Task 4.3's multi-host merge itself was already implemented and verified
by task 4.2. The one unproven clause -- job-level shared-resource
allocation computed once regardless of host count -- is now covered by
test_shared_resource_debited_once_regardless_of_host_count, using a
PER_JOB (not PER_TASK) global resource so a per-bucket-repeated
computation can't coincidentally sum to the correct total. Mutation
testing (a deliberately injected duplicate per-host shared debit)
confirms the test fails exactly as expected; production code required
no change.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XYdtrEWWZfKRRGED7raEYg
Replace parjob's return-0 stub with a real multi-host allocator: for each
candidate plan, walk buckets in the given (descending) order, claiming a
distinct host per bucket via a fresh host_iter excluding hosts already
claimed elsewhere in the same plan attempt. On a bucket failure, reverse
every earlier successful claim's provisional debit via
sched_ctx_uncommit_host() before advancing to the next plan (Req 4.2, 4.4,
4.5, 4.6, 4.7).
Fix parjob_prepare_allocation() to compute each bucket's want from that
bucket's own slot count (ctx->nslots) instead of a fixed value, and reset
ctx->alloc_req.host at the top of each bucket's scan so host_iter's
pre-filter can't inherit a stale want from a differently-sized prior
bucket (safe: sched_try_alloc_on_host_() always repopulates it from the
real per-bucket want before its own authoritative check runs).
Add a maxTasks<=1 guard matching Req 4 AC1's precondition, needed because
a snapshot-restored job with unpopulated maxTasks==0 (pre-existing,
tracked separately as bug-1767) would otherwise reach parjob's now-real
allocator instead of being silently ignored as before.
On full success, merges every claimed bucket into one xce_job_alloc_t via
make_job_alloc()'s existing runtime-sized host array, satisfying task
4.3's multi-host commit scope as well.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XYdtrEWWZfKRRGED7raEYg
Add the real xce_alloc_plan_iter_t for parjob: for host-count k=1..maxTasks
(ascending, most-preferred-first), generate one balanced partition of
maxTasks into k buckets (floor/ceil split, remainder to the first rem
buckets), which is descending by construction. Pure function of maxTasks
alone -- never dereferences sched -- with a real pthread_testcancel()
cancellation point and stable post-exhaustion NULL (Req 2.1-2.6, 4.1).
my_alloc()/parjob_prepare_allocation() remain untouched stubs; wiring the
iterator into real allocation is task 4.2.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XYdtrEWWZfKRRGED7raEYg
