| Message ID | 1566243316-113690-1-git-send-email-longli@linuxonhyperv.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | storvsc: setup 1:1 mapping between hardware queue and CPU queue | expand |
On Tue, Aug 20, 2019 at 3:36 AM <longli@linuxonhyperv.com> wrote: > > 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; > + } Block layer provides the helper of blk_mq_map_queues(), so suggest you to use the default cpu mapping, instead of inventing a new one. thanks, Ming Lei
>>>Subject: Re: [PATCH] storvsc: setup 1:1 mapping between hardware queue >>>and CPU queue >>> >>>On Tue, Aug 20, 2019 at 3:36 AM <longli@linuxonhyperv.com> wrote: >>>> >>>> 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; >>>> + } >>> >>>Block layer provides the helper of blk_mq_map_queues(), so suggest you >>>to use the default cpu mapping, instead of inventing a new one. Thanks for the pointer. I'm sending a v2. Long >>> >>>thanks, >>>Ming Lei
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.