Commit b774f93d authored by Xie Yongji's avatar Xie Yongji Committed by Michael S. Tsirkin
Browse files

vduse: Support specifying bounce buffer size via sysfs 

As discussed in [1], this adds sysfs interface to support
specifying bounce buffer size in virtio-vdpa case. It would
be a performance tuning parameter for high throughput workloads.

[1] https://lore.kernel.org/netdev/e8f25a35-9d45-69f9-795d-bdbbb90337a3@redhat.com/



Signed-off-by: default avatarXie Yongji <xieyongji@bytedance.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Message-Id: <20230323053043.35-12-xieyongji@bytedance.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent d4438d23

drivers/vdpa/vdpa_user/vduse_dev.c

+44 −1
Original line number Diff line number Diff line
@@ -37,8 +37,11 @@ 
#define DRV_LICENSE  "GPL v2"



#define VDUSE_DEV_MAX (1U << MINORBITS)

#define VDUSE_MAX_BOUNCE_SIZE (1024 * 1024 * 1024)

#define VDUSE_MIN_BOUNCE_SIZE (1024 * 1024)

#define VDUSE_BOUNCE_SIZE (64 * 1024 * 1024)

#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)

/* 128 MB reserved for virtqueue creation */

#define VDUSE_IOVA_SIZE (VDUSE_MAX_BOUNCE_SIZE + 128 * 1024 * 1024)

#define VDUSE_MSG_DEFAULT_TIMEOUT 30



#define IRQ_UNBOUND -1
@@ -1715,8 +1718,48 @@ static ssize_t msg_timeout_store(struct device *device, 


static DEVICE_ATTR_RW(msg_timeout);



static ssize_t bounce_size_show(struct device *device,

				struct device_attribute *attr, char *buf)

{

	struct vduse_dev *dev = dev_get_drvdata(device);



	return sysfs_emit(buf, "%u\n", dev->bounce_size);

}



static ssize_t bounce_size_store(struct device *device,

				 struct device_attribute *attr,

				 const char *buf, size_t count)

{

	struct vduse_dev *dev = dev_get_drvdata(device);

	unsigned int bounce_size;

	int ret;



	ret = -EPERM;

	mutex_lock(&dev->domain_lock);

	if (dev->domain)

		goto unlock;



	ret = kstrtouint(buf, 10, &bounce_size);

	if (ret < 0)

		goto unlock;



	ret = -EINVAL;

	if (bounce_size > VDUSE_MAX_BOUNCE_SIZE ||

	    bounce_size < VDUSE_MIN_BOUNCE_SIZE)

		goto unlock;



	dev->bounce_size = bounce_size & PAGE_MASK;

	ret = count;

unlock:

	mutex_unlock(&dev->domain_lock);

	return ret;

}



static DEVICE_ATTR_RW(bounce_size);



static struct attribute *vduse_dev_attrs[] = {

	&dev_attr_msg_timeout.attr,

	&dev_attr_bounce_size.attr,

	NULL

};