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-rw-r--r--erts/preloaded/src/erts_code_purger.erl396
1 files changed, 237 insertions, 159 deletions
diff --git a/erts/preloaded/src/erts_code_purger.erl b/erts/preloaded/src/erts_code_purger.erl
index d1e64342e0..fd214228c7 100644
--- a/erts/preloaded/src/erts_code_purger.erl
+++ b/erts/preloaded/src/erts_code_purger.erl
@@ -22,28 +22,72 @@
%% Purpose : Implement system process erts_code_purger
%% to handle code module purging.
--export([start/0, purge/1, soft_purge/1]).
+-export([start/0, purge/1, soft_purge/1, pending_purge_lambda/3,
+ finish_after_on_load/2]).
-spec start() -> term().
start() ->
register(erts_code_purger, self()),
process_flag(trap_exit, true),
- loop().
-
-loop() ->
- _ = receive
- {purge,Mod,From,Ref} when is_atom(Mod), is_pid(From) ->
- Res = do_purge(Mod),
- From ! {reply, purge, Res, Ref};
-
- {soft_purge,Mod,From,Ref} when is_atom(Mod), is_pid(From) ->
- Res = do_soft_purge(Mod),
- From ! {reply, soft_purge, Res, Ref};
-
- _Other -> ignore
- end,
- loop().
+ wait_for_request().
+
+wait_for_request() ->
+ handle_request(receive Msg -> Msg end, []).
+
+handle_request({purge, Mod, From, Ref}, Reqs) when is_atom(Mod), is_pid(From) ->
+ {Res, NewReqs} = do_purge(Mod, Reqs),
+ From ! {reply, purge, Res, Ref},
+ check_requests(NewReqs);
+handle_request({soft_purge, Mod, From, Ref}, Reqs) when is_atom(Mod), is_pid(From) ->
+ {Res, NewReqs} = do_soft_purge(Mod, Reqs),
+ From ! {reply, soft_purge, Res, Ref},
+ check_requests(NewReqs);
+handle_request({finish_after_on_load, {Mod,Keep}, From, Ref}, Reqs)
+ when is_atom(Mod), is_boolean(Keep), is_pid(From) ->
+ NewReqs = do_finish_after_on_load(Mod, Keep, Reqs),
+ From ! {reply, finish_after_on_load, ok, Ref},
+ check_requests(NewReqs);
+handle_request({test_purge, Mod, From, Type, Ref}, Reqs) when is_atom(Mod), is_pid(From) ->
+ NewReqs = do_test_purge(Mod, From, Type, Ref, Reqs),
+ check_requests(NewReqs);
+handle_request(_Garbage, Reqs) ->
+ check_requests(Reqs).
+
+check_requests([]) ->
+ wait_for_request();
+check_requests([R|Rs]) ->
+ handle_request(R, Rs).
+%%
+%% Processes that tries to call a fun that belongs to
+%% a module that currently is being purged will end
+%% up here (pending_purge_lambda) in a suspended state.
+%% When the purge operation completes or aborts (soft
+%% purge that failed) these processes will be resumed.
+%%
+pending_purge_lambda(_Module, Fun, Args) ->
+ %%
+ %% When the process is resumed, the following
+ %% scenarios exist:
+ %% * The code that the fun refers to is still
+ %% there due to a failed soft purge. The
+ %% call to the fun will succeed via apply/2.
+ %% * The code was purged, and a current version
+ %% of the module is loaded which does not
+ %% contain this fun. The call will result
+ %% in an exception being raised.
+ %% * The code was purged, and no current
+ %% version of the module is loaded. An attempt
+ %% to load the module (via the error_handler)
+ %% will be made. This may or may not succeed.
+ %% If the module is loaded, it may or may
+ %% not contain the fun. The call will
+ %% succeed if the error_handler was able
+ %% to load the module and loaded module
+ %% contains this fun; otherwise, an exception
+ %% will be raised.
+ %%
+ apply(Fun, Args).
%% purge(Module)
%% Kill all processes running code from *old* Module, and then purge the
@@ -60,16 +104,15 @@ purge(Mod) when is_atom(Mod) ->
Result
end.
-
-do_purge(Mod) ->
- case erts_internal:copy_literals(Mod, true) of
- false ->
- {false, false};
- true ->
- DidKill = check_proc_code(erlang:processes(), Mod, true),
- true = erts_internal:copy_literals(Mod, false),
- WasPurged = erts_internal:purge_module(Mod),
- {WasPurged, DidKill}
+do_purge(Mod, Reqs) ->
+ case erts_internal:purge_module(Mod, prepare) of
+ false ->
+ {{false, false}, Reqs};
+ true ->
+ {DidKill, NewReqs} = check_proc_code(erlang:processes(),
+ Mod, true, Reqs),
+ true = erts_internal:purge_module(Mod, complete),
+ {{true, DidKill}, NewReqs}
end.
%% soft_purge(Module)
@@ -85,179 +128,152 @@ soft_purge(Mod) ->
Result
end.
-
-do_soft_purge(Mod) ->
- case erts_internal:copy_literals(Mod, true) of
+do_soft_purge(Mod, Reqs) ->
+ case erts_internal:purge_module(Mod, prepare) of
false ->
- true;
+ {true, Reqs};
true ->
- DoPurge = check_proc_code(erlang:processes(), Mod, false),
- true = erts_internal:copy_literals(Mod, false),
- case DoPurge of
+ {PurgeOp, NewReqs} = check_proc_code(erlang:processes(),
+ Mod, false, Reqs),
+ {erts_internal:purge_module(Mod, PurgeOp), NewReqs}
+ end.
+
+%% finish_after_on_load(Module, Keep)
+%% Finish after running on_load function. If Keep is false,
+%% purge the code for the on_load function.
+
+finish_after_on_load(Mod, Keep) ->
+ Ref = make_ref(),
+ erts_code_purger ! {finish_after_on_load, {Mod,Keep}, self(), Ref},
+ receive
+ {reply, finish_after_on_load, Result, Ref} ->
+ Result
+ end.
+
+do_finish_after_on_load(Mod, Keep, Reqs) ->
+ erlang:finish_after_on_load(Mod, Keep),
+ case Keep of
+ true ->
+ Reqs;
+ false ->
+ case erts_internal:purge_module(Mod, prepare_on_load) of
false ->
- false;
+ Reqs;
true ->
- erts_internal:purge_module(Mod),
- true
+ {_DidKill, NewReqs} =
+ check_proc_code(erlang:processes(),
+ Mod, true, Reqs),
+ true = erts_internal:purge_module(Mod, complete),
+ NewReqs
end
end.
+
%%
-%% check_proc_code(Pids, Mod, Hard) - Send asynchronous
+%% check_proc_code(Pids, Mod, Hard, Preqs) - Send asynchronous
%% requests to all processes to perform a check_process_code
%% operation. Each process will check their own state and
%% reply with the result. If 'Hard' equals
%% - true, processes that refer 'Mod' will be killed. If
%% any processes were killed true is returned; otherwise,
%% false.
-%% - false, and any processes refer 'Mod', false will
-%% returned; otherwise, true.
-%%
-%% Requests will be sent to all processes identified by
-%% Pids at once, but without allowing GC to be performed.
-%% Check process code operations that are aborted due to
-%% GC need, will be restarted allowing GC. However, only
-%% ?MAX_CPC_GC_PROCS outstanding operation allowing GC at
-%% a time will be allowed. This in order not to blow up
-%% memory wise.
+%% - false, and any processes refer 'Mod', 'abort' will
+%% be returned; otherwise, 'complete'.
%%
-%% We also only allow ?MAX_CPC_NO_OUTSTANDING_KILLS
+%% We only allow ?MAX_CPC_NO_OUTSTANDING_KILLS
%% outstanding kills. This both in order to avoid flooding
%% our message queue with 'DOWN' messages and limiting the
%% amount of memory used to keep references to all
%% outstanding kills.
%%
-%% We maybe should allow more than two outstanding
-%% GC requests, but for now we play it safe...
--define(MAX_CPC_GC_PROCS, 2).
-define(MAX_CPC_NO_OUTSTANDING_KILLS, 10).
--record(cpc_static, {hard, module, tag}).
+-record(cpc_static, {hard, module, tag, purge_requests}).
-record(cpc_kill, {outstanding = [],
no_outstanding = 0,
waiting = [],
killed = false}).
-check_proc_code(Pids, Mod, Hard) ->
+check_proc_code(Pids, Mod, Hard, PReqs) ->
Tag = erlang:make_ref(),
CpcS = #cpc_static{hard = Hard,
module = Mod,
- tag = Tag},
- check_proc_code(CpcS, cpc_init(CpcS, Pids, 0), 0, [], #cpc_kill{}, true).
-
-check_proc_code(#cpc_static{hard = true}, 0, 0, [],
- #cpc_kill{outstanding = [], waiting = [], killed = Killed},
- true) ->
- %% No outstanding requests. We did a hard check, so result is whether or
- %% not we killed any processes...
- Killed;
-check_proc_code(#cpc_static{hard = false}, 0, 0, [], _KillState, Success) ->
- %% No outstanding requests and we did a soft check...
- Success;
-check_proc_code(#cpc_static{hard = false, tag = Tag} = CpcS, NoReq0, NoGcReq0,
- [], _KillState, false) ->
- %% Failed soft check; just cleanup the remaining replies corresponding
- %% to the requests we've sent...
- {NoReq1, NoGcReq1} = receive
- {check_process_code, {Tag, _P, GC}, _Res} ->
- case GC of
- false -> {NoReq0-1, NoGcReq0};
- true -> {NoReq0, NoGcReq0-1}
- end
- end,
- check_proc_code(CpcS, NoReq1, NoGcReq1, [], _KillState, false);
-check_proc_code(#cpc_static{tag = Tag} = CpcS, NoReq0, NoGcReq0, NeedGC0,
- KillState0, Success) ->
-
- %% Check if we should request a GC operation
- {NoGcReq1, NeedGC1} = case NoGcReq0 < ?MAX_CPC_GC_PROCS of
- GcOpAllowed when GcOpAllowed == false;
- NeedGC0 == [] ->
- {NoGcReq0, NeedGC0};
- _ ->
- {NoGcReq0+1, cpc_request_gc(CpcS,NeedGC0)}
- end,
-
- %% Wait for a cpc reply or 'DOWN' message
- {NoReq1, NoGcReq2, Pid, Result, KillState1} = cpc_recv(Tag,
- NoReq0,
- NoGcReq1,
- KillState0),
-
- %% Check the result of the reply
- case Result of
- aborted ->
- %% Operation aborted due to the need to GC in order to
- %% determine if the process is referring the module.
- %% Schedule the operation for restart allowing GC...
- check_proc_code(CpcS, NoReq1, NoGcReq2, [Pid|NeedGC1], KillState1,
- Success);
- false ->
+ tag = Tag,
+ purge_requests = PReqs},
+ cpc_receive(CpcS, cpc_init(CpcS, Pids, 0), #cpc_kill{}, []).
+
+cpc_receive(#cpc_static{hard = true} = CpcS,
+ 0,
+ #cpc_kill{outstanding = [], waiting = [], killed = Killed},
+ PReqs) ->
+ %% No outstanding cpc requests. We did a hard check, so result is
+ %% whether or not we killed any processes...
+ cpc_result(CpcS, PReqs, Killed);
+cpc_receive(#cpc_static{hard = false} = CpcS, 0, _KillState, PReqs) ->
+ %% No outstanding cpc requests and we did a soft check that succeeded...
+ cpc_result(CpcS, PReqs, complete);
+cpc_receive(#cpc_static{tag = Tag} = CpcS, NoReq, KillState0, PReqs) ->
+ receive
+ {check_process_code, {Tag, _Pid}, false} ->
%% Process not referring the module; done with this process...
- check_proc_code(CpcS, NoReq1, NoGcReq2, NeedGC1, KillState1,
- Success);
- true ->
+ cpc_receive(CpcS, NoReq-1, KillState0, PReqs);
+ {check_process_code, {Tag, Pid}, true} ->
%% Process referring the module...
case CpcS#cpc_static.hard of
false ->
%% ... and soft check. The whole operation failed so
- %% no point continuing; clean up and fail...
- check_proc_code(CpcS, NoReq1, NoGcReq2, [], KillState1,
- false);
+ %% no point continuing; fail straight away. Garbage
+ %% messages from this session will be ignored
+ %% by following sessions...
+ cpc_result(CpcS, PReqs, abort);
true ->
%% ... and hard check; schedule kill of it...
- check_proc_code(CpcS, NoReq1, NoGcReq2, NeedGC1,
- cpc_sched_kill(Pid, KillState1), Success)
+ KillState1 = cpc_sched_kill(Pid, KillState0),
+ cpc_receive(CpcS, NoReq-1, KillState1, PReqs)
end;
- 'DOWN' ->
- %% Handled 'DOWN' message
- check_proc_code(CpcS, NoReq1, NoGcReq2, NeedGC1,
- KillState1, Success)
+ {'DOWN', MonRef, process, _, _} ->
+ KillState1 = cpc_handle_down(MonRef, KillState0),
+ cpc_receive(CpcS, NoReq, KillState1, PReqs);
+ PReq when element(1, PReq) == purge;
+ element(1, PReq) == soft_purge;
+ element(1, PReq) == test_purge ->
+ %% A new purge request; save it until later...
+ cpc_receive(CpcS, NoReq, KillState0, [PReq | PReqs]);
+ _Garbage ->
+ %% Garbage message; ignore it...
+ cpc_receive(CpcS, NoReq, KillState0, PReqs)
end.
-cpc_recv(Tag, NoReq, NoGcReq, #cpc_kill{outstanding = []} = KillState) ->
- receive
- {check_process_code, {Tag, Pid, GC}, Res} ->
- cpc_handle_cpc(NoReq, NoGcReq, GC, Pid, Res, KillState)
- end;
-cpc_recv(Tag, NoReq, NoGcReq,
- #cpc_kill{outstanding = [R0, R1, R2, R3, R4 | _]} = KillState) ->
- receive
- {'DOWN', R, process, _, _} when R == R0;
- R == R1;
- R == R2;
- R == R3;
- R == R4 ->
- cpc_handle_down(NoReq, NoGcReq, R, KillState);
- {check_process_code, {Tag, Pid, GC}, Res} ->
- cpc_handle_cpc(NoReq, NoGcReq, GC, Pid, Res, KillState)
- end;
-cpc_recv(Tag, NoReq, NoGcReq, #cpc_kill{outstanding = [R|_]} = KillState) ->
- receive
- {'DOWN', R, process, _, _} ->
- cpc_handle_down(NoReq, NoGcReq, R, KillState);
- {check_process_code, {Tag, Pid, GC}, Res} ->
- cpc_handle_cpc(NoReq, NoGcReq, GC, Pid, Res, KillState)
+cpc_result(#cpc_static{purge_requests = PReqs}, NewPReqs, Res) ->
+ {Res, PReqs ++ cpc_reverse(NewPReqs)}.
+
+cpc_reverse([_] = L) -> L;
+cpc_reverse(Xs) -> cpc_reverse(Xs, []).
+
+cpc_reverse([], Ys) -> Ys;
+cpc_reverse([X|Xs], Ys) -> cpc_reverse(Xs, [X|Ys]).
+
+cpc_handle_down(R, #cpc_kill{outstanding = Rs,
+ no_outstanding = N} = KillState0) ->
+ try
+ NewOutst = cpc_list_rm(R, Rs),
+ KillState1 = KillState0#cpc_kill{outstanding = NewOutst,
+ no_outstanding = N-1},
+ cpc_sched_kill_waiting(KillState1)
+ catch
+ throw : undefined -> %% Triggered by garbage message...
+ KillState0
end.
-cpc_handle_down(NoReq, NoGcReq, R, #cpc_kill{outstanding = Rs,
- no_outstanding = N} = KillState) ->
- {NoReq, NoGcReq, undefined, 'DOWN',
- cpc_sched_kill_waiting(KillState#cpc_kill{outstanding = cpc_list_rm(R, Rs),
- no_outstanding = N-1})}.
-
+cpc_list_rm(_R, []) ->
+ throw(undefined);
cpc_list_rm(R, [R|Rs]) ->
Rs;
cpc_list_rm(R0, [R1|Rs]) ->
[R1|cpc_list_rm(R0, Rs)].
-cpc_handle_cpc(NoReq, NoGcReq, false, Pid, Res, KillState) ->
- {NoReq-1, NoGcReq, Pid, Res, KillState};
-cpc_handle_cpc(NoReq, NoGcReq, true, Pid, Res, KillState) ->
- {NoReq, NoGcReq-1, Pid, Res, KillState}.
-
cpc_sched_kill_waiting(#cpc_kill{waiting = []} = KillState) ->
KillState;
cpc_sched_kill_waiting(#cpc_kill{outstanding = Rs,
@@ -281,19 +297,81 @@ cpc_sched_kill(Pid,
no_outstanding = N+1,
killed = true}.
-cpc_request(#cpc_static{tag = Tag, module = Mod}, Pid, AllowGc) ->
- erts_internal:check_process_code(Pid, Mod, [{async, {Tag, Pid, AllowGc}},
- {allow_gc, AllowGc},
- {copy_literals, true}]).
-
-cpc_request_gc(CpcS, [Pid|Pids]) ->
- cpc_request(CpcS, Pid, true),
- Pids.
+cpc_request(#cpc_static{tag = Tag, module = Mod}, Pid) ->
+ erts_internal:check_process_code(Pid, Mod, [{async, {Tag, Pid}}]).
cpc_init(_CpcS, [], NoReqs) ->
NoReqs;
cpc_init(CpcS, [Pid|Pids], NoReqs) ->
- cpc_request(CpcS, Pid, false),
+ cpc_request(CpcS, Pid),
cpc_init(CpcS, Pids, NoReqs+1).
% end of check_proc_code() implementation.
+
+%%
+%% FOR TESTING ONLY
+%%
+%% do_test_purge() is for testing only. The purge is done
+%% as usual, but the tester can control when to enter the
+%% specific phases.
+%%
+do_test_purge(Mod, From, true, Ref, Reqs) ->
+ {Res, NewReqs} = do_test_hard_purge(Mod, From, Ref, Reqs),
+ From ! {test_purge, Res, Ref},
+ NewReqs;
+do_test_purge(Mod, From, false, Ref, Reqs) ->
+ {Res, NewReqs} = do_test_soft_purge(Mod, From, Ref, Reqs),
+ From ! {test_purge, Res, Ref},
+ NewReqs;
+do_test_purge(_, _, _, _, Reqs) ->
+ Reqs.
+
+do_test_soft_purge(Mod, From, Ref, Reqs) ->
+ PrepRes = erts_internal:purge_module(Mod, prepare),
+ TestRes = test_progress(started, From, Ref, ok),
+ case PrepRes of
+ false ->
+ _ = test_progress(continued, From, Ref, TestRes),
+ {true, Reqs};
+ true ->
+ {PurgeOp, NewReqs} = check_proc_code(erlang:processes(),
+ Mod, false, Reqs),
+ _ = test_progress(continued, From, Ref, TestRes),
+ {erts_internal:purge_module(Mod, PurgeOp), NewReqs}
+ end.
+
+do_test_hard_purge(Mod, From, Ref, Reqs) ->
+ PrepRes = erts_internal:purge_module(Mod, prepare),
+ TestRes = test_progress(started, From, Ref, ok),
+ case PrepRes of
+ false ->
+ _ = test_progress(continued, From, Ref, TestRes),
+ {{false, false}, Reqs};
+ true ->
+ {DidKill, NewReqs} = check_proc_code(erlang:processes(),
+ Mod, true, Reqs),
+ _ = test_progress(continued, From, Ref, TestRes),
+ true = erts_internal:purge_module(Mod, complete),
+ {{true, DidKill}, NewReqs}
+ end.
+
+test_progress(_State, _From, _Ref, died) ->
+ %% Test process died; continue so we wont
+ %% leave the system in an inconsistent
+ %% state...
+ died;
+test_progress(started, From, Ref, ok) ->
+ From ! {started, Ref},
+ Mon = erlang:monitor(process, From),
+ receive
+ {'DOWN', Mon, process, From, _} -> died;
+ {continue, Ref} -> erlang:demonitor(Mon, [flush]), ok
+ end;
+test_progress(continued, From, Ref, ok) ->
+ From ! {continued, Ref},
+ Mon = erlang:monitor(process, From),
+ receive
+ {'DOWN', Mon, process, From, _} -> died;
+ {complete, Ref} -> erlang:demonitor(Mon, [flush]), ok
+ end.
+