[PATCH 1/4] [RFC]drm: add syncobj timeline support v6

Zhou, David(ChunMing) David1.Zhou at amd.com
Wed Sep 19 08:03:12 UTC 2018



> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
> Christian K?nig
> Sent: Wednesday, September 19, 2018 3:45 PM
> To: Zhou, David(ChunMing) <David1.Zhou at amd.com>; Zhou,
> David(ChunMing) <David1.Zhou at amd.com>; dri-
> devel at lists.freedesktop.org
> Cc: Dave Airlie <airlied at redhat.com>; Rakos, Daniel
> <Daniel.Rakos at amd.com>; Daniel Vetter <daniel at ffwll.ch>; amd-
> gfx at lists.freedesktop.org
> Subject: Re: [PATCH 1/4] [RFC]drm: add syncobj timeline support v6
> 
> Am 19.09.2018 um 09:32 schrieb zhoucm1:
> >
> >
> > On 2018年09月19日 15:18, Christian König wrote:
> >> Am 19.09.2018 um 06:26 schrieb Chunming Zhou:
> > [snip]
> >>>           *fence = NULL;
> >>>           drm_syncobj_add_callback_locked(syncobj, cb, func); @@
> >>> -164,6 +177,153 @@ void drm_syncobj_remove_callback(struct
> >>> drm_syncobj *syncobj,
> >>>       spin_unlock(&syncobj->lock);
> >>>   }
> >>>   +static void drm_syncobj_timeline_init(struct drm_syncobj
> >>> *syncobj)
> >>
> >> We still have _timeline_ in the name here.
> > the func is relevant to timeline members, or which name is proper?
> 
> Yeah, but we now use the timeline implementation for the individual syncobj
> as well.
> 
> Not a big issue, but I would just name it
> drm_syncobj_init()/drm_syncobj_fini.

There is already drm_syncobj_init/fini in drm_syncboj.c , any other name can be suggested?

> 
> >
> >>
> >>> +{
> >>> +    spin_lock(&syncobj->lock);
> >>> +    syncobj->timeline_context = dma_fence_context_alloc(1);
> > [snip]
> >>> +}
> >>> +
> >>> +int drm_syncobj_lookup_fence(struct drm_syncobj *syncobj, u64
> >>> +point,
> >>> +               struct dma_fence **fence) {
> >>> +
> >>> +    return drm_syncobj_search_fence(syncobj, point,
> >>> +                    DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT,
> >>
> >> I still have a bad feeling setting that flag as default cause it
> >> might change the behavior for the UAPI.
> >>
> >> Maybe export drm_syncobj_search_fence directly? E.g. with the flags
> >> parameter.
> > previous v5 indeed do this, you let me wrap it, need change back?
> 
> No, the problem is that drm_syncobj_find_fence() is still using
> drm_syncobj_lookup_fence() which sets the flag instead of
> drm_syncobj_search_fence() without the flag.
> 
> That changes the UAPI behavior because previously we would have returned
> an error code and now we block for a fence to appear.
> 
> So I think the right solution would be to add the flags parameter to
> drm_syncobj_find_fence() and let the driver decide if we need to block or
> get -ENOENT.

Got your means,
Exporting flag in func is easy,
 but driver doesn't pass flag, which flag is proper by default? We still need to give a default flag in patch, don't we?

Thanks,
David Zhou

> 
> Regards,
> Christian.
> 
> >
> > Regards,
> > David Zhou
> >>
> >> Regards,
> >> Christian.
> >>
> >>> +                    fence);
> >>> +}
> >>> +EXPORT_SYMBOL(drm_syncobj_lookup_fence);
> >>> +
> >>>   /**
> >>>    * drm_syncobj_find_fence - lookup and reference the fence in a
> >>> sync object
> >>>    * @file_private: drm file private pointer @@ -228,7 +443,7 @@
> >>> static int drm_syncobj_assign_null_handle(struct
> >>> drm_syncobj *syncobj)
> >>>    * @fence: out parameter for the fence
> >>>    *
> >>>    * This is just a convenience function that combines
> >>> drm_syncobj_find() and
> >>> - * drm_syncobj_fence_get().
> >>> + * drm_syncobj_lookup_fence().
> >>>    *
> >>>    * Returns 0 on success or a negative error value on failure. On
> >>> success @fence
> >>>    * contains a reference to the fence, which must be released by
> >>> calling @@ -236,18 +451,11 @@ static int
> >>> drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
> >>>    */
> >>>   int drm_syncobj_find_fence(struct drm_file *file_private,
> >>>                  u32 handle, u64 point,
> >>> -               struct dma_fence **fence) -{
> >>> +               struct dma_fence **fence) {
> >>>       struct drm_syncobj *syncobj = drm_syncobj_find(file_private,
> >>> handle);
> >>> -    int ret = 0;
> >>> -
> >>> -    if (!syncobj)
> >>> -        return -ENOENT;
> >>> +    int ret;
> >>>   -    *fence = drm_syncobj_fence_get(syncobj);
> >>> -    if (!*fence) {
> >>> -        ret = -EINVAL;
> >>> -    }
> >>> +    ret = drm_syncobj_lookup_fence(syncobj, point, fence);
> >>>       drm_syncobj_put(syncobj);
> >>>       return ret;
> >>>   }
> >>> @@ -264,7 +472,7 @@ void drm_syncobj_free(struct kref *kref)
> >>>       struct drm_syncobj *syncobj = container_of(kref,
> >>>                              struct drm_syncobj,
> >>>                              refcount);
> >>> -    drm_syncobj_replace_fence(syncobj, 0, NULL);
> >>> +    drm_syncobj_timeline_fini(syncobj);
> >>>       kfree(syncobj);
> >>>   }
> >>>   EXPORT_SYMBOL(drm_syncobj_free);
> >>> @@ -294,6 +502,11 @@ 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;
> >>> +    else
> >>> +        syncobj->type = DRM_SYNCOBJ_TYPE_INDIVIDUAL;
> >>> +    drm_syncobj_timeline_init(syncobj);
> >>>         if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
> >>>           ret = drm_syncobj_assign_null_handle(syncobj);
> >>> @@ -576,7 +789,8 @@ drm_syncobj_create_ioctl(struct drm_device
> *dev,
> >>> void *data,
> >>>           return -ENODEV;
> >>>         /* no valid flags yet */
> >>> -    if (args->flags & ~DRM_SYNCOBJ_CREATE_SIGNALED)
> >>> +    if (args->flags & ~(DRM_SYNCOBJ_CREATE_SIGNALED |
> >>> +                DRM_SYNCOBJ_CREATE_TYPE_TIMELINE))
> >>>           return -EINVAL;
> >>>         return drm_syncobj_create_as_handle(file_private,
> >>> @@ -669,9 +883,8 @@ static void syncobj_wait_syncobj_func(struct
> >>> drm_syncobj *syncobj,
> >>>       struct syncobj_wait_entry *wait =
> >>>           container_of(cb, struct syncobj_wait_entry, syncobj_cb);
> >>>   -    /* This happens inside the syncobj lock */
> >>> -    wait->fence =
> >>> dma_fence_get(rcu_dereference_protected(syncobj->fence,
> >>> - lockdep_is_held(&syncobj->lock)));
> >>> +    drm_syncobj_search_fence(syncobj, 0, 0, &wait->fence);
> >>> +
> >>>       wake_up_process(wait->task);
> >>>   }
> >>>   @@ -698,7 +911,8 @@ static signed long
> >>> drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
> >>>       signaled_count = 0;
> >>>       for (i = 0; i < count; ++i) {
> >>>           entries[i].task = current;
> >>> -        entries[i].fence = drm_syncobj_fence_get(syncobjs[i]);
> >>> +        ret = drm_syncobj_search_fence(syncobjs[i], 0, 0,
> >>> +                           &entries[i].fence);
> >>>           if (!entries[i].fence) {
> >>>               if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
> >>>                   continue;
> >>> @@ -970,12 +1184,19 @@ drm_syncobj_reset_ioctl(struct drm_device
> >>> *dev, void *data,
> >>>       if (ret < 0)
> >>>           return ret;
> >>>   -    for (i = 0; i < args->count_handles; i++)
> >>> -        drm_syncobj_replace_fence(syncobjs[i], 0, NULL);
> >>> -
> >>> +    for (i = 0; i < args->count_handles; i++) {
> >>> +        if (syncobjs[i]->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
> >>> +            DRM_ERROR("timeline syncobj cannot reset!\n");
> >>> +            ret = -EINVAL;
> >>> +            goto out;
> >>> +        }
> >>> +        drm_syncobj_timeline_fini(syncobjs[i]);
> >>> +        drm_syncobj_timeline_init(syncobjs[i]);
> >>> +    }
> >>> +out:
> >>>       drm_syncobj_array_free(syncobjs, args->count_handles);
> >>>   -    return 0;
> >>> +    return ret;
> >>>   }
> >>>     int
> >>> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> >>> b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> >>> index 0a8d2d64f380..a040fa3281df 100644
> >>> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> >>> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> >>> @@ -2137,7 +2137,7 @@ await_fence_array(struct i915_execbuffer *eb,
> >>>           if (!(flags & I915_EXEC_FENCE_WAIT))
> >>>               continue;
> >>>   -        fence = drm_syncobj_fence_get(syncobj);
> >>> +        drm_syncobj_lookup_fence(syncobj, 0, &fence);
> >>>           if (!fence)
> >>>               return -EINVAL;
> >>>   diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
> >>> index 425432b85a87..6dac479fedfe 100644
> >>> --- a/include/drm/drm_syncobj.h
> >>> +++ b/include/drm/drm_syncobj.h
> >>> @@ -30,6 +30,11 @@
> >>>     struct drm_syncobj_cb;
> >>>   +enum drm_syncobj_type {
> >>> +    DRM_SYNCOBJ_TYPE_INDIVIDUAL,
> >>> +    DRM_SYNCOBJ_TYPE_TIMELINE
> >>> +};
> >>> +
> >>>   /**
> >>>    * struct drm_syncobj - sync object.
> >>>    *
> >>> @@ -41,19 +46,36 @@ struct drm_syncobj {
> >>>        */
> >>>       struct kref refcount;
> >>>       /**
> >>> -     * @fence:
> >>> -     * NULL or a pointer to the fence bound to this object.
> >>> -     *
> >>> -     * This field should not be used directly. Use
> >>> drm_syncobj_fence_get()
> >>> -     * and drm_syncobj_replace_fence() instead.
> >>> +     * @type: indicate syncobj type
> >>> +     */
> >>> +    enum drm_syncobj_type type;
> >>> +    /**
> >>> +     * @wq: wait signal operation work queue
> >>> +     */
> >>> +    wait_queue_head_t    wq;
> >>> +    /**
> >>> +     * @timeline_context: fence context used by timeline
> >>>        */
> >>> -    struct dma_fence __rcu *fence;
> >>> +    u64 timeline_context;
> >>>       /**
> >>> -     * @cb_list: List of callbacks to call when the &fence gets
> >>> replaced.
> >>> +     * @timeline: syncobj timeline value, which indicates point is
> >>> signaled.
> >>>        */
> >>> +    u64 timeline;
> >>> +    /**
> >>> +     * @signal_point: which indicates the latest signaler point.
> >>> +     */
> >>> +    u64 signal_point;
> >>> +    /**
> >>> +     * @signal_pt_list: signaler point list.
> >>> +     */
> >>> +    struct list_head signal_pt_list;
> >>> +
> >>> +    /**
> >>> +         * @cb_list: List of callbacks to call when the &fence gets
> >>> replaced.
> >>> +         */
> >>>       struct list_head cb_list;
> >>>       /**
> >>> -     * @lock: Protects &cb_list and write-locks &fence.
> >>> +     * @lock: Protects syncobj list and write-locks &fence.
> >>>        */
> >>>       spinlock_t lock;
> >>>       /**
> >>> @@ -68,7 +90,7 @@ typedef void (*drm_syncobj_func_t)(struct
> >>> drm_syncobj *syncobj,
> >>>   /**
> >>>    * struct drm_syncobj_cb - callback for drm_syncobj_add_callback
> >>>    * @node: used by drm_syncob_add_callback to append this struct to
> >>> - *      &drm_syncobj.cb_list
> >>> + *       &drm_syncobj.cb_list
> >>>    * @func: drm_syncobj_func_t to call
> >>>    *
> >>>    * This struct will be initialized by drm_syncobj_add_callback,
> >>> additional @@ -106,29 +128,6 @@ drm_syncobj_put(struct drm_syncobj
> >>> *obj)
> >>>       kref_put(&obj->refcount, drm_syncobj_free);
> >>>   }
> >>>   -/**
> >>> - * drm_syncobj_fence_get - get a reference to a fence in a sync
> >>> object
> >>> - * @syncobj: sync object.
> >>> - *
> >>> - * This acquires additional reference to &drm_syncobj.fence
> >>> contained in @obj,
> >>> - * if not NULL. It is illegal to call this without already holding
> >>> a reference.
> >>> - * No locks required.
> >>> - *
> >>> - * Returns:
> >>> - * Either the fence of @obj or NULL if there's none.
> >>> - */
> >>> -static inline struct dma_fence *
> >>> -drm_syncobj_fence_get(struct drm_syncobj *syncobj) -{
> >>> -    struct dma_fence *fence;
> >>> -
> >>> -    rcu_read_lock();
> >>> -    fence = dma_fence_get_rcu_safe(&syncobj->fence);
> >>> -    rcu_read_unlock();
> >>> -
> >>> -    return fence;
> >>> -}
> >>> -
> >>>   struct drm_syncobj *drm_syncobj_find(struct drm_file
> >>> *file_private,
> >>>                        u32 handle);
> >>>   void drm_syncobj_replace_fence(struct drm_syncobj *syncobj, u64
> >>> point, @@ -142,5 +141,7 @@ int drm_syncobj_create(struct
> drm_syncobj
> >>> **out_syncobj, uint32_t flags,
> >>>   int drm_syncobj_get_handle(struct drm_file *file_private,
> >>>                  struct drm_syncobj *syncobj, u32 *handle);
> >>>   int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd);
> >>> +int drm_syncobj_lookup_fence(struct drm_syncobj *syncobj, u64
> >>> +point,
> >>> +                 struct dma_fence **fence);
> >>>     #endif
> >>> 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;
> >>>   };
> >>
> >
> 
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