File 0290-erts-Rewrite-hash_SUITE-4gb_bin-tc-to-use-... of Package erlang

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File 0290-erts-Rewrite-hash_SUITE-4gb_bin-tc-to-use-less-memor.patch of Package erlang (Revision 6bc8bdb9448218a96809a06da74b3d6e)

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From 04b8354276085bd181c69a3167b61f91a9d54b97 Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Fri, 30 Apr 2021 11:48:00 +0200
Subject: [PATCH 2/2] erts: Rewrite hash_SUITE:4gb_bin tc to use less memory

The testcase has been rewritten to try its very best to
not keep the refc binaries used alive any longer than
strictly necessary.

Also, the GC calls now wait for the mseg cache to be flushed
before returning so that we know that the memory has been
returned to the OS.
---
 erts/emulator/test/hash_SUITE.erl | 115 ++++++++++++++++++++++--------
 1 file changed, 87 insertions(+), 28 deletions(-)

diff --git a/erts/emulator/test/hash_SUITE.erl b/erts/emulator/test/hash_SUITE.erl
index 86b4460b38..e8b284b2d0 100644
--- a/erts/emulator/test/hash_SUITE.erl
+++ b/erts/emulator/test/hash_SUITE.erl
@@ -557,38 +557,41 @@ last_byte(Bin) ->
     <<_:NotLastByteSize/bitstring, LastByte:8>> = Bin,
     LastByte.
 
+
+%% This testcase needs 8-10 GB of free memory. If not enough is available
+%% the testcase will fail with {erpc,noconnection}
 test_phash2_4GB_plus_bin(Config) when is_list(Config) ->
     run_when_enough_resources(
       fun() ->
               {ok, N} = start_node(?FUNCTION_NAME),
               erpc:call(N,
                         fun() ->
-                                erts_debug:set_internal_state(available_internal_state, true),
-                                %% Created Bin4GB here so it only needs to be created once
-                                erts_debug:set_internal_state(force_gc, self()),
-                                Bin4GB = get_4GB_bin(),
-                                test_phash2_plus_bin_helper1(Bin4GB, <<>>, <<>>, 13708901),
-                                erts_debug:set_internal_state(force_gc, self()),
-                                test_phash2_plus_bin_helper1(Bin4GB, <<>>, <<3:5>>, 66617678),
-                                erts_debug:set_internal_state(force_gc, self()),
-                                test_phash2_plus_bin_helper1(Bin4GB, <<13>>, <<>>, 31308392),
-                                erts_debug:set_internal_state(force_gc, self()),
-                                erts_debug:set_internal_state(available_internal_state, false)
+                                test_phash2_4GB_plus_bin_tc()
                         end),
               stop_node(N)
       end).
 
+test_phash2_4GB_plus_bin_tc() ->
+    erts_debug:set_internal_state(available_internal_state, true),
+    test_phash2_gc(),
+    test_phash2_plus_bin_helper(fun get_4GB_bin/0, <<>>, <<>>, 13708901),
+    test_phash2_gc(),
+    test_phash2_plus_bin_helper(fun get_4GB_bin/0, <<>>, <<3:5>>, 66617678),
+    test_phash2_gc(),
+    test_phash2_plus_bin_helper(fun get_4GB_bin/0, <<13>>, <<>>, 31308392),
+    test_phash2_gc(),
+    erts_debug:set_internal_state(available_internal_state, false),
+    ok.
 
 test_phash2_10MB_plus_bin(Config) when is_list(Config) ->
     erts_debug:set_internal_state(available_internal_state, true),
-    erts_debug:set_internal_state(force_gc, self()),
-    Bin10MB = get_10MB_bin(),
-    test_phash2_plus_bin_helper1(Bin10MB, <<>>, <<>>, 22776267),
-    erts_debug:set_internal_state(force_gc, self()),
-    test_phash2_plus_bin_helper1(Bin10MB, <<>>, <<3:5>>, 124488972),
-    erts_debug:set_internal_state(force_gc, self()),
-    test_phash2_plus_bin_helper1(Bin10MB, <<13>>, <<>>, 72958346),
-    erts_debug:set_internal_state(force_gc, self()),
+    test_phash2_gc(),
+    test_phash2_plus_bin_helper(fun get_10MB_bin/0, <<>>, <<>>, 22776267),
+    test_phash2_gc(),
+    test_phash2_plus_bin_helper(fun get_10MB_bin/0, <<>>, <<3:5>>, 124488972),
+    test_phash2_gc(),
+    test_phash2_plus_bin_helper(fun get_10MB_bin/0, <<13>>, <<>>, 72958346),
+    test_phash2_gc(),
     erts_debug:set_internal_state(available_internal_state, false).
 
 get_10MB_bin() ->
@@ -612,39 +615,86 @@ duplicate_iolist(IOList, 0) ->
 duplicate_iolist(IOList, NrOfTimes) ->
     duplicate_iolist([IOList, IOList], NrOfTimes - 1).
 
-test_phash2_plus_bin_helper1(Bin4GB, ExtraBytes, ExtraBits, ExpectedHash) ->
-    test_phash2_plus_bin_helper2(Bin4GB, fun id/1, ExtraBytes, ExtraBits, ExpectedHash),
-    test_phash2_plus_bin_helper2(Bin4GB, fun make_unaligned_sub_bitstring/1, ExtraBytes, ExtraBits, ExpectedHash).
 
-test_phash2_plus_bin_helper2(Bin, TransformerFun, ExtraBytes, ExtraBits, ExpectedHash) ->
+%% This functions is written very carefully so that the binaries
+%% created are released as quickly as possible. If they are not released
+%% then the memory consumption going through the roof and systems will need
+%% lots of memory.
+test_phash2_plus_bin_helper(Bin4GB, ExtraBytes, ExtraBits, ExpectedHash) ->
+    ct:log("Test with ~p extra bytes and ~p extra bits",
+          [ExtraBytes, ExtraBits]),
+    test_phash2_plus_bin_helper(Bin4GB, fun id/1, ExtraBytes, ExtraBits, ExpectedHash),
+    ct:log("Test as unaligned sub bitstring"),
+    test_phash2_plus_bin_helper(Bin4GB, fun make_unaligned_sub_bitstring/1,
+                                ExtraBytes, ExtraBits, ExpectedHash).
+test_phash2_plus_bin_helper(Bin, TransformerFun, ExtraBytes, ExtraBits, ExpectedHash) ->
+    %% GC to free any binaries used by previous test cases
+    test_phash2_gc(),
     ExtraBitstring = << ExtraBytes/binary, ExtraBits/bitstring >>,
     LargerBitstring = << ExtraBytes/binary,
                          ExtraBits/bitstring,
-                         Bin/bitstring >>,
+                         (Bin())/bitstring >>,
+    %% GC to free binary created by Bin()
+    test_phash2_gc(),
     LargerTransformedBitstring = TransformerFun(LargerBitstring),
+    %% GC to free binary LargerBitstring
+    test_phash2_gc(),
     ExtraBitstringHash = erlang:phash2(ExtraBitstring),
     ExpectedHash =
         case size(LargerTransformedBitstring) < 4294967296 of
             true ->
-                erts_debug:set_internal_state(force_gc, self()),
                 erts_debug:set_internal_state(reds_left, 1),
                 Hash = erlang:phash2(LargerTransformedBitstring),
                 Hash = erlang:phash2(LargerTransformedBitstring),
                 Hash;
             false ->
-                erts_debug:set_internal_state(force_gc, self()),
                 erts_debug:set_internal_state(reds_left, 1),
                 ExtraBitstringHash = erlang:phash2(LargerTransformedBitstring),
                 ExtraBitstringHash = erlang:phash2(LargerTransformedBitstring),
                 ExtraBitstringHash
         end.
 
+test_phash2_gc() ->
+    erts_debug:set_internal_state(force_gc, self()),
+    wait_for_mseg_cache(10).
+
+%% We want to wait for the mseg cache to clear as otherwise the
+%% extra refc binaries may still use memory and cause the system
+%% to run out when it should not.
+wait_for_mseg_cache(0) ->
+    io:format("Cached segments never became zero, continue anyways.");
+wait_for_mseg_cache(N) ->
+    case get_cached_segments() of
+        0 ->
+            %% We sleep an extra second in order for the OS to catch up
+            timer:sleep(1000);
+        NotZero ->
+            io:format("Cached segments = ~p, sleeping for 1 second~n",
+                      [NotZero]),
+            timer:sleep(1000),
+            wait_for_mseg_cache(N-1)
+    end.
+
+get_cached_segments() ->
+    case erlang:system_info({allocator,mseg_alloc}) of
+        false ->
+            0;
+        MsegInfo ->
+            lists:foldl(
+              fun({instance,_,Info}, Acc) ->
+                      Kind = proplists:get_value(memkind, Info),
+                      Status = proplists:get_value(status, Kind),
+                      {cached_segments,Cached} = lists:keyfind(cached_segments, 1, Status),
+                      Acc + Cached
+              end, 0, MsegInfo)
+    end.
+
 run_when_enough_resources(Fun) ->
     Bits = 8 * erlang:system_info({wordsize,external}),
     Mem = total_memory(),
     Build = erlang:system_info(build_type),
 
-    if Bits =:= 64, is_integer(Mem), Mem >= 31,
+    if Bits =:= 64, is_integer(Mem), Mem >= 16,
        Build =/= valgrind, Build =/= asan ->
             Fun();
 
@@ -1257,9 +1307,18 @@ make_unaligned_sub_binary(Bin0) when is_binary(Bin0) ->
     <<0:3,Bin:Sz/binary,31:5>> = id(Bin1),
     Bin.
 
+%% This functions is written very carefully so that the bitstrings
+%% created are released as quickly as possible. If they are not released
+%% then the memory consumption going through the roof and systems will need
+%% lots of memory.
 make_unaligned_sub_bitstring(Bin0) ->
-    Bin1 = <<0:3,Bin0/bitstring,31:5>>,
     Sz = erlang:bit_size(Bin0),
+    Bin1 = <<0:3,Bin0/bitstring,31:5>>,
+    make_unaligned_sub_bitstring2(Sz, Bin1).
+
+make_unaligned_sub_bitstring2(Sz, Bin1) ->
+    %% Make sure to release Bin0 if possible
+    erlang:garbage_collect(),
     <<0:3,Bin:Sz/bitstring,31:5>> = id(Bin1),
     Bin.
 
-- 
2.31.1

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File 0290-erts-Rewrite-hash_SUITE-4gb_bin-tc-to-use-less-memor.patch of Package erlang (Revision 6bc8bdb9448218a96809a06da74b3d6e)

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