New alloc_runner.c: sched_allocator_run() validates its inputs (-EINVAL
without touching the pend reason), applies the plugin's optional accepts
guard, creates the pend-reason record, then checks shared resources: one
host-less NO_RESOURCE reason per unmet entry (skip only on vget < 0,
fixing bug-1893) and the met amounts counted once as uncommitted. Plan
search follows in task 3.2. Runner tests use a fake allocator contract;
the pend-reason factory audit now scans the runner.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Adds xce_core_go()/xce_core_end_session() (new core_session.c):
xce_core_go() is non-blocking, performs begin-session state reset
(select-eval-ctx, resval resets), signals the picker thread via wbuf,
and returns -EINVAL on a reentrant call while a session is already
active (proven a true no-op, not just an early return). Draining
core->decisions and invoking the driver's on_decision callback is the
driver's own responsibility between core_go() and core_end_session()
(confirmed driver-owned, not core-owned, per the Driver <-> Core
protocol). xce_core_set_decision_cb() registers the callback + driver
context as a separate setter, keeping xce_sched_core_init()'s live
sched_init() call site untouched. Adds XCE_DECISION_PREEMPT to
decision.h (jobid/victims[]/reason) alongside the existing DISPATCH/
PEND types. Additive only — sched_go/sched_begin_session/
sched_end_session/sched_allocator/main.c remain untouched.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019dw5WnN3DXStaEaPYfACU1
Splits xce_scheduler_t along the controller-I/O seam: xce_sched_core_t
(new core.h/core.c) now holds all scheduling state (jobs/queues/workers/
users/projects/resource managers/plugins/three-thread-cbuf pipeline),
while xce_scheduler_t shrinks to {core; apictx; cluster_cfg}. Proven via
an nm-based link-time isolation test (zero netio/xcecli/idgen/delaymgr
symbols reachable from core.c) plus a reproducible wall-clock-call guard.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019dw5WnN3DXStaEaPYfACU1
Closes out group 2 (Core: Builtin FCFS Picker). Confirms builtin_fcfs's
ordering matches legacy fcfs_elect_job (byte-identical comparators, same
sched_queue_is_ready/sched_job_is_ready gates, provably equivalent jobid
sequence), confirms tasks 1.1-2.5 left every pre-existing test file
unmodified, and confirms resreq immutability, pend-reason factory-only
allocation, and select_eval_ctx_t memoization all hold across every file
this spec has touched so far. Adds a durable regression lock for the
pend-reason factory invariant (no direct calloc(pendreason_t) outside
make_pendreason()).
