/storvsc_drv.c

+1 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1837,8 +1837,7 @@ static int storvsc_probe(struct hv_device *device,
	/*		/*
	* Set the number of HW queues we are supporting.		* Set the number of HW queues we are supporting.
	*/		*/
	if (stor_device->num_sc != 0)		host->nr_hw_queues = num_present_cpus();
	host->nr_hw_queues = stor_device->num_sc + 1;

	/*		/*
	* Set the error handler work queue.		* Set the error handler work queue.