scx_cake 1.1.1

A sched_ext scheduler applying CAKE bufferbloat concepts to CPU scheduling
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/* scx_cake/bpf/bpf_compat.h */
#ifndef __CAKE_BPF_COMPAT_H
#define __CAKE_BPF_COMPAT_H

/* Compiler abstraction: Clang 21+ uses formal atomics for MLP; <21 uses scalpel-optimized ASM */

#if defined(__clang__) && __clang_major__ >= 21

    /* MODERN PATH: Formal Atomics (Max Performance) */
    #define cake_relaxed_load_u32(ptr)      __atomic_load_n(ptr, __ATOMIC_RELAXED)
    #define cake_relaxed_store_u32(ptr, v)  __atomic_store_n(ptr, v, __ATOMIC_RELAXED)

#else

    /* COMPAT PATH: Scalpel-Optimized Inline Assembly */

    static __always_inline u32 cake_relaxed_load_u32(const volatile u32 *ptr) {
        u32 val;
        asm volatile(
            "%0 = *(u32 *)(%1 + 0)"
            : "=r"(val)
            : "r"(ptr), "m"(*ptr)  /* Targeted dependency, no global spill */
        );
        return val;
    }

    static __always_inline void cake_relaxed_store_u32(volatile u32 *ptr, u32 val) {
        asm volatile(
            "*(u32 *)(%1 + 0) = %2"
            : "=m"(*ptr)           /* Only this address modified */
            : "r"(ptr), "r"(val)
        );
    }

#endif

#endif /* __CAKE_BPF_COMPAT_H */