990080 - TiledLayerBufferComposite::RecycleCallback() is not called from second time.

Status: RESOLVED FIXED

(Core :: Graphics: Layers, defect)

Description

[Sotaro Ikeda [:sotaro]]

+++ This bug was initially created as a clone of Bug #977880 +++

Within TiledLayerBufferComposite::RecycleCallback(), TextureParent::CompositorRecycle() is called. TextureParent::CompositorRecycle() is originally created for SimpleTextureClient. It expects that TextureParent::RecvClientRecycle() is called from child side. In the function increment TextureHost's reference count by holding TextureHost's pointer to TextureParent::mWaitForClientRecycle. 

But TiledLayerBufferComposite does not expect it. Therefore, since TiledLayerBufferComposite::RecycleCallback() is called once, TextuteHost's reference count is kept more than 2. Then TiledLayerBufferComposite::RecycleCallback() is not called after once called.

TiledLayerBufferComposite::RecycleCallback() is called when TextuteHost's  reference count becomes one.

Comment 1

[Sotaro Ikeda [:sotaro]]

Nominate to 1.4 blocker. This bug could regress bug 977880.

Comment 2

[Jason Smith [:jsmith]]

What's the user impact? Is there a performance hit from this?

Comment 3

[Sotaro Ikeda [:sotaro]]

(In reply to Jason Smith [:jsmith] from comment #2)
> What's the user impact? Is there a performance hit from this?

There is no performance impact. This could case, flicker or artifact problem on tiled thebes layers.

Comment 4

[Sotaro Ikeda [:sotaro]]

(In reply to Sotaro Ikeda [:sotaro] from comment #3)
> (In reply to Jason Smith [:jsmith] from comment #2)
> > What's the user impact? Is there a performance hit from this?
> 
> There is no performance impact. This could case, flicker or artifact problem
> on tiled thebes layers.

This is a potential problem. Even Bug 977880 is very hard to reproduce. I could not reproduce it.

Comment 5

[Sotaro Ikeda [:sotaro]]

There seems 2 choices to solve the problem.
- [1] Adding argument to TextureParent::CompositorRecycle() to differentiate the recycling. When TiledLayerBufferComposite's case, do not call the following.
>   mWaitForClientRecycle = mTextureHost;

- [2] Change SimpleTiledContentClient as not to use TextureParent::RecvClientRecycle().


[1] is simpler way to fix the problem.

Comment 6

[Chris Lord [:cwiiis]]

Is this only a problem with SimpleTiledContentClient? If so, is it particularly urgent?

Comment 7

[Sotaro Ikeda [:sotaro]]

This is a potential problem of ClientTiledThebesLayer, not of SimpleTiledContentClient. The reason of "potential" is that no one can re-generate bug 977880 in recent rom.

SimpleTiledContentClient uses TextureParent::CompositorRecycle() as recycling. But ClientTiledThebesLayer uses it just as Fence delivery. TextureParent::CompositorRecycle() does not care about the difference. It causes ClientTiledThebesLayer's TextureHost reference count more than 2.

Comment 8

[Sotaro Ikeda [:sotaro]]

(In reply to Chris Lord [:cwiiis] from comment #6)
> Is this only a problem with SimpleTiledContentClient? If so, is it
> particularly urgent?

This is a potential problem as comment 7. So, not urgent in my understanding.

Comment 9

[Sotaro Ikeda [:sotaro]]

Next week BenWa is going to look into this bug.

Comment 10

[Sotaro Ikeda [:sotaro]]

Attachment: patch - Prepare for the next reycle, only if TextureClient request it

On JB gonk, TiledContentHost uses recycling only on Host side. This patch handle the case.

Comment 11

[Sotaro Ikeda [:sotaro]]

https://hg.mozilla.org/integration/b2g-inbound/rev/7b4b11ff5f9c

Comment 12

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/7b4b11ff5f9c