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authorRichard Carlsson <[email protected]>2013-09-27 11:07:32 +0200
committerFredrik Gustafsson <[email protected]>2013-11-05 10:55:59 +0100
commitd64c016b8453ac143a6c26493a0fb1908f34ed99 (patch)
tree53dc0a2ebd203ebee2fc3e39f70ce0332eed9fbe
parent00a3dade2d58836bca334be36843775343e5e269 (diff)
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Avoid serialization on code_server in xmerl:export()
The inheritance mechanism in xmerl used to use 'catch apply(M,F,Args)' to try different modules M until one was found that had a function F/A. However, when M:F/A does not exist, apply/3 will trap to error_handler:undefined_function/3, which will call code:ensure_loaded(M), making a synchronous request to the code server process. If many processes tried to use xmerl:export() concurrently, they would get serialized waiting for the code server process. This patch uses erlang:function_exported/3 instead to check if M:F/A exists. If M exists, it should already have been loaded at that point due to the inheritance checking in the xmerl:callbacks/1 function.
-rw-r--r--lib/xmerl/src/xmerl.erl25
1 files changed, 12 insertions, 13 deletions
diff --git a/lib/xmerl/src/xmerl.erl b/lib/xmerl/src/xmerl.erl
index 3249094e78..01af183eef 100644
--- a/lib/xmerl/src/xmerl.erl
+++ b/lib/xmerl/src/xmerl.erl
@@ -303,18 +303,17 @@ apply_tag_cb(Ms, F, Args) ->
apply_cb(Ms, F, '#element#', Args).
apply_cb(Ms, F, Df, Args) ->
- apply_cb(Ms, F, Df, Args, Ms).
-
-apply_cb([M|Ms], F, Df, Args, Ms0) ->
- case catch apply(M, F, Args) of
- {'EXIT', {undef,[{M,F,_,_}|_]}} ->
- apply_cb(Ms, F, Df, Args, Ms0);
- {'EXIT', Reason} ->
- exit(Reason);
- Res ->
- Res
+ apply_cb(Ms, F, Df, Args, length(Args)).
+
+apply_cb(Ms, F, Df, Args, A) ->
+ apply_cb(Ms, F, Df, Args, A, Ms).
+
+apply_cb([M|Ms], F, Df, Args, A, Ms0) ->
+ case erlang:function_exported(M, F, A) of
+ true -> apply(M, F, Args);
+ false -> apply_cb(Ms, F, Df, Args, A, Ms0)
end;
-apply_cb([], Df, Df, Args, _Ms0) ->
+apply_cb([], Df, Df, Args, A, _Ms0) ->
exit({unknown_tag, {Df, Args}});
-apply_cb([], F, Df, Args, Ms0) ->
- apply_cb(Ms0, Df, Df, [F|Args]).
+apply_cb([], F, Df, Args, A, Ms0) ->
+ apply_cb(Ms0, Df, Df, [F|Args], A+1).