Re: [PATCH 1/2] dmaengine: idxd: add support for configurable max wq xfer size

Vinod Koul
2020-08-28T11:07:03Z

On 25-08-20, 13:25, Dave Jiang wrote:
> Add sysfs attribute max_xfer_size to wq in order to allow the max xfer
> size configured on a per wq basis. Add support code to configure
> the valid user input on wq enable. This is a performance tuning
> parameter.
>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
> drivers/dma/idxd/device.c | 2 +-
> drivers/dma/idxd/idxd.h | 1 +
> drivers/dma/idxd/init.c | 1 +
> drivers/dma/idxd/sysfs.c | 40 ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
> index 14b45853aa5f..b8dbb7001933 100644
> --- a/drivers/dma/idxd/device.c
> +++ b/drivers/dma/idxd/device.c
> @@ -529,7 +529,7 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
> wq->wqcfg.priority = wq->priority;
>
> /* bytes 12-15 */
> - wq->wqcfg.max_xfer_shift = idxd->hw.gen_cap.max_xfer_shift;
> + wq->wqcfg.max_xfer_shift = ilog2(wq->max_xfer_bytes);
> wq->wqcfg.max_batch_shift = idxd->hw.gen_cap.max_batch_shift;
>
> dev_dbg(dev, "WQ %d CFGs\n", wq->id);
> diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
> index e62b4799d189..81db2a472822 100644
> --- a/drivers/dma/idxd/idxd.h
> +++ b/drivers/dma/idxd/idxd.h
> @@ -114,6 +114,7 @@ struct idxd_wq {
> struct sbitmap_queue sbq;
> struct dma_chan dma_chan;
> char name[WQ_NAME_SIZE + 1];
> + u64 max_xfer_bytes;
> };
>
> struct idxd_engine {
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index c7c61974f20f..e5ed5750a6d0 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -176,6 +176,7 @@ static int idxd_setup_internals(struct idxd_device *idxd)
> wq->idxd = idxd;
> mutex_init(&wq->wq_lock);
> wq->idxd_cdev.minor = -1;
> + wq->max_xfer_bytes = idxd->max_xfer_bytes;
> }
>
> for (i = 0; i < idxd->max_engines; i++) {
> diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
> index dcba60953217..26b3ace66782 100644
> --- a/drivers/dma/idxd/sysfs.c
> +++ b/drivers/dma/idxd/sysfs.c
> @@ -1064,6 +1064,45 @@ static ssize_t wq_cdev_minor_show(struct device *dev,
> static struct device_attribute dev_attr_wq_cdev_minor =
> __ATTR(cdev_minor, 0444, wq_cdev_minor_show, NULL);
>
> +static ssize_t wq_max_transfer_size_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct idxd_wq *wq = container_of(dev, struct idxd_wq, conf_dev);
> +
> + return sprintf(buf, "%llu\n", wq->max_xfer_bytes);
> +}
> +
> +static ssize_t wq_max_transfer_size_store(struct device *dev, struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct idxd_wq *wq = container_of(dev, struct idxd_wq, conf_dev);
> + struct idxd_device *idxd = wq->idxd;
> + u64 xfer_size;
> + int rc;
> +
> + if (wq->state != IDXD_WQ_DISABLED)
> + return -EPERM;
> +
> + rc = kstrtou64(buf, 10, &xfer_size);
> + if (rc < 0)
> + return -EINVAL;
> +
> + if (xfer_size == 0)
> + return -EINVAL;
> +
> + xfer_size = roundup_pow_of_two(xfer_size);
> + if (xfer_size > idxd->max_xfer_bytes)
> + return -EINVAL;
> +
> + wq->max_xfer_bytes = xfer_size;
> +
> + return count;
> +}
> +
> +static struct device_attribute dev_attr_wq_max_transfer_size =
> + __ATTR(max_transfer_size, 0644,
> + wq_max_transfer_size_show, wq_max_transfer_size_store);
> +
> static struct attribute *idxd_wq_attributes[] = {
> &dev_attr_wq_clients.attr,
> &dev_attr_wq_state.attr,
> @@ -1074,6 +1113,7 @@ static struct attribute *idxd_wq_attributes[] = {
> &dev_attr_wq_type.attr,
> &dev_attr_wq_name.attr,
> &dev_attr_wq_cdev_minor.attr,
> + &dev_attr_wq_max_transfer_size.attr,

ABI update for this?

--
~Vinod