Merge pull request #2014 from pguyot/w49/fix-jit-mmap-size-estimation

Fix mmap size estimation for Elixir.ErlangError on aarch64

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

Author: bettio

libs/estdlib/src/code_server.erl

@@ -201,13 +201,14 @@ load(Module) ->
     end.
 
 %% @doc Estimate the required native code for a given bytecode size.
-%% Currently, the only live stream backend is mmap which needs this estimate
-%% and should not be passed a value too large to not slow down valgrind too
-%% much during tests. A factor of 20 is more than enough, the ratio is closer
-%% to 9 on x86-64.
-%% This will need some rework once we start using flash on MCUs.
+%% Currently, the only live stream backend that needs estimate is mmap
+%% and it should not be passed a value too large to not slow down valgrind too
+%% much during tests. A factor of 32 is more than enough, the largest observed
+%% ration is 21 for aarch64 and Elixir code. Also apply a minimum of 128 kb
+%% which shouldn't affect valgrind too much.
+%% jit_stream_flash and jit_stream_binary ignore the size parameter.
 %% @return size in bytes
 %% @param Size bytecode size
 -spec jit_mmap_size(pos_integer()) -> pos_integer().
 jit_mmap_size(Size) ->
-    Size * 20.
+    max(Size * 32, 128 * 1024).