--concurrent-marking and --parallel-marking don't work and disabled by default

[MGorkov]

Version

v16.13.0

Platform

Linux dev 4.18.0-305.el8.x86_64 #1 SMP Thu Apr 29 08:54:30 EDT 2021 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

No response

What steps will reproduce the bug?

node --concurrent-marking
node --parallel-marking
node --concurrent-marking --parallel-marking

How often does it reproduce? Is there a required condition?

always

What is the expected behavior?

node runs without error

What do you see instead?

Fatal error in , line 0
Check failed: !FLAG_concurrent_marking && !FLAG_parallel_marking.

FailureMessage Object: 0x7ffeda8b29f0
1: 0xb6f151 [node]
2: 0x1bf56f4 V8_Fatal(char const*, ...) [node]
3: 0xe603ad [node]
4: 0xeb31ae v8::internal::Heap::SetUp() [node]
5: 0xe3cd6b v8::internal::Isolate::Init(v8::internal::SnapshotData*, v8::internal::SnapshotData*, bool) [node]
6: 0x124af66 [node]
7: 0xd1314e v8::Isolate::Initialize(v8::Isolate*, v8::Isolate::CreateParams const&) [node]
8: 0xb4451c node::NodeMainInstance::NodeMainInstance(v8::Isolate::CreateParams*, uv_loop_s*, node::MultiIsolatePlatform*, std::vector<std::string, std::allocatorstd::string > const&, std::vector<std::string, std::allocatorstd::string > const&, std::vector<unsigned long, std::allocator > const*) [node]
9: 0xac67d3 node::Start(int, char**) [node]
10: 0x7fe2a3721493 __libc_start_main [/lib64/libc.so.6]
11: 0xa3bfbc [node]

Additional information

these options are disabled by default:
node --v8-options | grep -A1 -E '(--parallel-marking|--concurrent-marking)'

--concurrent-marking (use concurrent marking)
type: bool default: false
--parallel-marking (use parallel marking in atomic pause)
type: bool default: false

[targos]

Concurrent marking is not enabled in Node.js builds. Let's ask @nodejs/v8 if it's something stable enough that we should enable it. If yes, since which V8 version?

[victorgomes]

@mlippautz

[MGorkov]

Concurrent marking is not enabled in Node.js builds. Let's ask @nodejs/v8 if it's something stable enough that we should enable it. If yes, since which V8 version?

It is unstable only in new v9.* versions? It looks like everything was fine in the previous nodejs version, with old V8

[targos]

Refs: v8/v8@acf5e1a

The issue is that the v8_enable_atomic_object_field_writes and v8_enable_atomic_marking_state compile options were not ported to Node.js, so they end up being both disabled. Should we enable them? @ulan

[ulan]

@targos: yes, please go ahead with enabling them in Node. Both v8_enable_atomic_object_field_writes and v8_enable_atomic_marking_state are safe and intended to be enabled by default. Sorry for breaking Node, I thought the build rules are generated automatically from V8's GN.

[mlippautz]

Hey @ulan :)

Yes, it's safe to enable and the concurrent/parallel marking just moved behind those flags.