diff options
Diffstat (limited to 'erts/preloaded/src/erts_code_purger.erl')
| -rw-r--r-- | erts/preloaded/src/erts_code_purger.erl | 184 |
1 files changed, 120 insertions, 64 deletions
diff --git a/erts/preloaded/src/erts_code_purger.erl b/erts/preloaded/src/erts_code_purger.erl index f9208624b7..ee4fcedd2d 100644 --- a/erts/preloaded/src/erts_code_purger.erl +++ b/erts/preloaded/src/erts_code_purger.erl @@ -22,42 +22,13 @@ %% 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]). -spec start() -> term(). start() -> register(erts_code_purger, self()), process_flag(trap_exit, true), - try - %% Pass bad arguments to copy_literals() in - %% order to determine purge strategy used - %% by the VM... - Res = erts_internal:copy_literals(4711, badarg), - exit({copy_literals_returned, Res}) - catch - error : badarg -> %% VM use old purge strategy - old_loop(); - error : notsup -> %% VM use new purge strategy - loop(); - Type : Reason -> - %% This should not be possible... - exit({"Unexpected copy_literals() behaviour", - {Type, Reason}}) - end. - -old_loop() -> - _ = receive - {purge,Mod,From,Ref} when is_atom(Mod), is_pid(From) -> - Res = do_old_purge(Mod), - From ! {reply, purge, Res, Ref}; - - {soft_purge,Mod,From,Ref} when is_atom(Mod), is_pid(From) -> - Res = do_old_soft_purge(Mod), - From ! {reply, soft_purge, Res, Ref}; - - _Other -> ignore - end, - old_loop(). + loop(). loop() -> _ = receive @@ -69,10 +40,43 @@ loop() -> Res = do_soft_purge(Mod), From ! {reply, soft_purge, Res, Ref}; + {test_purge, Mod, From, Type, Ref} when is_atom(Mod), is_pid(From) -> + do_test_purge(Mod, From, Type, Ref); + _Other -> ignore end, loop(). +%% +%% 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 @@ -89,22 +93,15 @@ purge(Mod) when is_atom(Mod) -> Result end. - -do_old_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} - end. - do_purge(Mod) -> - DidKill = check_proc_code(erlang:processes(), Mod, true), - WasPurged = erts_internal:purge_module(Mod), - {WasPurged, DidKill}. + case erts_internal:purge_module(Mod, prepare) of + false -> + {false, false}; + true -> + DidKill = check_proc_code(erlang:processes(), Mod, true), + true = erts_internal:purge_module(Mod, complete), + {true, DidKill} + end. %% soft_purge(Module) %% Purge old code only if no procs remain that run old code. @@ -119,27 +116,17 @@ soft_purge(Mod) -> Result end. - -do_old_soft_purge(Mod) -> - case erts_internal:copy_literals(Mod, true) of +do_soft_purge(Mod) -> + case erts_internal:purge_module(Mod, prepare) of false -> true; true -> - DoPurge = check_proc_code(erlang:processes(), Mod, false), - true = erts_internal:copy_literals(Mod, false), - case DoPurge of - false -> - false; - true -> - erts_internal:purge_module(Mod), - true - end - end. - -do_soft_purge(Mod) -> - case check_proc_code(erlang:processes(), Mod, false) of - false -> false; - true -> erts_internal:purge_module(Mod) + Res = check_proc_code(erlang:processes(), Mod, false), + erts_internal:purge_module(Mod, + case Res of + false -> abort; + true -> complete + end) end. %% @@ -336,3 +323,72 @@ cpc_init(CpcS, [Pid|Pids], NoReqs) -> 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, Type, Ref) when Type == true; Type == false -> + Mon = erlang:monitor(process, From), + Res = case Type of + true -> do_test_hard_purge(Mod, From, Ref, Mon); + false -> do_test_soft_purge(Mod, From, Ref, Mon) + end, + From ! {test_purge, Res, Ref}, + erlang:demonitor(Mon, [flush]), + ok; +do_test_purge(_, _, _, _) -> + ok. + +do_test_soft_purge(Mod, From, Ref, Mon) -> + PrepRes = erts_internal:purge_module(Mod, prepare), + TestRes = test_progress(started, From, Mon, Ref, ok), + case PrepRes of + false -> + _ = test_progress(continued, From, Mon, Ref, TestRes), + true; + true -> + Res = check_proc_code(erlang:processes(), Mod, false), + _ = test_progress(continued, From, Mon, Ref, TestRes), + erts_internal:purge_module(Mod, + case Res of + false -> abort; + true -> complete + end) + end. + +do_test_hard_purge(Mod, From, Ref, Mon) -> + PrepRes = erts_internal:purge_module(Mod, prepare), + TestRes = test_progress(started, From, Mon, Ref, ok), + case PrepRes of + false -> + _ = test_progress(continued, From, Mon, Ref, TestRes), + {false, false}; + true -> + DidKill = check_proc_code(erlang:processes(), Mod, true), + _ = test_progress(continued, From, Mon, Ref, TestRes), + true = erts_internal:purge_module(Mod, complete), + {true, DidKill} + end. + +test_progress(_State, _From, _Mon, _Ref, died) -> + %% Test process died; continue so we wont + %% leave the system in an inconsistent + %% state... + died; +test_progress(started, From, Mon, Ref, ok) -> + From ! {started, Ref}, + receive + {'DOWN', Mon, process, From, _} -> died; + {continue, Ref} -> ok + end; +test_progress(continued, From, Mon, Ref, ok) -> + From ! {continued, Ref}, + receive + {'DOWN', Mon, process, From, _} -> died; + {complete, Ref} -> ok + end. + |