Replaces the 2b.1b shared-L2 capacity-miss SKIP with a deterministic
collective-free evict-to-fit, and deletes the #5 deadlock. This is the gate that
makes --enable-cp-shared-physical-l2-hicache safe in a real run.
evict-to-fit (_reserve_write_cp_shared_l2_evict_to_fit, hiradix): on a shared-L2
reserve capacity miss -- which raises identically on every CP rank over the
replicated free list -- snapshot the plannable shared-L2 host leaves (excluding
the node being backed up) in the replicated SLRU order (_cp_host_evict_key =
Phase-1 logical clock + node.id total-order tiebreak), release the coldest one at
a time (each a replicated free-list mutation via the proven
_evict_cp_host_for_write_admission teardown -> evict_cp_host -> allocator.release)
and retry the pooled reserve after each, stopping at the first fit.
Fragmentation-correct (free coalesces in _return_range). Identical victim
set + order + deterministic reserve => every rank evicts the same victims and
stops at the same point (design Thm 1), so NO collective is needed. The snapshot
is one-level by design (a parent promoted to a leaf mid-loop is not re-pushed;
deep cascades skip-and-retry next tick -- missed identically on all ranks).
Exhaustion -> loud rate-limited skip (transient: pinned/in-flight objects hold
the pool), never a hang.
#5 deadlock DELETED: stripped the synchronize_across_ranks all_reduce machinery
(the `while len(heap) and not all_ranks_done()` ReduceOp.MIN host_evict_done_min
closure + the param) from _evict_host_for_physical_slots -- never reached (no
caller passed True) and the headline CP-deadlock shape. evict_host(num_tokens)
still works (single-arg, equivalent non-sync loop).
Opus adversarial review = SHIP (all 7 findings PASS: determinism [_cp_host_evict_key
purely replicated, pin_expiry dormant under CP], teardown byte-equivalence + no
double-free, no infinite recursion + clean abort-on-partial, snapshot safety [no
ancestor/descendant among host leaves], bounded termination, clean #5 strip,
flag-off path untouched). Tests: new test_eight_ranks_evict_to_fit_stays_identical
(fill->miss->release-in-order->retry -> identical placement, exercises coalescing)
+ 88/88 pool suite (syh-dev-new) + import smoke.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
leavelet
07c2b9bc57