dmaengine: idxd: add support for configurable max wq batch size

Add sysfs attribute max_batch_size to wq in order to allow the max batch
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>
Link: https://lore.kernel.org/r/159865273617.29141.4383066301730821749.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/Documentation/ABI/stable/sysfs-driver-dma-idxd b/Documentation/ABI/stable/sysfs-driver-dma-idxd
index 452f353..a2bc4af 100644 (file)
--- a/Documentation/ABI/stable/sysfs-driver-dma-idxd
+++ b/Documentation/ABI/stable/sysfs-driver-dma-idxd
@@ -177,6 +177,13 @@ Contact:   dmaengine@vger.kernel.org
 Description:   The max transfer sized for this workqueue. Cannot exceed device
                max transfer size. Configurable parameter.
 
+What:          /sys/bus/dsa/devices/wq<m>.<n>/max_batch_size
+Date:          Aug 28, 2020
+KernelVersion: 5.10.0
+Contact:       dmaengine@vger.kernel.org
+Description:   The max batch size for this workqueue. Cannot exceed device
+               max batch size. Configurable parameter.
+
 What:           /sys/bus/dsa/devices/engine<m>.<n>/group_id
 Date:           Oct 25, 2019
 KernelVersion:  5.6.0

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index b8dbb70..00dab14 100644 (file)
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -530,7 +530,7 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
 
        /* bytes 12-15 */
        wq->wqcfg.max_xfer_shift = ilog2(wq->max_xfer_bytes);
-       wq->wqcfg.max_batch_shift = idxd->hw.gen_cap.max_batch_shift;
+       wq->wqcfg.max_batch_shift = ilog2(wq->max_batch_size);
 
        dev_dbg(dev, "WQ %d CFGs\n", wq->id);
        for (i = 0; i < 8; i++) {

diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 81db2a4..e8bec6e 100644 (file)
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -115,6 +115,7 @@ struct idxd_wq {
        struct dma_chan dma_chan;
        char name[WQ_NAME_SIZE + 1];
        u64 max_xfer_bytes;
+       u32 max_batch_size;
 };
 
 struct idxd_engine {

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index e5ed575..11e5ce1 100644 (file)
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -177,6 +177,7 @@ static int idxd_setup_internals(struct idxd_device *idxd)
                mutex_init(&wq->wq_lock);
                wq->idxd_cdev.minor = -1;
                wq->max_xfer_bytes = idxd->max_xfer_bytes;
+               wq->max_batch_size = idxd->max_batch_size;
        }
 
        for (i = 0; i < idxd->max_engines; i++) {

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index a3bac72..e6284cb 100644 (file)
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -1064,6 +1064,21 @@ 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 int __get_sysfs_u64(const char *buf, u64 *val)
+{
+       int rc;
+
+       rc = kstrtou64(buf, 0, val);
+       if (rc < 0)
+               return -EINVAL;
+
+       if (*val == 0)
+               return -EINVAL;
+
+       *val = roundup_pow_of_two(*val);
+       return 0;
+}
+
 static ssize_t wq_max_transfer_size_show(struct device *dev, struct device_attribute *attr,
                                         char *buf)
 {
@@ -1083,14 +1098,10 @@ static ssize_t wq_max_transfer_size_store(struct device *dev, struct device_attr
        if (wq->state != IDXD_WQ_DISABLED)
                return -EPERM;
 
-       rc = kstrtou64(buf, 0, &xfer_size);
+       rc = __get_sysfs_u64(buf, &xfer_size);
        if (rc < 0)
-               return -EINVAL;
-
-       if (xfer_size == 0)
-               return -EINVAL;
+               return rc;
 
-       xfer_size = roundup_pow_of_two(xfer_size);
        if (xfer_size > idxd->max_xfer_bytes)
                return -EINVAL;
 
@@ -1103,6 +1114,39 @@ 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 ssize_t wq_max_batch_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, "%u\n", wq->max_batch_size);
+}
+
+static ssize_t wq_max_batch_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 batch_size;
+       int rc;
+
+       if (wq->state != IDXD_WQ_DISABLED)
+               return -EPERM;
+
+       rc = __get_sysfs_u64(buf, &batch_size);
+       if (rc < 0)
+               return rc;
+
+       if (batch_size > idxd->max_batch_size)
+               return -EINVAL;
+
+       wq->max_batch_size = (u32)batch_size;
+
+       return count;
+}
+
+static struct device_attribute dev_attr_wq_max_batch_size =
+               __ATTR(max_batch_size, 0644, wq_max_batch_size_show, wq_max_batch_size_store);
+
 static struct attribute *idxd_wq_attributes[] = {
        &dev_attr_wq_clients.attr,
        &dev_attr_wq_state.attr,
@@ -1114,6 +1158,7 @@ static struct attribute *idxd_wq_attributes[] = {
        &dev_attr_wq_name.attr,
        &dev_attr_wq_cdev_minor.attr,
        &dev_attr_wq_max_transfer_size.attr,
+       &dev_attr_wq_max_batch_size.attr,
        NULL,
 };