Wrap sched_make_primary_alloc_() -- the single choke point all three
primary-resreq shapes (standalone, compound-nested, alter-nested via
compound delegation) already funnel through -- with a cache lookup
before allocation and a cache insert on exhaustion. On a hit, pend the
job immediately via the same make_pendreason()/add_job_preason() path
every exhaustion case already uses, without invoking either allocator
(Req 7.3, 7.4, 7.5).
A nested primary has no real per-primary schedobj, so
sched_primary_cache_obj_() synthesizes one on the stack per dispatch for
cache-key purposes; verified memory-safe since alloc_cache.c's
build_key_() copies the fingerprint/identity by value synchronously
before the stack frame unwinds.
Log bug-1768 (compound/alter-nested primaries never get real slot/rusage
availability checks -- seqjob/parjob's prepare_allocation hooks no-op
whenever ctx->schedobj->tag != XCE_RESREQ_PRIMARY) and bug-1769
(sched_make_alter_allocation() type-confuses xce_compound_schedobj_t*
as xce_sched_obj_t*, a ~112-byte heap over-read, currently untested).
Both are pre-existing and out of this feature's scope; discovered and
confirmed while building this task's dispatch tests.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XYdtrEWWZfKRRGED7raEYg
Rongsong Shen
5c022d0b4f