From b774f93d87e198481680873b22c2a443e10c3f93 Mon Sep 17 00:00:00 2001 From: Xie Yongji <xieyongji@bytedance.com> Date: Thu, 23 Mar 2023 13:30:43 +0800 Subject: [PATCH] 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: Xie Yongji <xieyongji@bytedance.com> Acked-by: Jason Wang <jasowang@redhat.com> Message-Id: <20230323053043.35-12-xieyongji@bytedance.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- drivers/vdpa/vdpa_user/vduse_dev.c | 45 +++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c index ccca84d51a28..34eebdf030af 100644 --- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -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 }; -- 2.30.9