Add H3 + H4 dealloc edge-case hooks and integration test (Phase 3.4) - #9
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- Install H3 heap-profile hook in Allocator::dealloc_remote on the SecondaryAllocator branch (catches GWP-ASan / non-snmalloc pointers that bypass the snmalloc-owned pagemap). - Install H4 heap-profile hook in Allocator::dealloc_remote_slow's lazy-init recursion lambda, immediately before the recursive a->dealloc(p). Pairs with H1 to keep the recursion-guard tight. - Both hooks live entirely under #ifdef SNMALLOC_PROFILE; default Config OFF build is byte-identical to Phase 3.3. - Both hooks reuse profile::record_dealloc<Config>; idempotence is guaranteed by the CAS in clear_profile_slot and the per-thread ReentrancyGuard. No new state machines, no new allocations on the free path. - New test: src/test/func/profile_h3_h4/profile_h3_h4.cc. Triple- and quadruple-clear idempotence, nullptr robustness, fresh-thread remote-free stress, default-Config compile-time no-op. - New test: src/test/func/profile_integration/profile_integration.cc. 16 threads x 100k allocs x varied size ladder, ~50/50 same-thread vs cross-thread free, plus a one-producer-many-consumers stress. Asserts sample count within 6 sigma of Poisson expectation, post-free leak <= documented tolerance (<= 1% + 4), and that the global SampledList drains to zero. Sampling rate (128 KiB) sized so expected samples stay well below the NodePool capacity ceiling. - Wires ticket 86ahrfx9g (multi-threaded alloc + cross-thread dealloc integration stress). - Observed teardown-straggler ratio improves from ~1/1250 in the Phase 3.3 8-thread e2e test to ~1/4000 in the new 16-thread integration test, a ~3x reduction.
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Summary
Phase 3.4 — closes dealloc-side coverage. Completes the milestone's H1–H4 hook set.
corealloc.h:1458—Allocator::dealloc_remoteSecondaryAllocator escape arm. Catches GWP-ASan / non-snmalloc pointers that bypass the snmalloc-owned pagemap.corealloc.h:1522—Allocator::dealloc_remote_slowlazy-init recursion lambda, immediately before recursivea->dealloc(p). Pairs with H1 for tight recursion-guard.#ifdef SNMALLOC_PROFILE. Default Config OFF build byte-identical to Phase 3.3.record_dealloc<Config>. Idempotence guaranteed byclear_profile_slotCAS +ReentrancyGuard. No new state machines.Test plan
SNMALLOC_PROFILE=OFFSNMALLOC_PROFILE=ONprofile_h3_h4: triple/quadruple-clear idempotence, nullptr robustness, fresh-thread remote-free stress, default-Config compile-time no-opprofile_integration(ticket 86ahrfx9g): 16 threads × 100k allocs × {16,64,256,1024} size ladder, ~50/50 same/cross-thread free + one-producer-many-consumers stressSampledListdrains to zeroTickets closed: 86ahzwj2f (H3 + H4), 86ahrfx9g (multi-threaded alloc + cross-thread dealloc integration)