netris-nestri/build/kernel/scx.fragment

# Merged after nestri.fragment when KERNEL_SCX=1: what a sched_ext scheduler
# needs from the kernel it is loaded into. Off by default, because a guest that
# does not load one pays for the tracing and debug-info support below and gets
# nothing back.
#
# A scheduler is a BPF program attached through struct_ops, and the loader
# checks the kernel's own symbols, BTF and config before it will attach.
# Each group below is one of those checks; the failure when it is missing is
# the loader's, not the kernel's, and says little.

# The class itself, and the BPF it is loaded through. struct_ops resolves a
# member's stub function by address, so it needs kallsyms.
CONFIG_SCHED_CLASS_EXT=y
CONFIG_BPF_SYSCALL=y
CONFIG_BPF_JIT=y
CONFIG_KALLSYMS=y

# Type information for the kernel's own structures. The stock fragment turns
# debug info off, and BTF is built from it, so that is undone here. A scheduler reads task
# fields by BTF, and resolves per-CPU variables such as the preempt count by
# name, which kallsyms only lists with KALLSYMS_ALL.
# CONFIG_DEBUG_INFO_NONE is not set
CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
CONFIG_DEBUG_INFO_BTF=y
CONFIG_KALLSYMS_ALL=y

# The loader reads the running kernel's config from /proc/config.gz to decide
# which features to use.
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y

# Tracing the loader checks for and attaches to: debugfs to find it, and
# function and syscall tracepoints for the futex hooks some schedulers use to
# boost a lock holder.
CONFIG_DEBUG_FS=y
CONFIG_FTRACE=y
CONFIG_FUNCTION_TRACER=y
CONFIG_DYNAMIC_FTRACE=y
CONFIG_FPROBE=y
CONFIG_FTRACE_SYSCALLS=y
CONFIG_KPROBES=y
CONFIG_KPROBE_EVENTS=y

# Utilisation hints a scheduler can read from a task.
CONFIG_UCLAMP_TASK=y
CONFIG_UCLAMP_TASK_GROUP=y