On Mon, 30 Oct 2023 02:02:03 +0300
Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx> wrote:
> Prepare for addition of memory shrinker support by attaching shmem pages
> to host dynamically on first use. Previously the attachment vq command
> wasn't fenced and there was no vq kick made in the BO creation code path,
> hence the attachment already was happening dynamically, but implicitly.
> Making attachment explicitly dynamic will allow to simplify and reuse more
> code when shrinker will be added. The virtio_gpu_object_shmem_init() now
> works under the held reservation lock, which will be important to have for
> shrinker to avoid moving pages while they are in active use by the driver.
Ah, this commit might actually help getting rid of the workaround
introduced in "drm/shmem-helper: Add common memory shrinker".
>
> Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/virtio/virtgpu_drv.h | 7 +++
> drivers/gpu/drm/virtio/virtgpu_gem.c | 26 +++++++++
> drivers/gpu/drm/virtio/virtgpu_ioctl.c | 32 +++++++----
> drivers/gpu/drm/virtio/virtgpu_object.c | 73 ++++++++++++++++++++-----
> drivers/gpu/drm/virtio/virtgpu_submit.c | 15 ++++-
> 5 files changed, 125 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 56269814fb6d..421f524ae1de 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -89,6 +89,7 @@ struct virtio_gpu_object {
> uint32_t hw_res_handle;
> bool dumb;
> bool created;
> + bool detached;
> bool host3d_blob, guest_blob;
> uint32_t blob_mem, blob_flags;
>
> @@ -313,6 +314,8 @@ void virtio_gpu_array_put_free(struct virtio_gpu_object_array *objs);
> void virtio_gpu_array_put_free_delayed(struct virtio_gpu_device *vgdev,
> struct virtio_gpu_object_array *objs);
> void virtio_gpu_array_put_free_work(struct work_struct *work);
> +int virtio_gpu_array_prepare(struct virtio_gpu_device *vgdev,
> + struct virtio_gpu_object_array *objs);
> int virtio_gpu_gem_pin(struct virtio_gpu_object *bo);
> void virtio_gpu_gem_unpin(struct virtio_gpu_object *bo);
>
> @@ -453,6 +456,10 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
>
> bool virtio_gpu_is_shmem(struct virtio_gpu_object *bo);
>
> +int virtio_gpu_reattach_shmem_object_locked(struct virtio_gpu_object *bo);
> +
> +int virtio_gpu_reattach_shmem_object(struct virtio_gpu_object *bo);
> +
> int virtio_gpu_resource_id_get(struct virtio_gpu_device *vgdev,
> uint32_t *resid);
> /* virtgpu_prime.c */
> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
> index 625c05d625bf..97e67064c97e 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> @@ -295,6 +295,26 @@ void virtio_gpu_array_put_free_work(struct work_struct *work)
> spin_unlock(&vgdev->obj_free_lock);
> }
>
> +int virtio_gpu_array_prepare(struct virtio_gpu_device *vgdev,
> + struct virtio_gpu_object_array *objs)
> +{
> + struct virtio_gpu_object *bo;
> + int ret = 0;
> + u32 i;
> +
> + for (i = 0; i < objs->nents; i++) {
> + bo = gem_to_virtio_gpu_obj(objs->objs[i]);
> +
> + if (virtio_gpu_is_shmem(bo) && bo->detached) {
> + ret = virtio_gpu_reattach_shmem_object_locked(bo);
> + if (ret)
> + break;
> + }
> + }
> +
> + return ret;
> +}
> +
> int virtio_gpu_gem_pin(struct virtio_gpu_object *bo)
> {
> int err;
> @@ -303,6 +323,12 @@ int virtio_gpu_gem_pin(struct virtio_gpu_object *bo)
> err = drm_gem_shmem_pin(&bo->base);
> if (err)
> return err;
> +
> + err = virtio_gpu_reattach_shmem_object(bo);
> + if (err) {
> + drm_gem_shmem_unpin(&bo->base);
> + return err;
> + }
> }
>
> return 0;
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index b24b11f25197..070c29cea26a 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -246,6 +246,10 @@ static int virtio_gpu_transfer_from_host_ioctl(struct drm_device *dev,
> if (ret != 0)
> goto err_put_free;
>
> + ret = virtio_gpu_array_prepare(vgdev, objs);
> + if (ret)
> + goto err_unlock;
> +
> fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, 0);
> if (!fence) {
> ret = -ENOMEM;
> @@ -288,11 +292,25 @@ static int virtio_gpu_transfer_to_host_ioctl(struct drm_device *dev, void *data,
> goto err_put_free;
> }
>
> + ret = virtio_gpu_array_lock_resv(objs);
> + if (ret != 0)
> + goto err_put_free;
> +
> + ret = virtio_gpu_array_prepare(vgdev, objs);
> + if (ret)
> + goto err_unlock;
> +
> + fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, 0);
> + if (!fence) {
> + ret = -ENOMEM;
> + goto err_unlock;
> + }
> +
> if (!vgdev->has_virgl_3d) {
> virtio_gpu_cmd_transfer_to_host_2d
> (vgdev, offset,
> args->box.w, args->box.h, args->box.x, args->box.y,
> - objs, NULL);
> + objs, fence);
> } else {
> virtio_gpu_create_context(dev, file);
>
> @@ -301,23 +319,13 @@ static int virtio_gpu_transfer_to_host_ioctl(struct drm_device *dev, void *data,
> goto err_put_free;
> }
>
> - ret = virtio_gpu_array_lock_resv(objs);
> - if (ret != 0)
> - goto err_put_free;
> -
> - ret = -ENOMEM;
> - fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context,
> - 0);
> - if (!fence)
> - goto err_unlock;
> -
> virtio_gpu_cmd_transfer_to_host_3d
> (vgdev,
> vfpriv ? vfpriv->ctx_id : 0, offset, args->level,
> args->stride, args->layer_stride, &args->box, objs,
> fence);
> - dma_fence_put(&fence->f);
> }
> + dma_fence_put(&fence->f);
> virtio_gpu_notify(vgdev);
> return 0;
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
> index 998f8b05ceb1..000bb7955a57 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -143,7 +143,7 @@ static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
> struct sg_table *pages;
> int si;
>
> - pages = drm_gem_shmem_get_pages_sgt(&bo->base);
> + pages = drm_gem_shmem_get_pages_sgt_locked(&bo->base);
> if (IS_ERR(pages))
> return PTR_ERR(pages);
>
> @@ -177,6 +177,40 @@ static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
> return 0;
> }
>
> +int virtio_gpu_reattach_shmem_object_locked(struct virtio_gpu_object *bo)
> +{
> + struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
> + struct virtio_gpu_mem_entry *ents;
> + unsigned int nents;
> + int err;
> +
> + if (!bo->detached)
> + return 0;
> +
> + err = virtio_gpu_object_shmem_init(vgdev, bo, &ents, &nents);
> + if (err)
> + return err;
> +
> + virtio_gpu_object_attach(vgdev, bo, ents, nents);
> +
> + bo->detached = false;
> +
> + return 0;
> +}
> +
> +int virtio_gpu_reattach_shmem_object(struct virtio_gpu_object *bo)
> +{
> + int ret;
> +
> + ret = dma_resv_lock_interruptible(bo->base.base.resv, NULL);
> + if (ret)
> + return ret;
> + ret = virtio_gpu_reattach_shmem_object_locked(bo);
> + dma_resv_unlock(bo->base.base.resv);
> +
> + return ret;
> +}
> +
> int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
> struct virtio_gpu_object_params *params,
> struct virtio_gpu_object **bo_ptr,
> @@ -207,45 +241,56 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
>
> bo->dumb = params->dumb;
>
> - ret = virtio_gpu_object_shmem_init(vgdev, bo, &ents, &nents);
> - if (ret != 0)
> - goto err_put_id;
> + if (bo->blob_mem == VIRTGPU_BLOB_MEM_GUEST)
> + bo->guest_blob = true;
>
> if (fence) {
> ret = -ENOMEM;
> objs = virtio_gpu_array_alloc(1);
> if (!objs)
> - goto err_free_entry;
> + goto err_put_id;
> virtio_gpu_array_add_obj(objs, &bo->base.base);
>
> ret = virtio_gpu_array_lock_resv(objs);
> if (ret != 0)
> goto err_put_objs;
> + } else {
> + ret = dma_resv_lock(bo->base.base.resv, NULL);
> + if (ret)
> + goto err_put_id;
> }
>
> if (params->blob) {
> - if (params->blob_mem == VIRTGPU_BLOB_MEM_GUEST)
> - bo->guest_blob = true;
> + ret = virtio_gpu_object_shmem_init(vgdev, bo, &ents, &nents);
> + if (ret)
> + goto err_unlock_objs;
> + } else {
> + bo->detached = true;
> + }
>
> + if (params->blob)
> virtio_gpu_cmd_resource_create_blob(vgdev, bo, params,
> ents, nents);
> - } else if (params->virgl) {
> + else if (params->virgl)
> virtio_gpu_cmd_resource_create_3d(vgdev, bo, params,
> objs, fence);
> - virtio_gpu_object_attach(vgdev, bo, ents, nents);
> - } else {
> + else
> virtio_gpu_cmd_create_resource(vgdev, bo, params,
> objs, fence);
> - virtio_gpu_object_attach(vgdev, bo, ents, nents);
> - }
> +
> + if (!fence)
> + dma_resv_unlock(bo->base.base.resv);
>
> *bo_ptr = bo;
> return 0;
>
> +err_unlock_objs:
> + if (fence)
> + virtio_gpu_array_unlock_resv(objs);
> + else
> + dma_resv_unlock(bo->base.base.resv);
> err_put_objs:
> virtio_gpu_array_put_free(objs);
> -err_free_entry:
> - kvfree(ents);
> err_put_id:
> virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
> err_put_pages:
> diff --git a/drivers/gpu/drm/virtio/virtgpu_submit.c b/drivers/gpu/drm/virtio/virtgpu_submit.c
> index 5c514946bbad..6e4ef2593e8f 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_submit.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_submit.c
> @@ -464,8 +464,19 @@ static void virtio_gpu_install_out_fence_fd(struct virtio_gpu_submit *submit)
>
> static int virtio_gpu_lock_buflist(struct virtio_gpu_submit *submit)
> {
> - if (submit->buflist)
> - return virtio_gpu_array_lock_resv(submit->buflist);
> + int err;
> +
> + if (submit->buflist) {
> + err = virtio_gpu_array_lock_resv(submit->buflist);
> + if (err)
> + return err;
> +
> + err = virtio_gpu_array_prepare(submit->vgdev, submit->buflist);
> + if (err) {
> + virtio_gpu_array_unlock_resv(submit->buflist);
> + return err;
> + }
> + }
>
> return 0;
> }
