Releases · systemd/systemd
github.com
The systemd System and Service Manager . Contribute to systemd/systemd development by creating an account on GitHub.

Systemd 254 released and now has a new soft-reboot option:

    * A new "soft-reboot" mechanism has been added to the service manager.
      A "soft reboot" is similar to a regular reboot, except that it
      affects userspace only: the service manager shuts down any running
      services and other units, then optionally switches into a new root
      file system (mounted to /run/nextroot/), and then passes control to a
      systemd instance in the new file system which then starts the system
      up again. The kernel is not rebooted and neither is the hardware,
      firmware or boot loader. This provides a fast, lightweight mechanism
      to quickly reset or update userspace, without the latency that a full
      system reset involves. Moreover, open file descriptors may be passed
      across the soft reboot into the new system where they will be passed
      back to the originating services. This allows pinning resources
      across the reboot, thus minimizing grey-out time further. This new
      reboot mechanism is accessible via the new "systemctl soft-reboot"
      command.>
  • Toribor@corndog.socialEnglish
    651·
    1 year ago

    If I’m understanding this right it seems like a good fast way to test that services start up properly without doing a full reboot so that’s pretty nice.

  • throwawayish@lemmy.ml
    281·
    1 year ago

    Hard-reboots are no longer required on Silverblue when installing or upgrading packages (besides kernel) through rpm-ostree. Arguably one should only sparingly rely on rpm-ostree for installing packages. But it’s great to have access to soft-reboot when setting up a new system.

  • r0b0@sopuli.xyz
    10·
    1 year ago

    Also:

    When the system hibernates, information about the device and offset used is now written to a non-volatile EFI variable. On next boot the system will attempt to resume from the location indicated in this EFI variable. This should make hibernation a lot more robust, while requiring no manual configuration of the resume location.

  • Atemu@lemmy.mlEnglish
    133·
    1 year ago
    • Support for System V service scripts is now deprecated and will be removed in a future release. Please make sure to update your software now to include a native systemd unit file instead of a legacy System V script to retain compatibility with future systemd releases.

    Why is this being removed?

    I wouldn’t use it but it certainly seems handy for a quick hack and also for people who are used to the old ways.

    • dr_robot@kbin.social
      44·
      1 year ago

      Maintaining legacy options is always maintenance overhead or things you need to work around when implementing new features. I suspect that they’ve concluded that not enough people use it anymore to justify the overhead.

      • PM_ME_UR_PCAPS@lemmy.mlEnglish
        19·
        1 year ago

        Yeah it’s not like service files are difficult to write. They’re certainly easier than sysv init files

  • spez@sh.itjust.worksEnglish
    62·
    1 year ago

    So is this like that windows ‘fast boot’ or whatever it’s called thing?

    • bamboo@lemm.ee
      341·
      1 year ago

      It is nothing like that. Windows fast boot is just fancy resume from hibernation.

      • aksdb@feddit.deEnglish
        11·
        1 year ago

        It’s a mix. It hibernates what would be the result of a systemd soft-reboot, before user space starts up again.

  • Chais@sh.itjust.worksEnglish
    51·
    1 year ago

    Does that mean we will be able to update graphics drivers without a full reboot if the kernel didn’t update?

    • treadful@lemmy.zipEnglish
      213·
      1 year ago

      I don’t think any graphics drivers run in user-space, so probably not.

      • Backslash@feddit.de
        5·
        1 year ago

        Yes they do, Mesa being one. Only the close to the metal stuff and Kernel-DRM is handled in kernel space, most of the heavy stuff is done in user space.

        • treadful@lemmy.zipEnglish
          4·
          1 year ago

          Where’s the line you’re drawing? And what would be the “heavy stuff” in user-space?

          I’m far from a kernel expert, but I still have the i915 module loaded into the kernel on this bad boy, which I think most people would call a driver.

          • Backslash@feddit.de
            2·
            1 year ago

            The heavy stuff would be things like shader compilation and state management for multiple different graphics APIs (OpenGL and Vulkan mostly).

            AFAIK Linux graphics drivers are usually separated into a userspace and a kernel space component, like amdgpu on the kernel side and RADV/RadeonSI within Mesa on the userspace side. So you do not need to do a full reboot to e.g. benefit from performance optimizations within Mesa to get things like faster shader compilation or more efficient draw call submission, which I think most people care about when doing driver updates. In fact you don’t even need to soft reboot, because once Mesa is updated, all following uses of it already run the new version, all without a reboot. However if your GPU is not yet supported by the kernel side, then Mesa is of no use to you.

            That being said, yes the kernel side is a very important part of the driver, but it’s such a low-level driver that very few people would be able to do much of anything with it, which is why I made that distinction.

      • QuazarOmega@lemy.lol
        1·
        11 months ago

        Near instant? They’ve been extremely slow during the update process for me, at least. I haven’t even layered that many packages, the only reason I can think of is that those few could have pulled a ton of dependencies with them, but it’s still way too slow to me (though I still love the distro for all its other perks).