Gerd Hoffmann
2019-Jul-02 14:18 UTC
[PATCH v6 08/18] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing
Rework fencing workflow, starting with virtio_gpu_execbuffer_ioctl.
Stop using ttm helpers, use the virtio_gpu_array_* helpers (which work
on the reservation objects directly) instead.
New workflow:
(1) All gem objects needed by a command are added to a
virtio_gpu_object_array.
(2) All reservation objects will be locked (virtio_gpu_array_lock_resv).
(3) virtio_gpu_fence_emit() completes fence initialization.
(4) fence gets added to the objects, reservation objects are unlocked
(virtio_gpu_array_add_fence, virtio_gpu_array_unlock_resv).
(5) virtio command is submitted to the host.
(6) The completion callback (virtio_gpu_dequeue_ctrl_func)
will drop object references and free virtio_gpu_object_array.
v6: rewrite most of the patch.
Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
drivers/gpu/drm/virtio/virtgpu_drv.h | 6 ++-
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 56 +++++++++-----------------
drivers/gpu/drm/virtio/virtgpu_vq.c | 21 +++++++---
3 files changed, 38 insertions(+), 45 deletions(-)
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index abb078a5dedf..98511d1dfff2 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -121,9 +121,9 @@ struct virtio_gpu_vbuffer {
char *resp_buf;
int resp_size;
-
virtio_gpu_resp_cb resp_cb;
+ struct virtio_gpu_object_array *objs;
struct list_head list;
};
@@ -318,7 +318,9 @@ void virtio_gpu_cmd_context_detach_resource(struct
virtio_gpu_device *vgdev,
uint32_t resource_id);
void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev,
void *data, uint32_t data_size,
- uint32_t ctx_id, struct virtio_gpu_fence *fence);
+ uint32_t ctx_id,
+ struct virtio_gpu_object_array *objs,
+ struct virtio_gpu_fence *fence);
void virtio_gpu_cmd_transfer_from_host_3d(struct virtio_gpu_device *vgdev,
uint32_t resource_id, uint32_t ctx_id,
uint64_t offset, uint32_t level,
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 0caff3fa623e..9735d7e5899b 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -105,16 +105,11 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device
*dev, void *data,
struct drm_virtgpu_execbuffer *exbuf = data;
struct virtio_gpu_device *vgdev = dev->dev_private;
struct virtio_gpu_fpriv *vfpriv = drm_file->driver_priv;
- struct drm_gem_object *gobj;
struct virtio_gpu_fence *out_fence;
- struct virtio_gpu_object *qobj;
int ret;
uint32_t *bo_handles = NULL;
void __user *user_bo_handles = NULL;
- struct list_head validate_list;
- struct ttm_validate_buffer *buflist = NULL;
- int i;
- struct ww_acquire_ctx ticket;
+ struct virtio_gpu_object_array *buflist = NULL;
struct sync_file *sync_file;
int in_fence_fd = exbuf->fence_fd;
int out_fence_fd = -1;
@@ -155,15 +150,10 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device
*dev, void *data,
return out_fence_fd;
}
- INIT_LIST_HEAD(&validate_list);
if (exbuf->num_bo_handles) {
-
bo_handles = kvmalloc_array(exbuf->num_bo_handles,
- sizeof(uint32_t), GFP_KERNEL);
- buflist = kvmalloc_array(exbuf->num_bo_handles,
- sizeof(struct ttm_validate_buffer),
- GFP_KERNEL | __GFP_ZERO);
- if (!bo_handles || !buflist) {
+ sizeof(uint32_t), GFP_KERNEL);
+ if (!bo_handles) {
ret = -ENOMEM;
goto out_unused_fd;
}
@@ -175,25 +165,21 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device
*dev, void *data,
goto out_unused_fd;
}
- for (i = 0; i < exbuf->num_bo_handles; i++) {
- gobj = drm_gem_object_lookup(drm_file, bo_handles[i]);
- if (!gobj) {
- ret = -ENOENT;
- goto out_unused_fd;
- }
-
- qobj = gem_to_virtio_gpu_obj(gobj);
- buflist[i].bo = &qobj->tbo;
-
- list_add(&buflist[i].head, &validate_list);
+ buflist = virtio_gpu_array_from_handles(drm_file, bo_handles,
+ exbuf->num_bo_handles);
+ if (!buflist) {
+ ret = -ENOENT;
+ goto out_unused_fd;
}
kvfree(bo_handles);
bo_handles = NULL;
}
- ret = virtio_gpu_object_list_validate(&ticket, &validate_list);
- if (ret)
- goto out_free;
+ if (buflist) {
+ ret = virtio_gpu_array_lock_resv(buflist);
+ if (ret)
+ goto out_unused_fd;
+ }
buf = memdup_user(u64_to_user_ptr(exbuf->command), exbuf->size);
if (IS_ERR(buf)) {
@@ -220,24 +206,18 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device
*dev, void *data,
}
virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
- vfpriv->ctx_id, out_fence);
-
- ttm_eu_fence_buffer_objects(&ticket, &validate_list,
&out_fence->f);
-
- /* fence the command bo */
- virtio_gpu_unref_list(&validate_list);
- kvfree(buflist);
+ vfpriv->ctx_id, buflist, out_fence);
return 0;
out_memdup:
kfree(buf);
out_unresv:
- ttm_eu_backoff_reservation(&ticket, &validate_list);
-out_free:
- virtio_gpu_unref_list(&validate_list);
+ if (buflist)
+ virtio_gpu_array_unlock_resv(buflist);
out_unused_fd:
kvfree(bo_handles);
- kvfree(buflist);
+ if (buflist)
+ virtio_gpu_array_put_free(buflist);
if (out_fence_fd >= 0)
put_unused_fd(out_fence_fd);
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c
b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 6c1a90717535..dbe329801e84 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -191,7 +191,7 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work)
} while (!virtqueue_enable_cb(vgdev->ctrlq.vq));
spin_unlock(&vgdev->ctrlq.qlock);
- list_for_each_entry_safe(entry, tmp, &reclaim_list, list) {
+ list_for_each_entry(entry, &reclaim_list, list) {
resp = (struct virtio_gpu_ctrl_hdr *)entry->resp_buf;
trace_virtio_gpu_cmd_response(vgdev->ctrlq.vq, resp);
@@ -218,14 +218,18 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct
*work)
}
if (entry->resp_cb)
entry->resp_cb(vgdev, entry);
-
- list_del(&entry->list);
- free_vbuf(vgdev, entry);
}
wake_up(&vgdev->ctrlq.ack_queue);
if (fence_id)
virtio_gpu_fence_event_process(vgdev, fence_id);
+
+ list_for_each_entry_safe(entry, tmp, &reclaim_list, list) {
+ if (entry->objs)
+ virtio_gpu_array_put_free(entry->objs);
+ list_del(&entry->list);
+ free_vbuf(vgdev, entry);
+ }
}
void virtio_gpu_dequeue_cursor_func(struct work_struct *work)
@@ -337,6 +341,10 @@ static int virtio_gpu_queue_fenced_ctrl_buffer(struct
virtio_gpu_device *vgdev,
if (fence)
virtio_gpu_fence_emit(vgdev, hdr, fence);
+ if (vbuf->objs) {
+ virtio_gpu_array_add_fence(vbuf->objs, &fence->f);
+ virtio_gpu_array_unlock_resv(vbuf->objs);
+ }
rc = virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf);
spin_unlock(&vgdev->ctrlq.qlock);
return rc;
@@ -939,7 +947,9 @@ void virtio_gpu_cmd_transfer_from_host_3d(struct
virtio_gpu_device *vgdev,
void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev,
void *data, uint32_t data_size,
- uint32_t ctx_id, struct virtio_gpu_fence *fence)
+ uint32_t ctx_id,
+ struct virtio_gpu_object_array *objs,
+ struct virtio_gpu_fence *fence)
{
struct virtio_gpu_cmd_submit *cmd_p;
struct virtio_gpu_vbuffer *vbuf;
@@ -949,6 +959,7 @@ void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev,
vbuf->data_buf = data;
vbuf->data_size = data_size;
+ vbuf->objs = objs;
cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_SUBMIT_3D);
cmd_p->hdr.ctx_id = cpu_to_le32(ctx_id);
--
2.18.1
Chia-I Wu
2019-Jul-03 18:49 UTC
[PATCH v6 08/18] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing
On Tue, Jul 2, 2019 at 7:19 AM Gerd Hoffmann <kraxel at redhat.com> wrote:> > Rework fencing workflow, starting with virtio_gpu_execbuffer_ioctl. > Stop using ttm helpers, use the virtio_gpu_array_* helpers (which work > on the reservation objects directly) instead. > > New workflow: > > (1) All gem objects needed by a command are added to a > virtio_gpu_object_array. > (2) All reservation objects will be locked (virtio_gpu_array_lock_resv). > (3) virtio_gpu_fence_emit() completes fence initialization. > (4) fence gets added to the objects, reservation objects are unlocked > (virtio_gpu_array_add_fence, virtio_gpu_array_unlock_resv). > (5) virtio command is submitted to the host. > (6) The completion callback (virtio_gpu_dequeue_ctrl_func) > will drop object references and free virtio_gpu_object_array. > > v6: rewrite most of the patch. > > Signed-off-by: Gerd Hoffmann <kraxel at redhat.com> > --- > drivers/gpu/drm/virtio/virtgpu_drv.h | 6 ++- > drivers/gpu/drm/virtio/virtgpu_ioctl.c | 56 +++++++++----------------- > drivers/gpu/drm/virtio/virtgpu_vq.c | 21 +++++++--- > 3 files changed, 38 insertions(+), 45 deletions(-) > > diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h > index abb078a5dedf..98511d1dfff2 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_drv.h > +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h > @@ -121,9 +121,9 @@ struct virtio_gpu_vbuffer { > > char *resp_buf; > int resp_size; > - > virtio_gpu_resp_cb resp_cb; > > + struct virtio_gpu_object_array *objs; > struct list_head list; > }; > > @@ -318,7 +318,9 @@ void virtio_gpu_cmd_context_detach_resource(struct virtio_gpu_device *vgdev, > uint32_t resource_id); > void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev, > void *data, uint32_t data_size, > - uint32_t ctx_id, struct virtio_gpu_fence *fence); > + uint32_t ctx_id, > + struct virtio_gpu_object_array *objs, > + struct virtio_gpu_fence *fence); > void virtio_gpu_cmd_transfer_from_host_3d(struct virtio_gpu_device *vgdev, > uint32_t resource_id, uint32_t ctx_id, > uint64_t offset, uint32_t level, > diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > index 0caff3fa623e..9735d7e5899b 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c > +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > @@ -105,16 +105,11 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data, > struct drm_virtgpu_execbuffer *exbuf = data; > struct virtio_gpu_device *vgdev = dev->dev_private; > struct virtio_gpu_fpriv *vfpriv = drm_file->driver_priv; > - struct drm_gem_object *gobj; > struct virtio_gpu_fence *out_fence; > - struct virtio_gpu_object *qobj; > int ret; > uint32_t *bo_handles = NULL; > void __user *user_bo_handles = NULL; > - struct list_head validate_list; > - struct ttm_validate_buffer *buflist = NULL; > - int i; > - struct ww_acquire_ctx ticket; > + struct virtio_gpu_object_array *buflist = NULL; > struct sync_file *sync_file; > int in_fence_fd = exbuf->fence_fd; > int out_fence_fd = -1; > @@ -155,15 +150,10 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data, > return out_fence_fd; > } > > - INIT_LIST_HEAD(&validate_list); > if (exbuf->num_bo_handles) { > - > bo_handles = kvmalloc_array(exbuf->num_bo_handles, > - sizeof(uint32_t), GFP_KERNEL); > - buflist = kvmalloc_array(exbuf->num_bo_handles, > - sizeof(struct ttm_validate_buffer), > - GFP_KERNEL | __GFP_ZERO); > - if (!bo_handles || !buflist) { > + sizeof(uint32_t), GFP_KERNEL); > + if (!bo_handles) { > ret = -ENOMEM; > goto out_unused_fd; > } > @@ -175,25 +165,21 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data, > goto out_unused_fd; > } > > - for (i = 0; i < exbuf->num_bo_handles; i++) { > - gobj = drm_gem_object_lookup(drm_file, bo_handles[i]); > - if (!gobj) { > - ret = -ENOENT; > - goto out_unused_fd; > - } > - > - qobj = gem_to_virtio_gpu_obj(gobj); > - buflist[i].bo = &qobj->tbo; > - > - list_add(&buflist[i].head, &validate_list); > + buflist = virtio_gpu_array_from_handles(drm_file, bo_handles, > + exbuf->num_bo_handles); > + if (!buflist) { > + ret = -ENOENT; > + goto out_unused_fd; > } > kvfree(bo_handles); > bo_handles = NULL; > } > > - ret = virtio_gpu_object_list_validate(&ticket, &validate_list); > - if (ret) > - goto out_free; > + if (buflist) { > + ret = virtio_gpu_array_lock_resv(buflist); > + if (ret) > + goto out_unused_fd; > + } > > buf = memdup_user(u64_to_user_ptr(exbuf->command), exbuf->size); > if (IS_ERR(buf)) { > @@ -220,24 +206,18 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data, > } > > virtio_gpu_cmd_submit(vgdev, buf, exbuf->size, > - vfpriv->ctx_id, out_fence); > - > - ttm_eu_fence_buffer_objects(&ticket, &validate_list, &out_fence->f); > - > - /* fence the command bo */ > - virtio_gpu_unref_list(&validate_list); > - kvfree(buflist); > + vfpriv->ctx_id, buflist, out_fence); > return 0; > > out_memdup: > kfree(buf); > out_unresv: > - ttm_eu_backoff_reservation(&ticket, &validate_list); > -out_free: > - virtio_gpu_unref_list(&validate_list); > + if (buflist) > + virtio_gpu_array_unlock_resv(buflist); > out_unused_fd: > kvfree(bo_handles); > - kvfree(buflist); > + if (buflist) > + virtio_gpu_array_put_free(buflist); > > if (out_fence_fd >= 0) > put_unused_fd(out_fence_fd); > diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c > index 6c1a90717535..dbe329801e84 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_vq.c > +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c > @@ -191,7 +191,7 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work) > } while (!virtqueue_enable_cb(vgdev->ctrlq.vq)); > spin_unlock(&vgdev->ctrlq.qlock); > > - list_for_each_entry_safe(entry, tmp, &reclaim_list, list) { > + list_for_each_entry(entry, &reclaim_list, list) { > resp = (struct virtio_gpu_ctrl_hdr *)entry->resp_buf; > > trace_virtio_gpu_cmd_response(vgdev->ctrlq.vq, resp); > @@ -218,14 +218,18 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work) > } > if (entry->resp_cb) > entry->resp_cb(vgdev, entry); > - > - list_del(&entry->list); > - free_vbuf(vgdev, entry); > } > wake_up(&vgdev->ctrlq.ack_queue); > > if (fence_id) > virtio_gpu_fence_event_process(vgdev, fence_id); > + > + list_for_each_entry_safe(entry, tmp, &reclaim_list, list) { > + if (entry->objs) > + virtio_gpu_array_put_free(entry->objs); > + list_del(&entry->list); > + free_vbuf(vgdev, entry); > + } > } > > void virtio_gpu_dequeue_cursor_func(struct work_struct *work) > @@ -337,6 +341,10 @@ static int virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev, > > if (fence) > virtio_gpu_fence_emit(vgdev, hdr, fence); > + if (vbuf->objs) { > + virtio_gpu_array_add_fence(vbuf->objs, &fence->f); > + virtio_gpu_array_unlock_resv(vbuf->objs); > + }This is with the spinlock held. Maybe we should move the virtio_gpu_array_unlock_resv call out of the critical section. I am actually more concerned about virtio_gpu_array_add_fence, but it is also harder to move. Should we add a kref to the object array? This bothers me because I recently ran into a CPU-bound game with very bad lock contention here.> rc = virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf); > spin_unlock(&vgdev->ctrlq.qlock); > return rc; > @@ -939,7 +947,9 @@ void virtio_gpu_cmd_transfer_from_host_3d(struct virtio_gpu_device *vgdev, > > void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev, > void *data, uint32_t data_size, > - uint32_t ctx_id, struct virtio_gpu_fence *fence) > + uint32_t ctx_id, > + struct virtio_gpu_object_array *objs, > + struct virtio_gpu_fence *fence) > { > struct virtio_gpu_cmd_submit *cmd_p; > struct virtio_gpu_vbuffer *vbuf; > @@ -949,6 +959,7 @@ void virtio_gpu_cmd_submit(struct virtio_gpu_device *vgdev, > > vbuf->data_buf = data; > vbuf->data_size = data_size; > + vbuf->objs = objs; > > cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_SUBMIT_3D); > cmd_p->hdr.ctx_id = cpu_to_le32(ctx_id); > -- > 2.18.1 >
Gerd Hoffmann
2019-Jul-04 11:25 UTC
[PATCH v6 08/18] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing
Hi,> > if (fence) > > virtio_gpu_fence_emit(vgdev, hdr, fence); > > + if (vbuf->objs) { > > + virtio_gpu_array_add_fence(vbuf->objs, &fence->f); > > + virtio_gpu_array_unlock_resv(vbuf->objs); > > + } > This is with the spinlock held. Maybe we should move the > virtio_gpu_array_unlock_resv call out of the critical section.That would bring back the race ...> I am actually more concerned about virtio_gpu_array_add_fence, but it > is also harder to move. Should we add a kref to the object array?Yep, refcounting would be the other way to fix the race.> This bothers me because I recently ran into a CPU-bound game with very > bad lock contention here.Hmm. Any clue where this comes from? Multiple threads competing for virtio buffers I guess? Maybe we should have larger virtqueues? cheers, Gerd
Maybe Matching Threads
- [PATCH v6 08/18] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing
- [PATCH v5 08/12] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing
- [PATCH v5 08/12] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing
- [PATCH v2 07/12] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing
- [PATCH v2 07/12] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing