Blocking processes / scheduler #80
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thats it :P
…process completes
| (* Override the handle exit function *) | ||
| (* let handle_exit_blocking_proc pool sch proc reason = *) | ||
| (* Scheduler.handle_exit_proc pool sch.scheduler proc reason; *) | ||
| (* remove_from_pool pool sch *) |
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I was thinking I could somehow have a custom handle_exit function but just having the domain doesnt mean I can shutdown and remove the scheduler I think, because I really need to close it from inside the run + run_loop scheduler loop, therefore I commented out this code here.
Would this still work if I had a way of shutting down a scheduler from outside that loop? Presumably this handle_exit_blocking is running from inside the Domain so could I just raise an exception here instead of the bool flags approach?
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| let pp_flag fmt t = | ||
| match t with | ||
| | Trap_exit b -> Format.fprintf fmt "trap_exit <- %b" b | ||
| | Priority p -> Format.fprintf fmt "priority <- %s" (P.priority_to_string p) | ||
| | _ -> failwith "TODO" |
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will fix this once we're happy with the other code
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| Exception exn) | ||
| in | ||
| Process.set_flag proc (IsBlockingProc true); |
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By adding the IsBlockingProc flag here we're basically saying "when this processes exits, we can go ahead and shutdown the scheduler".
The main thought process here is I don't want to modify the raw Process and Scheduler code too much making a bunch of duplicated functions; I'd rather share as much of the code that currently exists.
I struggled to figure out how to do this shutdown of a blocking scheduler when the process finishes from the scheduler's point of view rather than the process's, as there's no way to distinguish a Blocking_scheduler.t from a Scheduler.t in the run and run_loop code for the reason above - wanting to keep all the code accepting Scheduler.t the same without duplicating it. Hence the mutable stop : bool
| @@ -26,12 +27,15 @@ type io = { | |||
| mutable calls_send : int; | |||
| } | |||
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| type blocking = { scheduler : t; domain : unit Domain.t } | |||
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Potentially we don't need this type but when you said
new Blocking_scheduler that wraps a Scheduler and adds logic for removing the domains from the blocking_processes domain list
I'm not 100% sure in OCaml what the best way of having a "wrapping" type is without having say a Scheduler trait like in Rust i.e. adhoc polymorphism. Is this type + the Blocking_scheduler a good way of doing this do you think?
(I'm actually not sure we technically need to keep a list. Does the domain live as long as its function body i.e. as long as the Scheduler's loop? If we shut the scheduler down the Domain should be closed/freed/whatever you call it automatically if that were the case I think. But it's probably still nice to have a typed record for this and keep that data around in case we need to add to it later)
Addresses #67 (a first pass at least)