DMA-BUF Explicit Sync Improvements Being Discussed To Help Vulkan, Other Modern Users

Intel's lead developer of the ANV Vulkan Linux driver started a discussion last week about adding an API to DMA-BUF for importing/exporting of sync files as part of allowing for explicit synchronization capabilities in better handling of modern APIs from user-space.

The proposal adds importing/exporting of synchronization files to DMA-BUF, the buffer sharing and synchronization framework widely used throughout the Linux kernel at this point. This in turn would open up user-space to being able to manage fences attached to a DMA-BUF buffer. This proposal would still allow explicit and implicit synchronization paths to co-exist for DMA-BUF depending upon the user-space component and gradually moving more user-space code to an explicit synchronization model.

The proposal for this DMA-BUF improvement is currently laid out on the kernel mailing list.

AMD open-source driver developer Christian König expressed interest in the concept. For exporting of sync files he referred to it as an "absolutely great idea" though pointed out in the current design the importing could allow security issues. Christian noted, "See we can't allow userspace to mess with DMA-buf fences in that way because it rips open a security hole you can push an elephant through."

It will be interesting to see where this work around DMA-BUF explicit synchronization handling for user-space progresses as the year moves on.