info limit was correctly implemented and tested but inert against a real
replay: register_limit()'s only call site was normal-mode sched_register_
plugins(); sim mode's own plugin bootstrap (sim_bootstrap_picker()) never
registered the limit plugin. The snapshot format already carries the
original session's limit config (sim->core.config, a borrowed reference set
by xce_sched_core_load_snapshot()) -- nothing needed to change in the
recording/replay format.
New sim_bootstrap_limit_plugin() (sim_limit.c, mirroring sim_picker.c's
structure) registers the plugin via plugin_register_core() and seeds it via
a new limit_seed_config(plugin, xce_sched_core_t* core, config) entry point,
wired into sim_loop.c alongside the existing sim_bootstrap_picker() call.
limit_new_plugin() extracted from register_limit() as a factory, mirroring
builtin_fcfs_new_plugin()'s established pattern; register_limit() itself is
behavior-preserving.
First attempt set plugin->sched to a disguised xce_sched_sim_driver_t*,
relying on it sharing xce_scheduler_t's first-member layout to reuse the
existing config_hook path -- rejected on review: this repeats the exact
cross-cast pattern that already corrupted memory once in this codebase (see
core.h's xce_core_cache_clear_cb_t history). Fixed by making
limit_seed_config() take xce_sched_core_t* as an honest parameter instead,
with limit_update_config() (normal mode) and the new sim path both
delegating to a shared limit_seed_config_impl() -- no cast, no aliasing risk,
independently verified by two review rounds reading the actual struct
layouts and call chains.
Also added sim_limit.c to sched_sim_isolation_lib so Req 5 AC 17's
controller-I/O-isolation check covers it (an initial gap, closed in the same
remediation round). Two ripple waves of the same established link-stub
pattern applied to the ~24 white-box test files that #include sim_loop.c.
info limit now shows real configured-limit data against a genuine replay.
Live usage will still correctly show "no active usage instance yet" until a
separate, larger fix (logged as bug-1826) wires limit *matching* into the
sim decision path -- deliberately out of this task's scope.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLSNJhNoULvVcUhXEFafQC
Rongsong Shen
487e7b9419