Phase v11a-3: MID v3.5 Activation (Build Complete)

Integrated MID v3.5 into active code path, making it available for C5/C6/C7 routing.

Key Changes:
- Policy Box: Added SMALL_ROUTE_MID_V35 with ENV gates (HAKMEM_MID_V35_ENABLED, HAKMEM_MID_V35_CLASSES)
- HotBox: Implemented small_mid_v35_alloc/free with TLS-cached page allocation
- Front Gate: Wired MID_V35 routing into malloc_tiny_fast.h (priority: ULTRA > MID_V35 > V7)
- Build: Added core/smallobject_mid_v35.o to all object lists

Architecture:
- Slot sizes: C5=384B, C6=512B, C7=1024B
- Page size: 64KB (170/128/64 slots)
- Integration: ColdIface v2 (refill/retire), Stats v2 (observation), Learner v2 (dormant)

Status: Build successful, ready for A/B benchmarking
Next: Performance validation (C6-heavy, C5+C6-only, Mixed benchmarks)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Makefile

@@ -218,7 +218,7 @@ LDFLAGS += $(EXTRA_LDFLAGS)
 
 # Targets
 TARGET = test_hakmem
-OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o core/smallobject_segment_mid_v3.o core/smallobject_cold_iface_mid_v3.o core/smallobject_stats_mid_v3.o core/smallobject_learner_v2.o
+OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o core/smallobject_segment_mid_v3.o core/smallobject_cold_iface_mid_v3.o core/smallobject_stats_mid_v3.o core/smallobject_learner_v2.o core/smallobject_mid_v35.o
 OBJS = $(OBJS_BASE)
 
 # Shared library
@@ -250,7 +250,7 @@ endif
 # Benchmark targets
 BENCH_HAKMEM = bench_allocators_hakmem
 BENCH_SYSTEM = bench_allocators_system
-BENCH_HAKMEM_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o core/smallobject_segment_mid_v3.o core/smallobject_cold_iface_mid_v3.o core/smallobject_stats_mid_v3.o core/smallobject_learner_v2.o bench_allocators_hakmem.o
+BENCH_HAKMEM_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o core/smallobject_segment_mid_v3.o core/smallobject_cold_iface_mid_v3.o core/smallobject_stats_mid_v3.o core/smallobject_learner_v2.o core/smallobject_mid_v35.o bench_allocators_hakmem.o
 BENCH_HAKMEM_OBJS = $(BENCH_HAKMEM_OBJS_BASE)
 ifeq ($(POOL_TLS_PHASE1),1)
 BENCH_HAKMEM_OBJS += pool_tls.o pool_refill.o pool_tls_arena.o pool_tls_registry.o pool_tls_remote.o
@@ -427,7 +427,7 @@ test-box-refactor: box-refactor
 	./larson_hakmem 10 8 128 1024 1 12345 4
 
 # Phase 4: Tiny Pool benchmarks (properly linked with hakmem)
-TINY_BENCH_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/free_publish_box.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o core/smallobject_segment_mid_v3.o core/smallobject_cold_iface_mid_v3.o core/smallobject_stats_mid_v3.o core/smallobject_learner_v2.o
+TINY_BENCH_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/free_publish_box.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o core/smallobject_segment_mid_v3.o core/smallobject_cold_iface_mid_v3.o core/smallobject_stats_mid_v3.o core/smallobject_learner_v2.o core/smallobject_mid_v35.o
 TINY_BENCH_OBJS = $(TINY_BENCH_OBJS_BASE)
 ifeq ($(POOL_TLS_PHASE1),1)
 TINY_BENCH_OBJS += pool_tls.o pool_refill.o core/pool_tls_arena.o pool_tls_registry.o pool_tls_remote.o

core/box/smallobject_mid_v35_box.h

@@ -0,0 +1,47 @@
+// smallobject_mid_v35_box.h
+// Phase v11a-3: MID v3.5 Public API (L1 HotBox)
+//
+// Purpose:
+//   - Fast-path alloc/free for C5/C6/C7 (257-1024B range)
+//   - Uses Segment v2 + ColdIface v2 + Stats v2 + Learner v2
+//   - TLS-cached page allocation with refill/retire via ColdIface
+
+#ifndef SMALLOBJECT_MID_V35_BOX_H
+#define SMALLOBJECT_MID_V35_BOX_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// ============================================================================
+// MID v3.5 Public API (called from malloc_tiny_fast.h)
+// ============================================================================
+
+/**
+ * Allocate from MID v3.5 path
+ * @param class_idx: Size class (C5/C6/C7 only)
+ * @param size: Requested size (for validation/debugging)
+ * @return USER pointer or NULL on failure
+ */
+void* small_mid_v35_alloc(uint32_t class_idx, size_t size);
+
+/**
+ * Free to MID v3.5 path
+ * @param ptr: USER pointer to free
+ * @param class_idx: Size class (C5/C6/C7 only)
+ */
+void small_mid_v35_free(void *ptr, uint32_t class_idx);
+
+/**
+ * Initialize MID v3.5 (called from hakmem init)
+ */
+void small_mid_v35_init(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // SMALLOBJECT_MID_V35_BOX_H

core/box/smallobject_policy_v7_box.h

@@ -21,6 +21,7 @@ typedef enum {
     SMALL_ROUTE_ULTRA,      // L0: C4-C7 ULTRA (FROZEN)
     SMALL_ROUTE_V7,         // L1: SmallObject v7 (research box)
     SMALL_ROUTE_MID_V3,     // L1': MID v3 (257-768B mid/small)
+    SMALL_ROUTE_MID_V35,    // L1': MID v3.5 (v11a-3: Segment/ColdIface/Stats/Learner v2)
     SMALL_ROUTE_LEGACY,     // L1': TinyHeap v1 / Pool v1 (fallback)
 } SmallRouteKind;
 

core/front/malloc_tiny_fast.h

@@ -47,6 +47,7 @@
 #include "../box/smallobject_v6_env_box.h"  // SmallObject v6 ENV control (Phase V6-HDR-2)
 #include "../box/smallobject_hotbox_v7_box.h" // SmallObject HotBox v7 stub (Phase v7-1)
 #include "../box/smallobject_policy_v7_box.h" // Phase v7-4: Policy Box
+#include "../box/smallobject_mid_v35_box.h" // Phase v11a-3: MID v3.5 HotBox
 #include "../box/tiny_c7_ultra_box.h" // C7 ULTRA stub (UF-1, delegates to v3)
 #include "../box/tiny_c6_ultra_free_box.h" // Phase 4-2: C6 ULTRA-free (free-only, C6-only)
 #include "../box/tiny_c5_ultra_free_box.h" // Phase 5-1/5-2: C5 ULTRA-free + alloc integration
@@ -224,8 +225,18 @@ static inline void* malloc_tiny_fast(size_t size) {
         }
     }
 
-    // Phase v7-4: Check Policy Box for v7 routing (before switch)
+    // Phase v7-4: Check Policy Box for v7/MID_V35 routing (before switch)
     const SmallPolicyV7* policy = small_policy_v7_snapshot();
+
+    // Phase v11a-3: MID v3.5 routing
+    if (policy->route_kind[class_idx] == SMALL_ROUTE_MID_V35) {
+        void* v35p = small_mid_v35_alloc(class_idx, size);
+        if (TINY_HOT_LIKELY(v35p != NULL)) {
+            return v35p;
+        }
+        // v35 returned NULL -> fallback to legacy
+    }
+
     if (policy->route_kind[class_idx] == SMALL_ROUTE_V7) {
         void* v7p = small_heap_alloc_fast_v7_stub(size, (uint8_t)class_idx);
         if (TINY_HOT_LIKELY(v7p != NULL)) {
@@ -378,6 +389,17 @@ static inline int free_tiny_fast(void* ptr) {
         return 1;
     }
 
+    // Phase v11a-3: Try MID v3.5 free for C5/C6/C7
+    // For v11a-3: simple ownership check (assumes current route)
+    // For v11b: will add proper segment-based ownership check
+    const SmallPolicyV7* policy_free = small_policy_v7_snapshot();
+    if ((class_idx >= 5 && class_idx <= 7) &&
+        policy_free->route_kind[class_idx] == SMALL_ROUTE_MID_V35) {
+        small_mid_v35_free(ptr, class_idx);
+        FREE_PATH_STAT_INC(smallheap_v7_fast);  // Reuse counter for now
+        return 1;
+    }
+
     // Phase v7-5b/v7-7: Always try V7 free for supported classes (C5/C6)
     // V7 returns false if ptr is not in V7 segment.
     // This is necessary because Learner may switch routes dynamically,

core/smallobject_mid_v35.c

@@ -0,0 +1,168 @@
+// smallobject_mid_v35.c
+// Phase v11a-3: MID v3.5 HotBox implementation
+//
+// Design:
+//   - TLS-cached page for fast allocation
+//   - Refill via ColdIface when page exhausted
+//   - Retire via ColdIface when page is full
+//   - Stats/Learner integration for observability
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include "box/smallobject_mid_v35_box.h"
+#include "box/smallobject_segment_mid_v3_box.h"
+#include "box/smallobject_cold_iface_mid_v3_box.h"
+#include "tiny_region_id.h"  // For tiny_region_id_write_header
+
+// Reuse SmallPageMeta from segment implementation (matches cold_iface)
+typedef struct SmallPageMeta {
+    void *ptr;
+    uint32_t capacity;
+    uint8_t class_idx;
+    uint32_t alloc_count;
+    uint32_t free_count;
+    void *segment;
+    struct SmallPageMeta *next;
+} SmallPageMeta;
+
+// ============================================================================
+// TLS Context (per-thread fast path state)
+// ============================================================================
+
+typedef struct {
+    void *page[8];           // Current page per class
+    uint32_t offset[8];      // Allocation offset (slot index)
+    uint32_t capacity[8];    // Slots per page per class
+    SmallPageMeta *meta[8];  // Page metadata for retire check
+} SmallMidV35TlsCtx;
+
+static __thread SmallMidV35TlsCtx tls_mid_v35_ctx = {0};
+
+// ============================================================================
+// Slot Configuration (C5/C6/C7)
+// ============================================================================
+
+// Slot sizes for C5, C6, C7
+static const size_t g_slot_sizes[8] = {
+    0,     // C0: not used
+    0,     // C1: not used
+    0,     // C2: not used
+    0,     // C3: not used
+    0,     // C4: not used (ULTRA handles this)
+    384,   // C5: 257-384 bytes → 384 byte slots
+    512,   // C6: 385-512 bytes → 512 byte slots
+    1024,  // C7: 513-1024 bytes → 1024 byte slots (ULTRA handles this)
+};
+
+// Slots per 64KB page
+static const uint32_t g_slots_per_page[8] = {
+    0, 0, 0, 0, 0,
+    170,  // C5: 65536 / 384 = 170
+    128,  // C6: 65536 / 512 = 128
+    64,   // C7: 65536 / 1024 = 64
+};
+
+// ============================================================================
+// Init
+// ============================================================================
+
+void small_mid_v35_init(void) {
+    // Initialize any global state if needed
+    // For v11a-3: nothing to do (TLS is zero-initialized)
+}
+
+// ============================================================================
+// Alloc
+// ============================================================================
+
+void* small_mid_v35_alloc(uint32_t class_idx, size_t size) {
+    if (class_idx < 5 || class_idx > 7) return NULL;  // Only C5-C7
+
+    SmallMidV35TlsCtx *ctx = &tls_mid_v35_ctx;
+
+    // Fast path: allocate from TLS cached page
+    if (ctx->page[class_idx] && ctx->offset[class_idx] < ctx->capacity[class_idx]) {
+        size_t slot_size = g_slot_sizes[class_idx];
+        void *base = (char*)ctx->page[class_idx] + ctx->offset[class_idx] * slot_size;
+        ctx->offset[class_idx]++;
+
+        // Update page metadata
+        if (ctx->meta[class_idx]) {
+            ctx->meta[class_idx]->alloc_count++;
+        }
+
+        // Write header (1-byte Tiny header with class_idx)
+        // Note: Assumes HAKMEM_TINY_HEADER_CLASSIDX is enabled
+        tiny_region_id_write_header(base, class_idx);
+
+        // Return USER pointer (BASE + 1 byte header)
+        return (char*)base + 1;
+    }
+
+    // Slow path: need new page via ColdIface
+    SmallPageMeta *page = small_cold_mid_v3_refill_page(class_idx);
+    if (!page) {
+        // Fallback to legacy or return NULL
+        return NULL;
+    }
+
+    // Update TLS cache
+    ctx->page[class_idx] = page->ptr;
+    ctx->offset[class_idx] = 1;  // First slot already allocated
+    ctx->capacity[class_idx] = g_slots_per_page[class_idx];
+    ctx->meta[class_idx] = page;
+
+    // Record first allocation in page metadata
+    page->alloc_count = 1;
+
+    // Write header for first slot
+    tiny_region_id_write_header(page->ptr, class_idx);
+
+    // Return first slot (USER pointer)
+    return (char*)page->ptr + 1;
+}
+
+// ============================================================================
+// Free (Simplified: just count, no freelist yet)
+// ============================================================================
+
+void small_mid_v35_free(void *ptr, uint32_t class_idx) {
+    if (!ptr || class_idx < 5 || class_idx > 7) return;
+
+    // For v11a-3: simplified free (just increment free_count)
+    // In future phases: implement freelist for reuse
+
+    // Calculate BASE from USER pointer
+    void *base = (char*)ptr - 1;
+
+    // Find page metadata via simple calculation
+    // Note: Assumes 64KB pages aligned to 64KB boundary
+    size_t page_size = 64 * 1024;  // 64KB
+    void *page_base = (void*)((uintptr_t)base & ~(page_size - 1));
+
+    // Check if this is the current TLS page
+    SmallMidV35TlsCtx *ctx = &tls_mid_v35_ctx;
+    SmallPageMeta *meta = ctx->meta[class_idx];
+
+    if (meta && meta->ptr == page_base) {
+        // Free to current TLS page
+        meta->free_count++;
+
+        // Check if page is fully empty
+        if (meta->free_count >= meta->capacity) {
+            // Retire page via ColdIface
+            small_cold_mid_v3_retire_page(meta);
+
+            // Clear TLS cache for this class
+            ctx->page[class_idx] = NULL;
+            ctx->offset[class_idx] = 0;
+            ctx->meta[class_idx] = NULL;
+        }
+    } else {
+        // Different page: need RegionIdBox lookup
+        // For v11a-3: simple fallback - just count the free
+        // Real implementation needs proper page lookup
+        // TODO: Implement cross-page free via RegionIdBox in v11b
+    }
+}

core/smallobject_policy_v7.c

@@ -75,6 +75,23 @@ static inline uint32_t env_class_mask(const char* name, uint32_t default_mask) {
     return default_mask;
 }
 
+// ============================================================================
+// MID v3.5 ENV Helpers (Phase v11a-3)
+// ============================================================================
+
+static inline bool mid_v35_enabled(void) {
+    const char* e = getenv("HAKMEM_MID_V35_ENABLED");
+    return (e && *e && *e != '0');
+}
+
+static inline uint32_t mid_v35_class_mask(void) {
+    const char* e = getenv("HAKMEM_MID_V35_CLASSES");
+    if (e && *e) {
+        return (uint32_t)strtoul(e, NULL, 0);
+    }
+    return 0x60;  // Default: C5(0x20) + C6(0x40)
+}
+
 // ============================================================================
 // Policy Initialization from ENV
 // ============================================================================
@@ -87,7 +104,7 @@ void small_policy_v7_init_from_env(SmallPolicyV7* policy) {
         policy->route_kind[i] = SMALL_ROUTE_LEGACY;
     }
 
-    // Priority 3: MID_v3 (257-768B, C5-C6 range)
+    // Priority 4: MID_v3 (257-768B, C5-C6 range)
     // ENV: HAKMEM_MID_V3_ENABLED, HAKMEM_MID_V3_CLASSES
     if (env_enabled("HAKMEM_MID_V3_ENABLED")) {
         uint32_t mid_mask = env_class_mask("HAKMEM_MID_V3_CLASSES", 0x60); // C5-C6 default
@@ -98,6 +115,20 @@ void small_policy_v7_init_from_env(SmallPolicyV7* policy) {
         }
     }
 
+    // Priority 3: MID_v3.5 (Phase v11a-3: higher priority than MID_v3)
+    // ENV: HAKMEM_MID_V35_ENABLED, HAKMEM_MID_V35_CLASSES
+    if (mid_v35_enabled()) {
+        uint32_t v35_mask = mid_v35_class_mask();
+        for (int i = 0; i < 8; i++) {
+            if (v35_mask & (1u << i)) {
+                // Only override if not ULTRA
+                if (policy->route_kind[i] != SMALL_ROUTE_ULTRA) {
+                    policy->route_kind[i] = SMALL_ROUTE_MID_V35;
+                }
+            }
+        }
+    }
+
     // Priority 2: SmallObject v7 (research box, C6-only for now)
     // ENV: HAKMEM_SMALL_HEAP_V7_ENABLED, HAKMEM_SMALL_HEAP_V7_CLASSES
     if (env_enabled("HAKMEM_SMALL_HEAP_V7_ENABLED")) {
@@ -145,6 +176,7 @@ const char* small_route_kind_name(SmallRouteKind kind) {
         case SMALL_ROUTE_ULTRA:   return "ULTRA";
         case SMALL_ROUTE_V7:      return "V7";
         case SMALL_ROUTE_MID_V3:  return "MID_V3";
+        case SMALL_ROUTE_MID_V35: return "MID_V35";
         case SMALL_ROUTE_LEGACY:  return "LEGACY";
         default:                  return "UNKNOWN";
     }

docs/analysis/PHASE_V11A3_IMPLEMENTATION_SUMMARY.md

@@ -0,0 +1,226 @@
+# Phase v11a-3: MID v3.5 Implementation Summary
+
+**Date:** 2025-12-12
+**Status:** Build Complete - Ready for A/B Benchmarking
+**Author:** Claude Opus 4.5
+
+## Overview
+
+Phase v11a-3 successfully integrated MID v3.5 into the active code path, making it available for routing C5/C6/C7 allocations. This phase activates the Segment/ColdIface/Stats/Learner v2 infrastructure implemented in Phase v11a-2.
+
+## Implementation Tasks Completed
+
+### Task 1: Policy Box Updates (L3)
+
+**Files Modified:**
+- `/mnt/workdisk/public_share/hakmem/core/box/smallobject_policy_v7_box.h`
+- `/mnt/workdisk/public_share/hakmem/core/smallobject_policy_v7.c`
+
+**Changes:**
+1. Added `SMALL_ROUTE_MID_V35` to `SmallRouteKind` enum
+2. Implemented ENV gate functions:
+   - `mid_v35_enabled()` - checks `HAKMEM_MID_V35_ENABLED`
+   - `mid_v35_class_mask()` - reads `HAKMEM_MID_V35_CLASSES` (default: 0x60 for C5+C6)
+3. Updated policy init with priority: ULTRA > MID_V35 > V7 > MID_V3 > LEGACY
+4. Added MID_V35 case to `small_route_kind_name()`
+
+### Task 2: MID v3.5 HotBox Implementation (L1)
+
+**Files Created:**
+- `/mnt/workdisk/public_share/hakmem/core/box/smallobject_mid_v35_box.h` - Public API
+- `/mnt/workdisk/public_share/hakmem/core/smallobject_mid_v35.c` - Implementation
+
+**Implementation:**
+- TLS-cached page allocation (per-class fast path)
+- Slot sizes: C5=384B, C6=512B, C7=1024B
+- Page size: 64KB (170/128/64 slots for C5/C6/C7)
+- Alloc: Fast path (TLS cache hit) + Slow path (refill via ColdIface)
+- Free: Simplified counting (no freelist yet - deferred to v11b)
+- Header writing: Integrates with tiny_region_id_write_header
+
+**Key Design Decisions:**
+- Reused `SmallPageMeta` typedef (matches segment/cold_iface structure)
+- Simplified free path (cross-page free deferred to v11b RegionIdBox integration)
+- Header integration for compatibility with existing Tiny infrastructure
+
+### Task 3: Front Gate Integration (L0/L1 Boundary)
+
+**Files Modified:**
+- `/mnt/workdisk/public_share/hakmem/core/front/malloc_tiny_fast.h`
+
+**Changes:**
+1. Added MID v3.5 box header include
+2. Alloc path: Check policy for MID_V35, call `small_mid_v35_alloc()` before V7
+3. Free path: Check policy for MID_V35, call `small_mid_v35_free()` after ULTRA checks
+
+**Priority Order (Alloc/Free):**
+1. ULTRA (C4-C7)
+2. MID v3.5 (Policy-driven)
+3. V7 (Policy-driven)
+4. Legacy routes
+
+### Task 4: Build System Updates
+
+**Files Modified:**
+- `/mnt/workdisk/public_share/hakmem/Makefile`
+
+**Changes:**
+- Added `core/smallobject_mid_v35.o` to `OBJS_BASE`
+- Added `core/smallobject_mid_v35.o` to `BENCH_HAKMEM_OBJS_BASE`
+- Added `core/smallobject_mid_v35.o` to `TINY_BENCH_OBJS_BASE`
+
+**Build Results:**
+- Clean build successful
+- Benchmarks compiled: `bench_random_mixed_hakmem`, `bench_mid_large_mt_hakmem`
+- Minor warnings (unused parameter `size`) - non-critical
+
+## ENV Configuration
+
+### MID v3.5 Activation
+
+```bash
+# Enable MID v3.5
+export HAKMEM_MID_V35_ENABLED=1
+
+# Configure classes (default: 0x60 = C5+C6)
+export HAKMEM_MID_V35_CLASSES=0x60  # C5 + C6
+# export HAKMEM_MID_V35_CLASSES=0x20  # C5 only
+# export HAKMEM_MID_V35_CLASSES=0x40  # C6 only
+```
+
+### Policy Debug Output
+
+Policy initialization prints route assignments on first call:
+```
+[POLICY_V7_INIT] Route assignments:
+  C0: LEGACY
+  C1: LEGACY
+  C2: LEGACY
+  C3: LEGACY
+  C4: ULTRA
+  C5: MID_V35
+  C6: MID_V35
+  C7: ULTRA
+```
+
+## Next Steps (Task 5: A/B Benchmarks)
+
+### Benchmark 1: C6-Heavy (MID Specialization Check)
+
+```bash
+# Baseline: MID v3.5 OFF
+HAKMEM_PROFILE=C6_HEAVY_LEGACY_POOLV1 \
+HAKMEM_MID_V35_ENABLED=0 \
+./bench_mid_large_mt_hakmem 1 1000000 400 1
+
+# Test: MID v3.5 ON (C6 only)
+HAKMEM_PROFILE=C6_HEAVY_LEGACY_POOLV1 \
+HAKMEM_MID_V35_ENABLED=1 \
+HAKMEM_MID_V35_CLASSES=0x40 \
+./bench_mid_large_mt_hakmem 1 1000000 400 1
+```
+
+**Expected:** Performance within ±5% of MID v3
+
+### Benchmark 2: C5+C6-Only (257-768B Range)
+
+```bash
+# Baseline: MID v3.5 OFF
+HAKMEM_BENCH_MIN_SIZE=257 \
+HAKMEM_BENCH_MAX_SIZE=768 \
+HAKMEM_MID_V35_ENABLED=0 \
+./bench_random_mixed_hakmem 1000000 400 1
+
+# Test: MID v3.5 ON (C5+C6)
+HAKMEM_BENCH_MIN_SIZE=257 \
+HAKMEM_BENCH_MAX_SIZE=768 \
+HAKMEM_MID_V35_ENABLED=1 \
+HAKMEM_MID_V35_CLASSES=0x60 \
+./bench_random_mixed_hakmem 1000000 400 1
+```
+
+**Expected:** +2-4% improvement (matching v7 gains)
+
+### Benchmark 3: Mixed 16-1024B (Reference)
+
+```bash
+HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE \
+HAKMEM_MID_V35_ENABLED=1 \
+HAKMEM_MID_V35_CLASSES=0x60 \
+./bench_random_mixed_hakmem 1000000 400 1
+```
+
+**Expected:** Baseline ±3% (no regression)
+
+## Known Limitations (Deferred to v11b)
+
+1. **Cross-Page Free:** Current implementation only handles frees to the current TLS page
+   - Need RegionIdBox lookup for cross-page free
+   - Planned for v11b with proper segment ownership check
+
+2. **Freelist Reuse:** No freelist implementation yet
+   - Slots are marked free via counter only
+   - Full freelist support planned for v11b
+
+3. **Learner Route Switching:** Learner v2 is in observation mode only
+   - Dynamic route switching deferred to v11b
+   - Current implementation: static routing based on ENV
+
+## Code Quality
+
+- **Modularity:** Clean L1/L2/L3 separation maintained
+- **Box Boundaries:** Proper isolation between HotBox/ColdIface/Stats/Learner
+- **Header Compatibility:** Integrates with existing Tiny region_id infrastructure
+- **Build Hygiene:** All targets compile cleanly (only unused parameter warnings)
+
+## Files Summary
+
+### New Files (2)
+1. `core/box/smallobject_mid_v35_box.h` - Public API (48 lines)
+2. `core/smallobject_mid_v35.c` - Implementation (165 lines)
+
+### Modified Files (4)
+1. `core/box/smallobject_policy_v7_box.h` - Enum update
+2. `core/smallobject_policy_v7.c` - ENV helpers + priority logic
+3. `core/front/malloc_tiny_fast.h` - Route integration
+4. `Makefile` - Object file lists (3 locations)
+
+### Total Code Addition
+- **New:** ~213 lines
+- **Modified:** ~60 lines
+- **Total Impact:** ~273 lines
+
+## Architecture Notes
+
+### Layer Interaction (L0→L1→L2→L3)
+
+```
+L0 (Front)   malloc_tiny_fast.h
+               ↓ (Policy check: MID_V35?)
+L1 (HotBox)  smallobject_mid_v35.c
+               ↓ (Refill needed?)
+L2 (Cold)    smallobject_cold_iface_mid_v3.c
+               ↓ (Get page from segment)
+L2 (Segment) smallobject_segment_mid_v3.c
+               ↓ (Stats recording)
+L2 (Stats)   smallobject_stats_mid_v3.c
+               ↓ (Learner evaluation - observation only)
+L2 (Learner) smallobject_learner_v2.c
+               ↓ (Policy update - dormant)
+L3 (Policy)  smallobject_policy_v7.c
+```
+
+### Memory Layout
+
+- **Segment:** 2 MiB contiguous region
+- **Pages:** 64KB per page
+- **Slots:** 384B (C5), 512B (C6), 1024B (C7)
+- **TLS Cache:** One current page per class per thread
+
+## Conclusion
+
+Phase v11a-3 successfully activated MID v3.5 infrastructure. The implementation is ready for A/B benchmarking to validate performance against the original MID v3 and establish a baseline for future optimizations.
+
+**Status:** ✅ Build Complete
+**Next:** Task 5 (A/B Benchmarks) - Performance validation
+**Future:** Task 6 (Documentation) - Results recording