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-rw-r--r--lib/mnesia/src/mnesia_locker.erl114
1 files changed, 75 insertions, 39 deletions
diff --git a/lib/mnesia/src/mnesia_locker.erl b/lib/mnesia/src/mnesia_locker.erl
index 6e21332480..55df074c29 100644
--- a/lib/mnesia/src/mnesia_locker.erl
+++ b/lib/mnesia/src/mnesia_locker.erl
@@ -66,8 +66,8 @@
-record(queue, {oid, tid, op, pid, lucky}).
-%% mnesia_held_locks: contain {{Oid,Tid}, Op} entries
--define(match_oid_held_locks(Oid), {{Oid, '_'}, '_'}).
+%% mnesia_held_locks: contain {Oid, MaxLock, [{Op, Tid}]} entries
+-define(match_oid_held_locks(Oid), {Oid, '_', '_'}).
%% mnesia_tid_locks: contain {Tid, Oid, Op} entries (bag)
-define(match_oid_tid_locks(Tid), {Tid, '_', '_'}).
%% mnesia_sticky_locks: contain {Oid, Node} entries and {Tab, Node} entries (set)
@@ -237,7 +237,14 @@ loop(State) ->
set_lock(Tid, Oid, Op) ->
?dbg("Granted ~p ~p ~p~n", [Tid,Oid,Op]),
- ?ets_insert(mnesia_held_locks, {{Oid, Tid}, Op}),
+ case ?ets_lookup(mnesia_held_locks, Oid) of
+ [] ->
+ ?ets_insert(mnesia_held_locks, {Oid, Op, [{Op, Tid}]});
+ [{Oid, Prev, Items}] when Op == read ->
+ ?ets_insert(mnesia_held_locks, {Oid, Prev, [{Op, Tid}|Items]});
+ [{Oid, _, Items}] when Op == write ->
+ ?ets_insert(mnesia_held_locks, {Oid, Op, [{Op, Tid}|Items]})
+ end,
?ets_insert(mnesia_tid_locks, {Tid, Oid, Op}).
%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -321,19 +328,19 @@ grant_lock(Tid, write, Lock, Oid) ->
can_lock(Tid, read, {Tab, Key}, AlreadyQ) when Key /= ?ALL ->
%% The key is bound, no need for the other BIF
Oid = {Tab, Key},
- ObjLocks = ?ets_match_object(mnesia_held_locks, {{Oid, '_'}, write}),
- TabLocks = ?ets_match_object(mnesia_held_locks, {{{Tab, ?ALL}, '_'}, write}),
+ ObjLocks = filter_write(?ets_lookup(mnesia_held_locks, Oid)),
+ TabLocks = filter_write(?ets_lookup(mnesia_held_locks, {Tab, ?ALL})),
check_lock(Tid, Oid, ObjLocks, TabLocks, yes, AlreadyQ, read);
can_lock(Tid, read, Oid, AlreadyQ) -> % Whole tab
Tab = element(1, Oid),
- ObjLocks = ?ets_match_object(mnesia_held_locks, {{{Tab, '_'}, '_'}, write}),
+ ObjLocks = ?ets_match_object(mnesia_held_locks, {{Tab, '_'}, write, '_'}),
check_lock(Tid, Oid, ObjLocks, [], yes, AlreadyQ, read);
can_lock(Tid, write, {Tab, Key}, AlreadyQ) when Key /= ?ALL ->
Oid = {Tab, Key},
- ObjLocks = ?ets_match_object(mnesia_held_locks, ?match_oid_held_locks(Oid)),
- TabLocks = ?ets_match_object(mnesia_held_locks, ?match_oid_held_locks({Tab, ?ALL})),
+ ObjLocks = ?ets_lookup(mnesia_held_locks, Oid),
+ TabLocks = ?ets_lookup(mnesia_held_locks, {Tab, ?ALL}),
check_lock(Tid, Oid, ObjLocks, TabLocks, yes, AlreadyQ, write);
can_lock(Tid, write, Oid, AlreadyQ) -> % Whole tab
@@ -341,29 +348,16 @@ can_lock(Tid, write, Oid, AlreadyQ) -> % Whole tab
ObjLocks = ?ets_match_object(mnesia_held_locks, ?match_oid_held_locks({Tab, '_'})),
check_lock(Tid, Oid, ObjLocks, [], yes, AlreadyQ, write).
+filter_write([{_, read, _}]) -> [];
+filter_write(Res) -> Res.
+
%% Check held locks for conflicting locks
-check_lock(Tid, Oid, [{{_,Tid}, _} | Locks], TabLocks, X, AlreadyQ, Type) ->
- check_lock(Tid, Oid, Locks, TabLocks, X, AlreadyQ, Type);
-check_lock(Tid, Oid, [Lock = {{_,WaitForTid}, _} | Locks], TabLocks, _X, AlreadyQ, Type) ->
- Queue = allowed_to_be_queued(WaitForTid,Tid),
- if Queue == true ->
- check_lock(Tid, Oid, Locks, TabLocks, {queue, WaitForTid}, AlreadyQ, Type);
- Tid#tid.pid == WaitForTid#tid.pid ->
- dbg_out("Spurious lock conflict ~w ~w: ~w -> ~w~n",
- [Oid, Lock, Tid, WaitForTid]),
- %% Test..
- {Tab, _Key} = Oid,
- HaveQ = (ets:lookup(mnesia_lock_queue, Oid) /= [])
- orelse (ets:lookup(mnesia_lock_queue,{Tab,?ALL}) /= []),
- if
- HaveQ ->
- {no, WaitForTid};
- true ->
- check_lock(Tid,Oid,Locks,TabLocks,{queue,WaitForTid},AlreadyQ,Type)
- end;
- %%{no, WaitForTid}; Safe solution
- true ->
- {no, WaitForTid}
+check_lock(Tid, Oid, [{_, _, Lock} | Locks], TabLocks, _X, AlreadyQ, Type) ->
+ case can_queue(Lock, Tid, Oid, _X) of
+ {no, _} = Res ->
+ Res;
+ Res ->
+ check_lock(Tid, Oid, Locks, TabLocks, Res, AlreadyQ, Type)
end;
check_lock(_, _, [], [], X, {queue, bad_luck}, _) ->
@@ -400,6 +394,26 @@ check_lock(Tid, Oid, [], [], X, AlreadyQ, Type) ->
check_lock(Tid, Oid, [], TabLocks, X, AlreadyQ, Type) ->
check_lock(Tid, Oid, TabLocks, [], X, AlreadyQ, Type).
+can_queue([{_Op, Tid}|Locks], Tid, Oid, Res) ->
+ can_queue(Locks, Tid, Oid, Res);
+can_queue([{Op, WaitForTid}|Locks], Tid, Oid = {Tab, _}, _) ->
+ case allowed_to_be_queued(WaitForTid,Tid) of
+ true when Tid#tid.pid == WaitForTid#tid.pid ->
+ dbg_out("Spurious lock conflict ~w ~w: ~w -> ~w~n",
+ [Oid, Op, Tid, WaitForTid]),
+ HaveQ = (ets:lookup(mnesia_lock_queue, Oid) /= [])
+ orelse (ets:lookup(mnesia_lock_queue,{Tab,?ALL}) /= []),
+ case HaveQ of
+ true -> {no, WaitForTid};
+ false -> can_queue(Locks, Tid, Oid, {queue, WaitForTid})
+ end;
+ true ->
+ can_queue(Locks, Tid, Oid, {queue, WaitForTid});
+ false ->
+ {no, WaitForTid}
+ end;
+can_queue([], _, _, Res) -> Res.
+
%% True if WaitForTid > Tid -> % Important order
allowed_to_be_queued(WaitForTid, Tid) ->
case get(pid_sort_order) of
@@ -517,12 +531,23 @@ release_locks([]) ->
release_lock({Tid, Oid, {queued, _}}) ->
?ets_match_delete(mnesia_lock_queue, #queue{oid=Oid, tid = Tid, op = '_',
pid = '_', lucky = '_'});
-release_lock({Tid, Oid, Op}) ->
- if
- Op == write ->
- ?ets_delete(mnesia_held_locks, {Oid, Tid});
- Op == read ->
- ets:delete_object(mnesia_held_locks, {{Oid, Tid}, Op})
+release_lock({This, Oid, Op}) ->
+ case ?ets_lookup(mnesia_held_locks, Oid) of
+ [] -> ok;
+ [{Oid, Prev, Locks0}] ->
+ Locks = [{TOp, Tid} || {TOp, Tid} <- Locks0, Tid =/= This],
+ if Locks =:= [] ->
+ ?ets_delete(mnesia_held_locks, Oid);
+ Op =:= read ->
+ ?ets_insert(mnesia_held_locks, {Oid, Prev, Locks});
+ true ->
+ case lists:any(fun({TOp, _}) -> TOp =:= write end, Locks) of
+ true ->
+ ?ets_insert(mnesia_held_locks, {Oid, write, Locks});
+ false ->
+ ?ets_insert(mnesia_held_locks, {Oid, read, Locks})
+ end
+ end
end.
rearrange_queue([{_Tid, {Tab, Key}, _} | Locks]) ->
@@ -1113,12 +1138,23 @@ rec_requests([], _Oid, _Store) ->
get_held_locks() ->
?MODULE ! {get_table, self(), mnesia_held_locks},
- Locks = receive {mnesia_held_locks, Ls} -> Ls end,
- [{Oid, Op, Tid} || {{Oid, Tid}, Op} <- Locks].
+ Locks = receive {mnesia_held_locks, Ls} -> Ls after 5000 -> [] end,
+ rewrite_locks(Locks, []).
+
+rewrite_locks([{Oid, _, Ls}|Locks], Acc0) ->
+ Acc = rewrite_locks(Ls, Oid, Acc0),
+ rewrite_locks(Locks, Acc);
+rewrite_locks([], Acc) ->
+ lists:reverse(Acc).
+
+rewrite_locks([{Op, Tid}|Ls], Oid, Acc) ->
+ rewrite_locks(Ls, Oid, [{Oid, Op, Tid}|Acc]);
+rewrite_locks([], _, Acc) ->
+ Acc.
get_lock_queue() ->
?MODULE ! {get_table, self(), mnesia_lock_queue},
- Q = receive {mnesia_lock_queue, Locks} -> Locks end,
+ Q = receive {mnesia_lock_queue, Locks} -> Locks after 5000 -> [] end,
[{Oid, Op, Pid, Tid, WFT} || {queue, Oid, Tid, Op, Pid, WFT} <- Q].
do_stop() ->
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 18:53:46 +0000