diff options
| author | Long Li <longli@microsoft.com> | 2020-01-14 03:08:36 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2020-01-16 07:02:24 +0300 |
| commit | 7b571c19d4c0b78d27dd3bf1f3c42e4032390af6 (patch) | |
| tree | fb61a98dda7889e07c6641f02792019275f9b04a /drivers/scsi | |
| parent | 42ec15ceaea74b5f7a621fc6686cbf69ca66c4cf (diff) | |
| download | linux-7b571c19d4c0b78d27dd3bf1f3c42e4032390af6.tar.xz | |
scsi: storvsc: Correctly set number of hardware queues for IDE disk
Commit 0ed881027690 ("scsi: storvsc: setup 1:1 mapping between hardware
queue and CPU queue") introduced a regression for disks attached to
IDE. For these disks the host VSP only offers one VMBUS channel. Setting
multiple queues can overload the VMBUS channel and result in performance
drop for high queue depth workload on system with large number of CPUs.
Fix it by leaving the number of hardware queues to 1 (default value) for
IDE disks.
Fixes: 0ed881027690 ("scsi: storvsc: setup 1:1 mapping between hardware queue and CPU queue")
Link: https://lore.kernel.org/r/1578960516-108228-1-git-send-email-longli@linuxonhyperv.com
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/storvsc_drv.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index f8faf8b3d965..fb41636519ee 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -1842,9 +1842,11 @@ static int storvsc_probe(struct hv_device *device, */ host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT); /* + * For non-IDE disks, the host supports multiple channels. * Set the number of HW queues we are supporting. */ - host->nr_hw_queues = num_present_cpus(); + if (!dev_is_ide) + host->nr_hw_queues = num_present_cpus(); /* * Set the error handler work queue. |