On Mon, Aug 26, 2019 at 04:57:22PM +0200, Christian König wrote: > This is the new dma_fence_array based container for shared fences in the > dma_resv object. > > Advantage of this approach is that you can grab a reference to the > current set of shared fences at any time, which allows us to drop the > sequence number increment and makes the whole RCU handling much more > easier. > > Disadvantage is that RCU users now have to grab a reference instead of > using the sequence counter. As far as I can see i915 was actually the > only driver doing this. > > So we optimize for adding more fences instead of reading them now. > > Another behavior change worth noting is that the shared fences are now > only visible after unlocking the dma_resv object or calling > dma_resv_fences_commit() manually. I think more specific point for publishing fences makes a lot of sense, so this sounds like a solid improvement on the dma_resv api. I'm working on some dma_fence instrumentation where that at least might be useful. /me back to burried state Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
