On Thu, Aug 23, 2018 at 04:25:42PM +0800, Chunming Zhou wrote:
> VK_KHR_timeline_semaphore:
> This extension introduces a new type of semaphore that has an integer payload
> identifying a point in a timeline. Such timeline semaphores support the
> following operations:
> * Host query - A host operation that allows querying the payload of the
> timeline semaphore.
> * Host wait - A host operation that allows a blocking wait for a
> timeline semaphore to reach a specified value.
> * Device wait - A device operation that allows waiting for a
> timeline semaphore to reach a specified value.
> * Device signal - A device operation that allows advancing the
> timeline semaphore to a specified value.
>
> Since it's a timeline, that means the front time point(PT) always is signaled
> before the late PT.
> a. signal PT design:
> Signal PT fence N depends on PT[N-1] fence and signal opertion fence, when
> PT[N] fence is signaled,
> the timeline will increase to value of PT[N].
> b. wait PT design:
> Wait PT fence is signaled by reaching timeline point value, when timeline is
> increasing, will compare
> wait PTs value with new timeline value, if PT value is lower than timeline
> value, then wait PT will be
> signaled, otherwise keep in list. semaphore wait operation can wait on any
> point of timeline,
> so need a RB tree to order them. And wait PT could ahead of signal PT, we
> need a sumission fence to
> perform that.
>
> v2:
> 1. remove unused DRM_SYNCOBJ_CREATE_TYPE_NORMAL. (Christian)
> 2. move unexposed denitions to .c file. (Daniel Vetter)
> 3. split up the change to drm_syncobj_find_fence() in a separate patch.
> (Christian)
> 4. split up the change to drm_syncobj_replace_fence() in a separate patch.
> 5. drop the submission_fence implementation and instead use wait_event() for
> that. (Christian)
> 6. WARN_ON(point != 0) for NORMAL type syncobj case. (Daniel Vetter)
Depending upon how it's going to be used, this is the wrong thing to do.
> TODO:
> 1. CPU query and wait on timeline semaphore.
> 2. test application (Daniel Vetter)
I also had some more suggestions, around aligning the two concepts of
future fences and at least trying to merge the timeline and the other
fence (which really is just a special case of a timeline with only 1
slot).
-Daniel
>
> Signed-off-by: Chunming Zhou <david1.z...@amd.com>
> Cc: Christian Konig <christian.koe...@amd.com>
> Cc: Dave Airlie <airl...@redhat.com>
> Cc: Daniel Rakos <daniel.ra...@amd.com>
> Cc: Daniel Vetter <dan...@ffwll.ch>
> ---
> drivers/gpu/drm/drm_syncobj.c | 383
> +++++++++++++++++++++++++++++++++++++++---
> include/drm/drm_syncobj.h | 28 +++
> include/uapi/drm/drm.h | 1 +
> 3 files changed, 389 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 6227df2cc0a4..f738d78edf65 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -56,6 +56,44 @@
> #include "drm_internal.h"
> #include <drm/drm_syncobj.h>
>
> +struct drm_syncobj_stub_fence {
> + struct dma_fence base;
> + spinlock_t lock;
> +};
> +
> +static const char *drm_syncobj_stub_fence_get_name(struct dma_fence *fence)
> +{
> + return "syncobjstub";
> +}
> +
> +static bool drm_syncobj_stub_fence_enable_signaling(struct dma_fence *fence)
> +{
> + return !dma_fence_is_signaled(fence);
> +}
> +
> +static const struct dma_fence_ops drm_syncobj_stub_fence_ops = {
> + .get_driver_name = drm_syncobj_stub_fence_get_name,
> + .get_timeline_name = drm_syncobj_stub_fence_get_name,
> + .enable_signaling = drm_syncobj_stub_fence_enable_signaling,
> + .release = NULL,
> +};
> +
> +struct drm_syncobj_wait_pt {
> + struct drm_syncobj_stub_fence base;
> + u64 value;
> + struct rb_node node;
> +};
> +struct drm_syncobj_signal_pt {
> + struct drm_syncobj_stub_fence base;
> + struct dma_fence *signal_fence;
> + struct dma_fence *pre_pt_base;
> + struct dma_fence_cb signal_cb;
> + struct dma_fence_cb pre_pt_cb;
> + struct drm_syncobj *syncobj;
> + u64 value;
> + struct list_head list;
> +};
> +
> /**
> * drm_syncobj_find - lookup and reference a sync object.
> * @file_private: drm file private pointer
> @@ -137,6 +175,150 @@ void drm_syncobj_remove_callback(struct drm_syncobj
> *syncobj,
> spin_unlock(&syncobj->lock);
> }
>
> +static void drm_syncobj_timeline_signal_wait_pts(struct drm_syncobj *syncobj)
> +{
> + struct rb_node *node = NULL;
> + struct drm_syncobj_wait_pt *wait_pt = NULL;
> +
> + spin_lock(&syncobj->lock);
> + for(node = rb_first(&syncobj->syncobj_timeline.wait_pt_tree);
> + node != NULL; ) {
> + wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
> + node = rb_next(node);
> + if (wait_pt->value <= syncobj->syncobj_timeline.timeline) {
> + dma_fence_signal(&wait_pt->base.base);
> + rb_erase(&wait_pt->node,
> + &syncobj->syncobj_timeline.wait_pt_tree);
> + RB_CLEAR_NODE(&wait_pt->node);
> + /* kfree(wait_pt) is excuted by fence put */
> + dma_fence_put(&wait_pt->base.base);
> + } else {
> + /* the loop is from left to right, the later entry
> value is
> + * bigger, so don't need to check any more */
> + break;
> + }
> + }
> + spin_unlock(&syncobj->lock);
> +}
> +
> +
> +static void pt_fence_cb(struct drm_syncobj_signal_pt *signal_pt)
> +{
> + struct dma_fence *fence = NULL;
> + struct drm_syncobj *syncobj;
> +
> + fence = signal_pt->signal_fence;
> + signal_pt->signal_fence = NULL;
> + dma_fence_put(fence);
> + fence = signal_pt->pre_pt_base;
> + signal_pt->pre_pt_base = NULL;
> + dma_fence_put(fence);
> +
> + syncobj = signal_pt->syncobj;
> + spin_lock(&syncobj->lock);
> + list_del(&signal_pt->list);
> + syncobj->syncobj_timeline.timeline = signal_pt->value;
> + spin_unlock(&syncobj->lock);
> + /* kfree(signal_pt) will be executed by below fence put */
> + dma_fence_put(&signal_pt->base.base);
> + drm_syncobj_timeline_signal_wait_pts(syncobj);
> +}
> +static void pt_signal_fence_func(struct dma_fence *fence,
> + struct dma_fence_cb *cb)
> +{
> + struct drm_syncobj_signal_pt *signal_pt =
> + container_of(cb, struct drm_syncobj_signal_pt, signal_cb);
> +
> + if (signal_pt->pre_pt_base &&
> + !dma_fence_is_signaled(signal_pt->pre_pt_base))
> + return;
> +
> + pt_fence_cb(signal_pt);
> +}
> +static void pt_pre_fence_func(struct dma_fence *fence,
> + struct dma_fence_cb *cb)
> +{
> + struct drm_syncobj_signal_pt *signal_pt =
> + container_of(cb, struct drm_syncobj_signal_pt, pre_pt_cb);
> +
> + if (signal_pt->signal_fence &&
> + !dma_fence_is_signaled(signal_pt->pre_pt_base))
> + return;
> +
> + pt_fence_cb(signal_pt);
> +}
> +
> +static int drm_syncobj_timeline_replace_fence(struct drm_syncobj *syncobj,
> + struct dma_fence *fence,
> + u64 point)
> +{
> + struct drm_syncobj_signal_pt *signal_pt =
> + kzalloc(sizeof(struct drm_syncobj_signal_pt), GFP_KERNEL);
> + struct drm_syncobj_signal_pt *tail_pt;
> + struct dma_fence *tail_pt_fence = NULL;
> + int ret = 0;
> +
> + if (!signal_pt)
> + return -ENOMEM;
> + if (syncobj->syncobj_timeline.signal_point >= point) {
> + DRM_WARN("A later signal is ready!");
> + goto out;
> + }
> + if (fence)
> + dma_fence_get(fence);
> + spin_lock(&syncobj->lock);
> + spin_lock_init(&signal_pt->base.lock);
> + dma_fence_init(&signal_pt->base.base,
> + &drm_syncobj_stub_fence_ops,
> + &signal_pt->base.lock,
> + syncobj->syncobj_timeline.timeline_context, point);
> + signal_pt->signal_fence =
> + rcu_dereference_protected(fence,
> + lockdep_is_held(&fence->lock));
> + if (!list_empty(&syncobj->syncobj_timeline.signal_pt_list)) {
> + tail_pt =
> list_last_entry(&syncobj->syncobj_timeline.signal_pt_list,
> + struct drm_syncobj_signal_pt, list);
> + tail_pt_fence = &tail_pt->base.base;
> + if (dma_fence_is_signaled(tail_pt_fence))
> + tail_pt_fence = NULL;
> + }
> + if (tail_pt_fence)
> + signal_pt->pre_pt_base =
> + dma_fence_get(rcu_dereference_protected(tail_pt_fence,
> +
> lockdep_is_held(&tail_pt_fence->lock)));
> +
> + signal_pt->value = point;
> + syncobj->syncobj_timeline.signal_point = point;
> + signal_pt->syncobj = syncobj;
> + INIT_LIST_HEAD(&signal_pt->list);
> + list_add_tail(&signal_pt->list,
> &syncobj->syncobj_timeline.signal_pt_list);
> + spin_unlock(&syncobj->lock);
> + wake_up_all(&syncobj->syncobj_timeline.wq);
> + /**
> + * Every pt is depending on signal fence and previous pt fence, add
> + * callbacks to them
> + */
> + if (!dma_fence_is_signaled(signal_pt->signal_fence))
> + dma_fence_add_callback(signal_pt->signal_fence,
> + &signal_pt->signal_cb,
> + pt_signal_fence_func);
> + else
> + pt_signal_fence_func(signal_pt->signal_fence,
> + &signal_pt->signal_cb);
> + if (signal_pt->pre_pt_base &&
> !dma_fence_is_signaled(signal_pt->pre_pt_base))
> + dma_fence_add_callback(signal_pt->pre_pt_base,
> + &signal_pt->pre_pt_cb,
> + pt_pre_fence_func);
> + else
> + pt_pre_fence_func(signal_pt->pre_pt_base,
> &signal_pt->pre_pt_cb);
> +
> +
> + return 0;
> +out:
> + kfree(signal_pt);
> + return ret;
> +}
> +
> /**
> * drm_syncobj_replace_fence - replace fence in a sync object.
> * @syncobj: Sync object to replace fence in
> @@ -152,6 +334,11 @@ void drm_syncobj_replace_fence(struct drm_syncobj
> *syncobj,
> struct dma_fence *old_fence;
> struct drm_syncobj_cb *cur, *tmp;
>
> + if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
> + drm_syncobj_timeline_replace_fence(syncobj, fence,
> + point);
> + return;
> + }
> if (fence)
> dma_fence_get(fence);
>
> @@ -174,28 +361,6 @@ void drm_syncobj_replace_fence(struct drm_syncobj
> *syncobj,
> }
> EXPORT_SYMBOL(drm_syncobj_replace_fence);
>
> -struct drm_syncobj_stub_fence {
> - struct dma_fence base;
> - spinlock_t lock;
> -};
> -
> -static const char *drm_syncobj_stub_fence_get_name(struct dma_fence *fence)
> -{
> - return "syncobjstub";
> -}
> -
> -static bool drm_syncobj_stub_fence_enable_signaling(struct dma_fence *fence)
> -{
> - return !dma_fence_is_signaled(fence);
> -}
> -
> -static const struct dma_fence_ops drm_syncobj_stub_fence_ops = {
> - .get_driver_name = drm_syncobj_stub_fence_get_name,
> - .get_timeline_name = drm_syncobj_stub_fence_get_name,
> - .enable_signaling = drm_syncobj_stub_fence_enable_signaling,
> - .release = NULL,
> -};
> -
> static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
> {
> struct drm_syncobj_stub_fence *fence;
> @@ -215,6 +380,121 @@ static int drm_syncobj_assign_null_handle(struct
> drm_syncobj *syncobj)
> return 0;
> }
>
> +static struct drm_syncobj_wait_pt *
> +drm_syncobj_timeline_lookup_wait_pt(struct drm_syncobj *syncobj, u64 point)
> +{
> + struct rb_node *node = syncobj->syncobj_timeline.wait_pt_tree.rb_node;
> + struct drm_syncobj_wait_pt *wait_pt = NULL;
> +
> +
> + spin_lock(&syncobj->lock);
> + while(node) {
> + int result = point - wait_pt->value;
> +
> + wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
> + if (result < 0)
> + node = node->rb_left;
> + else if (result > 0)
> + node = node->rb_right;
> + else
> + break;
> + }
> + spin_unlock(&syncobj->lock);
> +
> + return wait_pt;
> +}
> +
> +static struct drm_syncobj_wait_pt *
> +drm_syncobj_timeline_create_wait_pt(struct drm_syncobj *syncobj, u64 point)
> +{
> + struct drm_syncobj_wait_pt *wait_pt;
> + struct rb_node **new =
> &(syncobj->syncobj_timeline.wait_pt_tree.rb_node), *parent = NULL;
> +
> + wait_pt = kzalloc(sizeof(*wait_pt), GFP_KERNEL);
> + if (!wait_pt)
> + return NULL;
> + spin_lock_init(&wait_pt->base.lock);
> + dma_fence_init(&wait_pt->base.base,
> + &drm_syncobj_stub_fence_ops,
> + &wait_pt->base.lock,
> + syncobj->syncobj_timeline.timeline_context, point);
> + wait_pt->value = point;
> +
> + /* wait pt must be in an order, so that we can easily lookup and signal
> + * it */
> + spin_lock(&syncobj->lock);
> + if (point <= syncobj->syncobj_timeline.timeline)
> + dma_fence_signal(&wait_pt->base.base);
> + while(*new) {
> + struct drm_syncobj_wait_pt *this =
> + rb_entry(*new, struct drm_syncobj_wait_pt, node);
> + int result = wait_pt->value - this->value;
> +
> + parent = *new;
> + if (result < 0)
> + new = &((*new)->rb_left);
> + else if (result > 0)
> + new = &((*new)->rb_right);
> + else
> + goto exist;
> + }
> +
> + rb_link_node(&wait_pt->node, parent, new);
> + rb_insert_color(&wait_pt->node,
> &syncobj->syncobj_timeline.wait_pt_tree);
> + spin_unlock(&syncobj->lock);
> + return wait_pt;
> +exist:
> + spin_unlock(&syncobj->lock);
> + dma_fence_put(&wait_pt->base.base);
> + wait_pt = drm_syncobj_timeline_lookup_wait_pt(syncobj, point);
> + return wait_pt;
> +}
> +
> +static struct dma_fence *
> +drm_syncobj_timeline_point_get(struct drm_syncobj *syncobj, u64 point, u64
> flag)
> +{
> + struct drm_syncobj_wait_pt *wait_pt;
> +
> + /* already signaled, simply return a signaled stub fence */
> + if (point <= syncobj->syncobj_timeline.timeline) {
> + struct drm_syncobj_stub_fence *fence;
> +
> + fence = kzalloc(sizeof(*fence), GFP_KERNEL);
> + if (fence == NULL)
> + return NULL;
> +
> + spin_lock_init(&fence->lock);
> + dma_fence_init(&fence->base, &drm_syncobj_stub_fence_ops,
> + &fence->lock, 0, 0);
> + dma_fence_signal(&fence->base);
> + return &fence->base;
> + }
> +
> + /* check if the wait pt exists */
> + wait_pt = drm_syncobj_timeline_lookup_wait_pt(syncobj, point);
> + if (!wait_pt) {
> + /* This is a new wait pt, so create it */
> + wait_pt = drm_syncobj_timeline_create_wait_pt(syncobj, point);
> + if (!wait_pt)
> + return NULL;
> + }
> + if (wait_pt) {
> + struct dma_fence *fence;
> + int ret =
> +
> wait_event_interruptible_timeout(syncobj->syncobj_timeline.wq,
> + wait_pt->value <=
> syncobj->syncobj_timeline.signal_point,
> + msecs_to_jiffies(10000)); /* wait 10s */
> +
> + if (ret <= 0)
> + return NULL;
> + rcu_read_lock();
> + fence = dma_fence_get_rcu(&wait_pt->base.base);
> + rcu_read_unlock();
> + return fence;
> + }
> + return NULL;
> +}
> +
> /**
> * drm_syncobj_find_fence - lookup and reference the fence in a sync object
> * @file_private: drm file private pointer
> @@ -240,7 +520,17 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
> if (!syncobj)
> return -ENOENT;
>
> - *fence = drm_syncobj_fence_get(syncobj);
> + if (syncobj->type == DRM_SYNCOBJ_TYPE_NORMAL) {
> + /* NORMAL syncobj doesn't care point value */
> + WARN_ON(point != 0);
> + *fence = drm_syncobj_fence_get(syncobj);
> + } else if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
> + *fence = drm_syncobj_timeline_point_get(syncobj, point,
> +
> DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT);
> + } else {
> + DRM_ERROR("Don't support this type syncobj\n");
> + *fence = NULL;
> + }
> if (!*fence) {
> ret = -EINVAL;
> }
> @@ -249,6 +539,34 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
> }
> EXPORT_SYMBOL(drm_syncobj_find_fence);
>
> +static void drm_syncobj_timeline_fini(struct drm_syncobj *syncobj,
> + struct drm_syncobj_timeline
> *syncobj_timeline)
> +{
> + struct rb_node *node = NULL;
> + struct drm_syncobj_wait_pt *wait_pt = NULL;
> + struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp;
> +
> + spin_lock(&syncobj->lock);
> + for(node = rb_first(&syncobj_timeline->wait_pt_tree);
> + node != NULL; ) {
> + wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
> + node = rb_next(node);
> + rb_erase(&wait_pt->node,
> + &syncobj_timeline->wait_pt_tree);
> + RB_CLEAR_NODE(&wait_pt->node);
> + /* kfree(wait_pt) is excuted by fence put */
> + dma_fence_put(&wait_pt->base.base);
> + }
> + list_for_each_entry_safe(signal_pt, tmp,
> + &syncobj_timeline->signal_pt_list, list) {
> + list_del(&signal_pt->list);
> + dma_fence_put(signal_pt->signal_fence);
> + dma_fence_put(signal_pt->pre_pt_base);
> + dma_fence_put(&signal_pt->base.base);
> + }
> + spin_unlock(&syncobj->lock);
> +}
> +
> /**
> * drm_syncobj_free - free a sync object.
> * @kref: kref to free.
> @@ -261,10 +579,23 @@ void drm_syncobj_free(struct kref *kref)
> struct drm_syncobj,
> refcount);
> drm_syncobj_replace_fence(syncobj, NULL, 0);
> + drm_syncobj_timeline_fini(syncobj, &syncobj->syncobj_timeline);
> kfree(syncobj);
> }
> EXPORT_SYMBOL(drm_syncobj_free);
>
> +static void drm_syncobj_timeline_init(struct drm_syncobj_timeline
> + *syncobj_timeline)
> +{
> + syncobj_timeline->timeline_context = dma_fence_context_alloc(1);
> + syncobj_timeline->timeline = 0;
> + syncobj_timeline->signal_point = 0;
> + init_waitqueue_head(&syncobj_timeline->wq);
> +
> + syncobj_timeline->wait_pt_tree = RB_ROOT;
> + INIT_LIST_HEAD(&syncobj_timeline->signal_pt_list);
> +}
> +
> /**
> * drm_syncobj_create - create a new syncobj
> * @out_syncobj: returned syncobj
> @@ -290,6 +621,12 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj,
> uint32_t flags,
> kref_init(&syncobj->refcount);
> INIT_LIST_HEAD(&syncobj->cb_list);
> spin_lock_init(&syncobj->lock);
> + if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE) {
> + syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE;
> + drm_syncobj_timeline_init(&syncobj->syncobj_timeline);
> + } else {
> + syncobj->type = DRM_SYNCOBJ_TYPE_NORMAL;
> + }
>
> if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
> ret = drm_syncobj_assign_null_handle(syncobj);
> diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
> index 335ec501001a..342b3ced3e56 100644
> --- a/include/drm/drm_syncobj.h
> +++ b/include/drm/drm_syncobj.h
> @@ -30,6 +30,25 @@
>
> struct drm_syncobj_cb;
>
> +enum drm_syncobj_type {
> + DRM_SYNCOBJ_TYPE_NORMAL,
> + DRM_SYNCOBJ_TYPE_TIMELINE
> +};
> +
> +struct drm_syncobj_timeline {
> + wait_queue_head_t wq;
> + u64 timeline_context;
> + /**
> + * @timeline: syncobj timeline
> + */
> + u64 timeline;
> + u64 signal_point;
> +
> +
> + struct rb_root wait_pt_tree;
> + struct list_head signal_pt_list;
> +};
> +
> /**
> * struct drm_syncobj - sync object.
> *
> @@ -40,6 +59,15 @@ struct drm_syncobj {
> * @refcount: Reference count of this object.
> */
> struct kref refcount;
> + /**
> + * @type: indicate syncobj type
> + */
> + enum drm_syncobj_type type;
> + /**
> + * @syncobj_timeline: timeline
> + */
> + struct drm_syncobj_timeline syncobj_timeline;
> +
> /**
> * @fence:
> * NULL or a pointer to the fence bound to this object.
> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index 300f336633f2..cebdb2541eb7 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -717,6 +717,7 @@ struct drm_prime_handle {
> struct drm_syncobj_create {
> __u32 handle;
> #define DRM_SYNCOBJ_CREATE_SIGNALED (1 << 0)
> +#define DRM_SYNCOBJ_CREATE_TYPE_TIMELINE (1 << 1)
> __u32 flags;
> };
>
> --
> 2.14.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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