linux/common-config: enable options needed to use sched-ext schedulers #351977
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| BPF_SYSCALL = yes; | ||
| SCHED_CLASS_EXT = whenAtLeast "6.12" yes; | ||
| BPF_JIT = whenPlatformHasEBPFJit yes; | ||
| BPF_JIT_ALWAYS_ON = whenPlatformHasEBPFJit (whenAtLeast "6.12" yes); # whenPlatformHasEBPFJit yes; # see https://github.com/NixOS/nixpkgs/issues/79304 |
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It was disabled by default, due to tests.installer.simpleUefiSystemdBoot.x86_64-linux failing (#79304). I moved the option around and enabled it for 6.12+.
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I extremely doubt that it's actually necessary.
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Well the kernel docs recommend to enable it, that's why I made the change.
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I would like to see stronger justification than "the kernel docs say to enable it for this one feature". CONFIG_SCHED_CLASS_EXT does not actually depend on it, and enabling it comes with performance and security implications.
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I realise that some options are already enabled/disabled in other sub categories, but to "better group" these for sched-ext I moved some things around. Please feel free to edit my branch/point out if I made a mistake.
(Note: this is my first change to kernel config, so go easy on me if I messed up)
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@ofborg test tests.installer.simpleUefiSystemdBoot.x86_64-linux |
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Diffing the configuration file, this is the only change: Which I fundamentally do not think should be applied without much stronger justification. |
Sched-ext support has been merged to 6.12 tree, this commit enables the feature accross Nixpkgs kernels 6.12+. `BPF_JIT_DEFAULT_ON`, `PAHOLE_HAS_SPLIT_BTF` and `PAHOLE_HAS_BTF_TAG` are enabled by default in config scripts. Docs: https://www.kernel.org/doc/html/v6.12-rc2/scheduler/sched-ext.html#switching-to-and-from-sched-ext
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I am not entirely sure about the inner workings, though I suspect that as it's in the kernel docs for sched-ext, without it |
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Don't guess. |
Sched-ext support has been merged to 6.12 tree, this commit enables the feature accross Nixpkgs kernels 6.12+.
Docs: https://www.kernel.org/doc/html/v6.12-rc2/scheduler/sched-ext.html#switching-to-and-from-sched-ext
Possible regressions
tests.installer.simpleUefiSystemdBoot.x86_64-linuxmay fail, see #79304.