Lwt_preemptive better name for worker termination

raphael-proust · raphael-proust · commit 75ba144771f6 · 2025-09-19T13:27:27.000+02:00
diff --git a/src/unix/lwt_preemptive.ml b/src/unix/lwt_preemptive.ml
@@ -276,5 +276,5 @@ let run_in_domain_dont_wait d f handler =
   let f () = Lwt.catch f (fun exc -> handler exc; Lwt.return_unit) in
   run_in_domain_dont_wait d f
 
-let kill_all () =
+let terminate_worker_threads () =
   Queue.iter (fun thread -> CELL.kill thread.task_cell) (Domain.DLS.get workers)
diff --git a/src/unix/lwt_preemptive.mli b/src/unix/lwt_preemptive.mli
@@ -83,11 +83,18 @@ val get_max_number_of_threads_queued : unit -> int
   (** Returns the size of the waiting queue, if no more threads are
       available *)
 
+val terminate_worker_threads : unit -> unit
+(* [terminate_worker_threads ()] queues up a message for all the workers of the
+   calling domain to self-terminate. This causes all the workers to terminate
+   after their current jobs are done which causes the threads of these workers
+   to end.
+
+   Terminating the threads attached to a domain is necessary for joining the
+   domain. Thus, if you use-case for domains includes spawning and joining them,
+   you must call [terminate_worker_threads] just before calling
+   [Domain.join]. *)
+
 (**/**)
 val nbthreads : unit -> int
 val nbthreadsbusy : unit -> int
 val nbthreadsqueued : unit -> int
-
-(* kill_all is to be called before joining the domain, not satisfying UI for
-   now, searching for a better way *)
-val kill_all : unit -> unit
diff --git a/test/multidomain/preempting.ml b/test/multidomain/preempting.ml
@@ -21,7 +21,7 @@ let domain_go_brrrrrrr input = Domain.spawn (fun () ->
       Lwt_list.map_p (Lwt_preemptive.detach simulate_work) input
     )
   in
-  Lwt_preemptive.kill_all ();
+  Lwt_preemptive.terminate_worker_threads ();
   v
 )
 

Original file line number	Diff line number	Diff line change
`@@ -21,7 +21,7 @@ let domain_go_brrrrrrr input = Domain.spawn (fun () ->`
`21`	`21`	`Lwt_list.map_p (Lwt_preemptive.detach simulate_work) input`
`22`	`22`	`)`
`23`	`23`	`in`
`24`		`- Lwt_preemptive.kill_all ();`
	`24`	`+ Lwt_preemptive.terminate_worker_threads ();`
`25`	`25`	`v`
`26`	`26`	`)`
`27`	`27`