5 ms·

It's surprising by importance but not by size, which is actually a sweet spot for evaluating a new systems language - a small dependency that everything uses.

mgaunard 3y ago
It's just an Android thing which could arguably be entirely in userspace.
- jeroenhd 3y ago
  That's something that comes up more often, because many feel this shouldn't be in the kernel in the first place. The problem is that there hasn't been a proper userspace alternative with similar performance characteristics. I think putting this stuff in the kernel is rather silly, but I'd rather have it in the kernel than bring back the rift between Android and Linux.
  - HankB99 3y ago
    Does the isolation between processes in Android require that it be in the kernel or can some other form of privilege bridge the separation?
  - mgaunard 3y ago
    "similar performance characteristics"? I can exchange data at a quarter of the latency using normal shared memory.
    - jeroenhd 3y ago
      I'm not sure how you'd port binder's security guarantees to simple shared memory. Binder is more than just IPC, it also provides an RPC mechanism as well as some isolation capabilities.
      - mgaunard 3y ago
        I'm sure it does more things that make it useful, and that it provides a practical programming model for certain platforms, but it's certainly not the lowest latency way to do inter-process communication.
- pjmlp 3y ago
  Given the microkernel-like approach taken by Project Treble, at least some part of it needs to live on the kernel for fast message interchange.
  - agent327 3y ago
    The only thing that needs to live in the kernel is fast message interchange. And that could also be used as the base mechanism to move all(!) of the drivers out of the kernel.
    - speed_spread 3y ago
      I was just mulling this over yesterday with the story about USB tablet driver regression. Running drivers as user processes would essentially give the kernel a stable ABI. But then we'd see a proliferation of closed-source drivers - there wouldn't be motivation to upstream hardware support anymore. Is that a hidden goal behind this fast IPC thingy?
    - pjmlp 3y ago
      Since Android 8 that the only in-kernel drivers are what the Android team considers legacy drivers, aka standard Linux kernel drivers pre-Project Treble. Hence why modern Android drivers are called Binderized drivers. https://source.android.com/docs/core/architecture/hal https://source.android.com/docs/core/architecture/hal

mgaunard 3y ago

It's just an Android thing which could arguably be entirely in userspace.

jeroenhd 3y ago
That's something that comes up more often, because many feel this shouldn't be in the kernel in the first place. The problem is that there hasn't been a proper userspace alternative with similar performance characteristics. I think putting this stuff in the kernel is rather silly, but I'd rather have it in the kernel than bring back the rift between Android and Linux.
- HankB99 3y ago
  Does the isolation between processes in Android require that it be in the kernel or can some other form of privilege bridge the separation?
- mgaunard 3y ago
  "similar performance characteristics"? I can exchange data at a quarter of the latency using normal shared memory.
  - jeroenhd 3y ago
    I'm not sure how you'd port binder's security guarantees to simple shared memory. Binder is more than just IPC, it also provides an RPC mechanism as well as some isolation capabilities.
    - mgaunard 3y ago
      I'm sure it does more things that make it useful, and that it provides a practical programming model for certain platforms, but it's certainly not the lowest latency way to do inter-process communication.
pjmlp 3y ago
Given the microkernel-like approach taken by Project Treble, at least some part of it needs to live on the kernel for fast message interchange.
- agent327 3y ago
  The only thing that needs to live in the kernel is fast message interchange. And that could also be used as the base mechanism to move all(!) of the drivers out of the kernel.
  - speed_spread 3y ago
    I was just mulling this over yesterday with the story about USB tablet driver regression. Running drivers as user processes would essentially give the kernel a stable ABI. But then we'd see a proliferation of closed-source drivers - there wouldn't be motivation to upstream hardware support anymore. Is that a hidden goal behind this fast IPC thingy?
  - pjmlp 3y ago
    Since Android 8 that the only in-kernel drivers are what the Android team considers legacy drivers, aka standard Linux kernel drivers pre-Project Treble. Hence why modern Android drivers are called Binderized drivers. https://source.android.com/docs/core/architecture/hal https://source.android.com/docs/core/architecture/hal