hakmem/core/box/tiny_class_policy_box.h

// tiny_class_policy_box.h - Class-scoped policy box for Tiny front-end
//
// Purpose:
//   - Centralize per-class feature toggles (Page Box / Warm Pool / caps).
//   - Keep hot paths free from direct ENV parsing or scattered conditionals.
//   - Defaults:
//       legacy (デフォルト): Page Box は C5–C7、Warm は C0–C7 で cap は小さめ
//       c5_7_only: Page/Warm とも C5–C7 のみ
//       tinyplus_all: 予備プロファイル（当面 legacy と同等）
//   - ENV: HAKMEM_TINY_POLICY_PROFILE=legacy|c5_7_only|tinyplus_all
//   - Learner が入るまでは固定ポリシーで運用し、Hot path は tiny_policy_get() を見るだけに保つ。

#ifndef TINY_CLASS_POLICY_BOX_H
#define TINY_CLASS_POLICY_BOX_H

#include <stdatomic.h>
#include <stdint.h>
#include <stdlib.h>
#include "../hakmem_tiny_config.h"

typedef struct TinyClassPolicy {
    uint8_t page_box_enabled;  // Enable Tiny Page Box for this class
    uint8_t warm_enabled;      // Enable Warm Pool for this class
    uint8_t warm_cap;          // Max warm SuperSlabs to keep (per-thread)
    uint8_t tls_carve_enabled; // Enable Warm→TLS carve experiment for this class
} TinyClassPolicy;

extern TinyClassPolicy g_tiny_class_policy[TINY_NUM_CLASSES];

// ENV-gated policy logging (default ON; disable with HAKMEM_TINY_POLICY_LOG=0)
static inline int tiny_policy_log_enabled(void) {
    static int g_policy_log = -1;
    if (__builtin_expect(g_policy_log == -1, 0)) {
        const char* e = getenv("HAKMEM_TINY_POLICY_LOG");
        g_policy_log = (e && *e && *e != '0') ? 1 : 0;
    }
    return g_policy_log;
}

// Initialize policy table once (idempotent).
void tiny_class_policy_init_once(void);

// Refresh auto profile based on learner output (no-op for non-auto profiles)
void tiny_class_policy_refresh_auto(void);

// True when active profile is "auto" (learner-managed)
int tiny_class_policy_is_auto(void);

// Debug helper: dump current policy (tag optional)
void tiny_class_policy_dump(const char* tag);

// Lightweight accessor for hot paths.
static inline const TinyClassPolicy* tiny_policy_get(int class_idx) {
    if (class_idx < 0 || class_idx >= TINY_NUM_CLASSES) {
        return NULL;
    }
    tiny_class_policy_init_once();
    return &g_tiny_class_policy[class_idx];
}

#endif // TINY_CLASS_POLICY_BOX_H