diff options
Diffstat (limited to 'erts/preloaded/src/erts_code_purger.erl')
| -rw-r--r-- | erts/preloaded/src/erts_code_purger.erl | 396 |
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. + |