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authorRickard Green <rickard@erlang.org>2012-02-16 02:38:50 +0100
committerRickard Green <rickard@erlang.org>2012-02-19 22:57:50 +0100
commitcfb7f3fcffad43647be5b9b818310b44003b97ab (patch)
tree7be84d307c19b967fdc215d50126d14845c63743 /erts/lib_src/utils
parenta67091debf20c972dd7ce1a8379fee6673fbe571 (diff)
downloadotp-cfb7f3fcffad43647be5b9b818310b44003b97ab.tar.gz
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Misc memory barrier fixes
- Document barrier semantics - Introduce ddrb suffix on atomic ops - Barrier macros for both non-SMP and SMP case - Make the thread progress API a bit more intuitive
Diffstat (limited to 'erts/lib_src/utils')
-rwxr-xr-xerts/lib_src/utils/make_atomics_api285
1 files changed, 181 insertions, 104 deletions
diff --git a/erts/lib_src/utils/make_atomics_api b/erts/lib_src/utils/make_atomics_api
index f4e71c7618..d8b1a56100 100755
--- a/erts/lib_src/utils/make_atomics_api
+++ b/erts/lib_src/utils/make_atomics_api
@@ -4,7 +4,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2011. All Rights Reserved.
+%% Copyright Ericsson AB 2011-2012. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
@@ -50,7 +50,9 @@
-define(DW_RTCHK_MACRO, "ETHR_RTCHK_USE_NATIVE_DW_ATOMIC_IMPL__").
%% Barrier versions we implement
--define(BARRIERS, [none, rb, wb, acqb, relb, mb]).
+-define(BARRIERS, [none, ddrb, rb, wb, acqb, relb, mb]).
+-define(NON_NATIVE_BARRIERS, [ddrb]).
+-define(NATIVE_BARRIERS, (?BARRIERS -- ?NON_NATIVE_BARRIERS)).
-define(ATOMIC_SIZES, ["dword", "word", "32"]).
@@ -381,7 +383,6 @@ do_func_header(#atomic_context{dw = true,
cmpxchg, Inline, Func) ->
[Inline, "int ", Func, "(", AtomicT, " *", Arg1, ", ", AintT, " *", Arg2, ", ", AintT, " *", Arg3, ")"].
-
xbarriers(_Op, none, _NB) ->
{"", ""};
@@ -455,7 +456,7 @@ try_barrier_order_first(mb) ->
try_barrier_order(B) ->
First = try_barrier_order_first(B),
- First ++ (?BARRIERS -- First).
+ First ++ (?NATIVE_BARRIERS -- First).
native_barrier_op(#atomic_context{'NATMC' = NATMC} = AC, If, ExtraDecl, Op, B, NB, TypeCasts) ->
NOpStr = opstr(native(Op)),
@@ -571,12 +572,12 @@ do_cmpxchg_fallback_define(#atomic_context{'NATMC' = NATMC,
NoneTryBarrierOrder = try_barrier_order(none),
%% First a sanity check
["
-#if (", NotDefCMPXCHG(hd(?BARRIERS)) ,
+#if (", NotDefCMPXCHG(hd(?NATIVE_BARRIERS)) ,
lists:map(fun (B) ->
[" \\
&& ", NotDefCMPXCHG(B)]
end,
- tl(?BARRIERS)), ")
+ tl(?NATIVE_BARRIERS)), ")
# error \"No native cmpxchg() op available\"
#endif
@@ -744,7 +745,7 @@ translate_have_defs(#atomic_context{dw = DW, 'NATMC' = NATMC}) ->
]
end]
end,
- ?BARRIERS)
+ ?NATIVE_BARRIERS)
end,
case DW of
true -> ?DW_ATOMIC_OPS;
@@ -801,6 +802,46 @@ rtchk_fallback_call(Return, #atomic_context{dw = DW,
false -> [RetVar, " ="]
end, [?DW_FUNC_MACRO, "(", opstr(Op), op_barrier_ext(B), ")"], Arg1, Arg2, Arg3, "").
+non_native_barrier(B) ->
+ lists:member(B, ?NON_NATIVE_BARRIERS).
+
+non_native_barrier_impl(AC, Type, Macro, Op, B) ->
+ ["
+", func_header(AC, Type, Macro, Op, B), "
+{",
+ case B of
+ ddrb ->
+ ["
+#ifdef ETHR_ORDERED_READ_DEPEND
+ ", func_call(AC, Type, Macro, Op, none, true), "
+#else
+ ", func_call(AC, Type, Macro, Op, rb, true), "
+#endif
+"
+ ]
+ end,
+ "}
+"
+ ].
+
+func_call(#atomic_context{'ATMC' = ATMC} = AC, inline_implementation, _Macro, Op, B, RetStatement) ->
+ func_call(AC, Op, ["ETHR_", ATMC, "_FUNC__(", opstr(Op), op_barrier_ext(B), ")"], RetStatement);
+func_call(#atomic_context{atomic = Atomic} = AC, implementation, false, Op, B, RetStatement) ->
+ func_call(AC, Op, [Atomic, "_", opstr(Op), op_barrier_ext(B)], RetStatement);
+func_call(AC, implementation, Macro, Op, B, RetStatement) ->
+ func_call(AC, Op, [Macro, "(", opstr(Op), op_barrier_ext(B), ")"], RetStatement).
+
+func_call(#atomic_context{dw = DW, arg1 = Arg1, arg2 = Arg2, arg3 = Arg3} = AC, Op, Func, true) ->
+ op_call(Op, DW, case is_return_op(AC, Op) of
+ true -> "return";
+ false -> ""
+ end, Func, Arg1, Arg2, Arg3, "");
+func_call(#atomic_context{dw = DW, arg1 = Arg1, arg2 = Arg2, arg3 = Arg3, ret_var = RetVar} = AC, Op, Func, false) ->
+ op_call(Op, DW, case is_return_op(AC, Op) of
+ true -> [RetVar, " = "];
+ false -> ""
+ end, Func, Arg1, Arg2, Arg3, "").
+
make_implementations(#atomic_context{dw = DW,
ret_type = RetType,
ret_var = RetVar,
@@ -858,73 +899,78 @@ make_implementations(#atomic_context{dw = DW,
",
lists:map(fun (B) ->
- TryBarriers = try_barrier_order(B),
- ["
+ case non_native_barrier(B) of
+ true ->
+ non_native_barrier_impl(AC, inline_implementation, false, Op, B);
+ false ->
+ TryBarriers = try_barrier_order(B),
+ ["
", func_header(AC, inline_implementation, false, Op, B), "
{
",
- case is_return_op(AC, Op) of
- true ->
- [" ", RetType, " ", RetVar, ";\n"];
- _ -> ""
- end,
- case DW of
- true ->
- [RtchkBegin,
- "\n",
- su_dw_native_barrier_op(AC, "#if", Op, B, hd(TryBarriers)),
- lists:map(fun (NB) ->
- su_dw_native_barrier_op(AC, "#elif", Op, B, NB)
- end,
- tl(TryBarriers)),
- lists:map(fun (NB) ->
- dw_native_barrier_op(AC, "#elif", "", Op, B, NB)
- end,
- TryBarriers),
- case simple_fallback(AC, Op, B) of
- "" ->
- %% No simple fallback available;
- %% use cmpxchg() fallbacks...
- [cmpxchg_fallbacks(AC#atomic_context{'NATMC' = ["SU_", NATMC]}, true, Op, B),
- cmpxchg_fallbacks(AC, false, Op, B),
- "#else
+ case is_return_op(AC, Op) of
+ true ->
+ [" ", RetType, " ", RetVar, ";\n"];
+ _ -> ""
+ end,
+ case DW of
+ true ->
+ [RtchkBegin,
+ "\n",
+ su_dw_native_barrier_op(AC, "#if", Op, B, hd(TryBarriers)),
+ lists:map(fun (NB) ->
+ su_dw_native_barrier_op(AC, "#elif", Op, B, NB)
+ end,
+ tl(TryBarriers)),
+ lists:map(fun (NB) ->
+ dw_native_barrier_op(AC, "#elif", "", Op, B, NB)
+ end,
+ TryBarriers),
+ case simple_fallback(AC, Op, B) of
+ "" ->
+ %% No simple fallback available;
+ %% use cmpxchg() fallbacks...
+ [cmpxchg_fallbacks(AC#atomic_context{'NATMC' = ["SU_", NATMC]}, true, Op, B),
+ cmpxchg_fallbacks(AC, false, Op, B),
+ "#else
#error \"Missing implementation of ", Atomic, "_", opstr(Op), op_barrier_ext(B), "()!\"
#endif
"
- ];
- SimpleFallback ->
- ["#else\n", SimpleFallback, "#endif\n"]
- end,
- RtchkEnd(false, Op, B), "\n"];
- false ->
- [native_barrier_op(AC, "#if", "", Op, B, hd(TryBarriers), true),
- lists:map(fun (NB) ->
- native_barrier_op(AC, "#elif", "", Op, B, NB, true)
- end,
- tl(TryBarriers)),
- case simple_fallback(AC, Op, B) of
- "" ->
- %% No simple fallback available;
- %% use cmpxchg() fallbacks...
- [cmpxchg_fallbacks(AC, false, Op, B),
- "#else
+ ];
+ SimpleFallback ->
+ ["#else\n", SimpleFallback, "#endif\n"]
+ end,
+ RtchkEnd(false, Op, B), "\n"];
+ false ->
+ [native_barrier_op(AC, "#if", "", Op, B, hd(TryBarriers), true),
+ lists:map(fun (NB) ->
+ native_barrier_op(AC, "#elif", "", Op, B, NB, true)
+ end,
+ tl(TryBarriers)),
+ case simple_fallback(AC, Op, B) of
+ "" ->
+ %% No simple fallback available;
+ %% use cmpxchg() fallbacks...
+ [cmpxchg_fallbacks(AC, false, Op, B),
+ "#else
#error \"Missing implementation of ", Atomic, "_", opstr(Op), op_barrier_ext(B), "()!\"
#endif
"
- ];
- SimpleFallback ->
- ["#else\n", SimpleFallback, "#endif\n"]
- end]
- end,
- case is_return_op(AC, Op) of
- true ->
- [" return ", RetVar, ";\n"];
- false ->
- ""
- end,
- "}\n"]
+ ];
+ SimpleFallback ->
+ ["#else\n", SimpleFallback, "#endif\n"]
+ end]
+ end,
+ case is_return_op(AC, Op) of
+ true ->
+ [" return ", RetVar, ";\n"];
+ false ->
+ ""
+ end,
+ "}\n"]
+ end
end,
- ?BARRIERS)]
+ ?NATIVE_BARRIERS ++ ?NON_NATIVE_BARRIERS)] %% non-native needs to be after native...
end,
case DW of
true -> ?DW_ATOMIC_OPS;
@@ -1159,33 +1205,38 @@ int ethr_have_native_dw_atomic(void)
",
lists:map(fun (B) ->
- ["\n",
- func_header(AC, implementation,
- case DW of
- true -> ?DW_FUNC_MACRO;
- false -> false
- end, Op, B),
- "\n{\n",
- case is_return_op(AC, Op) of
- true -> [" ", RetType, " ", RetVar, ";\n"];
- false -> ""
- end,
- case Op of
- init -> "";
- _ -> [" ETHR_ASSERT(!ethr_not_inited__);\n"]
- end,
- [" ETHR_ASSERT(", Arg1, ");\n"],
- make_native_impl_op(AC, Op, B),
- make_amc_fallback_op(AC#atomic_context{arg1 = FallbackVar}, Op, B),
- make_locked_fallback_op(AC#atomic_context{arg1 = FallbackVar}, Op, B),
- case is_return_op(AC, Op) of
- true -> [" return ", RetVar, ";"
- ];
- false ->
- ""
- end,
- "\n}\n",
- make_symbol_to_fallback_impl(AC, Op, B)]
+ Macro = case DW of
+ true -> ?DW_FUNC_MACRO;
+ false -> false
+ end,
+ case non_native_barrier(B) of
+ true ->
+ non_native_barrier_impl(AC, implementation, Macro, Op, B);
+ false ->
+ ["\n",
+ func_header(AC, implementation, Macro, Op, B),
+ "\n{\n",
+ case is_return_op(AC, Op) of
+ true -> [" ", RetType, " ", RetVar, ";\n"];
+ false -> ""
+ end,
+ case Op of
+ init -> "";
+ _ -> [" ETHR_ASSERT(!ethr_not_inited__);\n"]
+ end,
+ [" ETHR_ASSERT(", Arg1, ");\n"],
+ make_native_impl_op(AC, Op, B),
+ make_amc_fallback_op(AC#atomic_context{arg1 = FallbackVar}, Op, B),
+ make_locked_fallback_op(AC#atomic_context{arg1 = FallbackVar}, Op, B),
+ case is_return_op(AC, Op) of
+ true -> [" return ", RetVar, ";"
+ ];
+ false ->
+ ""
+ end,
+ "\n}\n",
+ make_symbol_to_fallback_impl(AC, Op, B)]
+ end
end,
?BARRIERS)]
end,
@@ -1233,7 +1284,7 @@ static char *native_", DW, "atomic", Bits, "_ops[] = {",
#endif"
]
end,
- ?BARRIERS)
+ ?NATIVE_BARRIERS)
end,
case NBits of
"dw" -> ?DW_ATOMIC_OPS;
@@ -1390,25 +1441,51 @@ comments() ->
* Appart from a function implementing the atomic operation
* with unspecified memory barrier semantics, there are
* functions implementing each operation with the following
- * memory barrier semantics:
-",
+ * implied memory barrier semantics:",
lists:map(fun (none) ->
"";
- (rb) ->
- [" * - rb (read barrier)\n"];
- (wb) ->
- [" * - wb (write barrier)\n"];
+ (mb) ->
+ ["
+ * - mb - Full memory barrier. Orders both loads, and
+ * stores before, and after the atomic operation.
+ * No load or store is allowed to be reordered
+ * over the atomic operation."];
(acqb) ->
- [" * - acqb (acquire barrier)\n"];
+ ["
+ * - acqb - Acquire barrier. Orders both loads, and stores
+ * appearing *after* the atomic operation. These
+ * are not allowed to be reordered over the
+ * atomic operation."];
(relb) ->
- [" * - relb (release barrier)\n"];
- (mb) ->
- [" * - mb (full memory barrier)\n"];
+ ["
+ * - relb - Release barrier. Orders both loads, and
+ * stores appearing *before* the atomic
+ * operation. These are not allowed to be
+ * reordered over the atomic operation."];
+ (rb) ->
+ ["
+ * - rb - Read barrier. Orders *only* loads. These are
+ * not allowed to be reordered over the barrier.
+ * Load in atomic operation is ordered *before*
+ * the barrier. "];
+ (ddrb) ->
+ ["
+ * - ddrb - Data dependency read barrier. Orders *only*
+ * loads according to data dependency across the
+ * barrier. Load in atomic operation is ordered
+ * before the barrier."];
+ (wb) ->
+ ["
+ * - wb - Write barrier. Orders *only* stores. These are
+ * not allowed to be reordered over the barrier.
+ * Store in atomic operation is ordered *after*
+ * the barrier."];
(B) ->
[" * - ", a2l(B), "\n"]
end,
- ?BARRIERS),
- " *
+ lists:reverse(?BARRIERS)),
+ "
+ *
* We implement all of these operation/barrier
* combinations, regardless of whether they are useful
* or not (some of them are useless).