bpo-40514: Add --with-experimental-isolated-subinterpreters (GH-19926)
Add --with-experimental-isolated-subinterpreters build option to
configure: better isolate subinterpreters, experimental build mode.
When used, force the usage of the libc malloc() memory allocator,
since pymalloc relies on the unique global interpreter lock (GIL).
diff --git a/Misc/NEWS.d/next/Build/2020-05-05-15-39-11.bpo-40514.bZZmuS.rst b/Misc/NEWS.d/next/Build/2020-05-05-15-39-11.bpo-40514.bZZmuS.rst
new file mode 100644
index 0000000..ab9062c
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2020-05-05-15-39-11.bpo-40514.bZZmuS.rst
@@ -0,0 +1,2 @@
+Add ``--with-experimental-isolated-subinterpreters`` build option to
+``configure``: better isolate subinterpreters, experimental build mode.
diff --git a/Python/preconfig.c b/Python/preconfig.c
index 262738f..fd94d7d 100644
--- a/Python/preconfig.c
+++ b/Python/preconfig.c
@@ -291,7 +291,17 @@
config->coerce_c_locale_warn = 0;
config->dev_mode = -1;
+#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
+ /* bpo-40512: pymalloc is not compatible with subinterpreters,
+ force usage of libc malloc() which is thread-safe. */
+#ifdef Py_DEBUG
+ config->allocator = PYMEM_ALLOCATOR_MALLOC_DEBUG;
+#else
+ config->allocator = PYMEM_ALLOCATOR_MALLOC;
+#endif
+#else
config->allocator = PYMEM_ALLOCATOR_NOT_SET;
+#endif
#ifdef MS_WINDOWS
config->legacy_windows_fs_encoding = -1;
#endif
diff --git a/configure b/configure
index a8a35d0..26e9aa9 100755
--- a/configure
+++ b/configure
@@ -845,6 +845,7 @@
with_ensurepip
with_openssl
with_ssl_default_suites
+with_experimental_isolated_subinterpreters
'
ac_precious_vars='build_alias
host_alias
@@ -1575,6 +1576,9 @@
leave OpenSSL's defaults untouched, STRING: use a
custom string, PROTOCOL_SSLv2 ignores the setting,
see Doc/library/ssl.rst
+ --with-experimental-isolated-subinterpreters
+ better isolate subinterpreters, experimental build
+ mode (default is no)
Some influential environment variables:
MACHDEP name for machine-dependent library files
@@ -17489,6 +17493,30 @@
fi
+# --with-experimental-isolated-subinterpreters
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-experimental-isolated-subinterpreters" >&5
+$as_echo_n "checking for --with-experimental-isolated-subinterpreters... " >&6; }
+
+# Check whether --with-experimental-isolated-subinterpreters was given.
+if test "${with_experimental_isolated_subinterpreters+set}" = set; then :
+ withval=$with_experimental_isolated_subinterpreters;
+if test "$withval" != no
+then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; };
+ $as_echo "#define EXPERIMENTAL_ISOLATED_SUBINTERPRETERS 1" >>confdefs.h
+
+else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; };
+fi
+else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
# generate output files
ac_config_files="$ac_config_files Makefile.pre Misc/python.pc Misc/python-embed.pc Misc/python-config.sh"
diff --git a/configure.ac b/configure.ac
index f996051..acb6d4b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5717,6 +5717,23 @@
AC_DEFINE(PY_SSL_DEFAULT_CIPHERS, 1)
])
+# --with-experimental-isolated-subinterpreters
+AH_TEMPLATE(EXPERIMENTAL_ISOLATED_SUBINTERPRETERS,
+ [Better isolate subinterpreters, experimental build mode.])
+AC_MSG_CHECKING(for --with-experimental-isolated-subinterpreters)
+AC_ARG_WITH(experimental-isolated-subinterpreters,
+ AS_HELP_STRING([--with-experimental-isolated-subinterpreters],
+ [better isolate subinterpreters, experimental build mode (default is no)]),
+[
+if test "$withval" != no
+then
+ AC_MSG_RESULT(yes);
+ AC_DEFINE(EXPERIMENTAL_ISOLATED_SUBINTERPRETERS)
+else
+ AC_MSG_RESULT(no);
+fi],
+[AC_MSG_RESULT(no)])
+
# generate output files
AC_CONFIG_FILES(Makefile.pre Misc/python.pc Misc/python-embed.pc Misc/python-config.sh)
diff --git a/pyconfig.h.in b/pyconfig.h.in
index 75ac368..c06c495 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -38,6 +38,9 @@
/* Define if --enable-ipv6 is specified */
#undef ENABLE_IPV6
+/* Better isolate subinterpreters, experimental build mode. */
+#undef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
+
/* Define to 1 if your system stores words within floats with the most
significant word first */
#undef FLOAT_WORDS_BIGENDIAN