diff options
| author | Gerd Hoffmann <kraxel@redhat.com> | 2019-08-13 11:25:09 +0300 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2019-08-28 10:28:06 +0300 |
| commit | 744583ecc3d7c5e27d48ff74e575b893637f4b57 (patch) | |
| tree | 96305451b58691edc9b66e8821ce8b9870963e93 /drivers/gpu/drm/virtio/virtgpu_vq.c | |
| parent | 4100a7b834389e91638a0b789399fd7b31e258c1 (diff) | |
| download | linux-744583ecc3d7c5e27d48ff74e575b893637f4b57.tar.xz | |
drm/virtio: notify virtqueues without holding spinlock
Split virtqueue_kick() call into virtqueue_kick_prepare(), which
requires serialization, and virtqueue_notify(), which does not. Move
the virtqueue_notify() call out of the critical section protected by the
queue lock. This avoids triggering a vmexit while holding the lock and
thereby fixes a rather bad spinlock contention.
Suggested-by: Chia-I Wu <olvaffe@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20190813082509.29324-3-kraxel@redhat.com
Diffstat (limited to 'drivers/gpu/drm/virtio/virtgpu_vq.c')
| -rw-r--r-- | drivers/gpu/drm/virtio/virtgpu_vq.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c index ca91e83ffaef..e41c96143342 100644 --- a/drivers/gpu/drm/virtio/virtgpu_vq.c +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c @@ -252,7 +252,7 @@ void virtio_gpu_dequeue_cursor_func(struct work_struct *work) wake_up(&vgdev->cursorq.ack_queue); } -static void virtio_gpu_queue_ctrl_buffer_locked(struct virtio_gpu_device *vgdev, +static bool virtio_gpu_queue_ctrl_buffer_locked(struct virtio_gpu_device *vgdev, struct virtio_gpu_vbuffer *vbuf) __releases(&vgdev->ctrlq.qlock) __acquires(&vgdev->ctrlq.qlock) @@ -260,10 +260,11 @@ static void virtio_gpu_queue_ctrl_buffer_locked(struct virtio_gpu_device *vgdev, struct virtqueue *vq = vgdev->ctrlq.vq; struct scatterlist *sgs[3], vcmd, vout, vresp; int outcnt = 0, incnt = 0; + bool notify = false; int ret; if (!vgdev->vqs_ready) - return; + return notify; sg_init_one(&vcmd, vbuf->buf, vbuf->size); sgs[outcnt + incnt] = &vcmd; @@ -292,16 +293,21 @@ retry: trace_virtio_gpu_cmd_queue(vq, (struct virtio_gpu_ctrl_hdr *)vbuf->buf); - virtqueue_kick(vq); + notify = virtqueue_kick_prepare(vq); } + return notify; } static void virtio_gpu_queue_ctrl_buffer(struct virtio_gpu_device *vgdev, struct virtio_gpu_vbuffer *vbuf) { + bool notify; + spin_lock(&vgdev->ctrlq.qlock); - virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf); + notify = virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf); spin_unlock(&vgdev->ctrlq.qlock); + if (notify) + virtqueue_notify(vgdev->ctrlq.vq); } static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev, @@ -310,6 +316,7 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev, struct virtio_gpu_fence *fence) { struct virtqueue *vq = vgdev->ctrlq.vq; + bool notify; again: spin_lock(&vgdev->ctrlq.qlock); @@ -330,8 +337,10 @@ again: if (fence) virtio_gpu_fence_emit(vgdev, hdr, fence); - virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf); + notify = virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf); spin_unlock(&vgdev->ctrlq.qlock); + if (notify) + virtqueue_notify(vgdev->ctrlq.vq); } static void virtio_gpu_queue_cursor(struct virtio_gpu_device *vgdev, @@ -339,6 +348,7 @@ static void virtio_gpu_queue_cursor(struct virtio_gpu_device *vgdev, { struct virtqueue *vq = vgdev->cursorq.vq; struct scatterlist *sgs[1], ccmd; + bool notify; int ret; int outcnt; @@ -361,10 +371,13 @@ retry: trace_virtio_gpu_cmd_queue(vq, (struct virtio_gpu_ctrl_hdr *)vbuf->buf); - virtqueue_kick(vq); + notify = virtqueue_kick_prepare(vq); } spin_unlock(&vgdev->cursorq.qlock); + + if (notify) + virtqueue_notify(vq); } /* just create gem objects for userspace and long lived objects, |