Indexing broke on x86-64 Linux: the index worker refused to start and
SIGKILLed its own process group, so every venue reported nothing but
"index worker ended with killed (exit=-1, signal=9)".
glibc places a thread's static TLS block inside the stack allocation it
makes for that thread. This branch's new thread-local caches -- a
512-slot field cache (~24 KB), per-depth tree cursors (~4 KB) and two
parked CBMArenas (~8 KB; an arena carries blocks[256] + block_sizes[256])
-- took static TLS from 47,905 to 93,513 bytes. The 64 KB parent-death
watchdog thread then could not be created at all, and a worker without
process-tree containment correctly refuses to index.
Four layers, because there were four things wrong:
- The big thread-locals move to the heap behind a thread-local POINTER,
allocated once per thread and reused, each with a correct fallback if
allocation fails (the field cache and cursor pool are caches; a miss
is slower, never wrong). Static TLS is back to 52,233 bytes.
- PARENT_WATCHDOG_STACK_SIZE 64 KB -> 256 KB. "The watchdog only polls,
a tiny stack suffices" was true when written and false once TLS
reached ~50 KB, because the TLS block comes out of that same
allocation.
- cbm_thread_create retries with the default stack on EINVAL. A stack
size is a hint about what a thread needs; the platform refusing the
hint is not a reason to fail to create the thread.
- tests/test_thread_stack_tls_contract.sh (Step 5a of scripts/test.sh)
keeps static TLS a quarter clear of the smallest requested stack,
reading that smallest size from the sources so a new small stack
tightens the gate automatically.
Two diagnostics that made this findable at all, and that stay:
smoke-test.sh prints the worker log its failure message names (CI deletes
that sandbox with the job, so the one artifact naming the cause was
unreadable), and worker_containment_unavailable() now reports WHICH of
its conditions failed, with pid/pgrp/ppid.
Verified in the amd64 container, the venue nothing on the local ladder
covers: baseline main indexes 9039 nodes/15067 edges, this branch before
the fix refuses to start the worker, and after it indexes 9039/15067.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Answers a question the existing tooling could not: of everything we
allocate, how much is never used?
Lanes, all driven by scripts/memwaste.sh:
event every allocation observed through the memory core — size, age,
churn, and whether the bytes were ever written
access SanitizerCoverage load/store instrumentation, so "allocated and
never touched" is measured rather than inferred
scaling k vs 2k replicas through clang profile counters, to catch
super-linear work per file
padding allocator slack per size class
ratchet the numbers recorded per venue so a regression is visible
The event lane needed a foreign-free counter: on Windows the override sees
frees for blocks it never allocated (they come from the CRT), and counting
those as untracked tripped the soundness gate. mem_events now separates
them (14 daemon / 5 worker on the Go corpus).
Two portability fixes the lanes surfaced, both real:
- the enable decision must not be cached before `environ` exists. Under
-fsanitize-coverage the UBSan preinit runs dlsym -> malloc -> our
wrapper before glibc sets up environ, so the lane silently disabled
itself and produced no dump at all on Linux.
- the access map needs 48 bits: arm64 Linux hands out addresses above
2^47, which a 47-bit map dropped on the floor.
mem_profile is retired into this: it measured a strict subset and had its
own sampling story.
Local-only by decision — not a PR-CI gate. _memwaste.yml runs the lanes on
all three platforms report-only, and pr.yml/release.yml carry the wiring.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Martin Vogel