Module: Evilution::Parallel::WorkQueue::WorkerRegistry

Defined in:
lib/evilution/parallel/work_queue/worker_registry.rb

Overview

Process-global registry of live worker process-group ids (pgids).

EV-jwao / GH #1332: EV-cnx8 made each Worker its own process-group leader so a stuck worker’s whole subtree can be group-killed. Side effect: a terminal Ctrl-C delivers SIGINT only to the parent’s foreground group, so workers (now in their own groups) no longer receive it – and the parent’s fatal-signal death skips work_queue#map’s ‘ensure cleanup_workers`, leaking any worker that was actively running a (possibly blocking) mutation at interrupt time.

Runner#install_signal_handler reads this registry from inside the trap and forwards INT/TERM to each worker group before re-raising to DEFAULT.

Signal-safety: under MRI a trap handler runs on the main thread between VM instructions, so it must not acquire a Mutex (the main thread may hold it -> deadlock). register/unregister therefore swap @pgids for a freshly built frozen array via a single atomic reference assignment (copy-on-write). The trap reads the current reference once and iterates that complete, immutable snapshot – no torn reads, no lock.

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.pgids ⇒ Object (readonly)

Frozen snapshot. Safe to read from a signal handler.



28
29
30
 
# File 'lib/evilution/parallel/work_queue/worker_registry.rb', line 28

def pgids
  @pgids
end

Class Method Details

.register(pgid) ⇒ Object 



30
31
32
 
# File 'lib/evilution/parallel/work_queue/worker_registry.rb', line 30

def register(pgid)
  @pgids = (@pgids + [pgid]).freeze
end

.signal_all(sig) ⇒ Object 



38
39
40
41
42
43
44
45
 
# File 'lib/evilution/parallel/work_queue/worker_registry.rb', line 38

def signal_all(sig)
  @pgids.each do |pgid|
    Process.kill(sig, -pgid)
  rescue Errno::ESRCH
    # Group already gone (worker + subtree reaped) -- nothing to signal.
    nil
  end
end

.unregister(pgid) ⇒ Object 



34
35
36
 
# File 'lib/evilution/parallel/work_queue/worker_registry.rb', line 34

def unregister(pgid)
  @pgids = @pgids.reject { |existing| existing == pgid }.freeze
end