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A comment on The Linux realtime preemption endgame is near. Parent comment

Re:The Linux realtime preemption endgame is near by creshal on Friday November 17, 2023 @06:08AM (#38301933)
> Millions of lines of kernel, all of which have to be made preemptable.

~90% of those are device drivers, which you'd still need with a microkernel if you want it to run or arbitrary hardware.

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Re:The Linux realtime preemption endgame is near by dontlaugh on Friday November 17, 2023 @07:01AM (#38302358)
But crucially, drivers in a microkernel run in user space and are thus pre-emptible by default. Then the driver itself only has to worry about dealing with hardware timing when pre-empted.
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Re:The Linux realtime preemption endgame is near by creshal on Friday November 17, 2023 @07:37AM (#38302671)
Sure, but who's going to write the driver in the first place? Linux's "millions of lines of code" are a really underappreciated asset, there's tons of obscure hardware that is no longer supported by any other actively maintained OS.
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Re:The Linux realtime preemption endgame is near by dontlaugh on Friday November 17, 2023 @07:53AM (#38302825)
I also don't see how we could transition to a microkernel, indeed.
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Re:The Linux realtime preemption endgame is near by naasking on Friday November 17, 2023 @10:55AM (#38305276)
The very first "hypervisors" were actually microkernels that ran Linux as a guest. This was done with Mach on PowerPC/Mac systems, and also the L4 microkernel. That's one way.

The only downside of course, is that you don't get the isolation benefits of the microkernel for anything depending on the Linux kernel process.

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