gh-81057: Move Threading-Related Globals to _PyRuntimeState (#100084)

https://github.com/python/cpython/issues/81057

Include/internal/pycore_pythread.h

@@ -0,0 +1,81 @@
+#ifndef Py_INTERNAL_PYTHREAD_H
+#define Py_INTERNAL_PYTHREAD_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
+
+#ifndef _POSIX_THREADS
+/* This means pthreads are not implemented in libc headers, hence the macro
+   not present in unistd.h. But they still can be implemented as an external
+   library (e.g. gnu pth in pthread emulation) */
+# ifdef HAVE_PTHREAD_H
+#  include <pthread.h> /* _POSIX_THREADS */
+# endif
+# ifndef _POSIX_THREADS
+/* Check if we're running on HP-UX and _SC_THREADS is defined. If so, then
+   enough of the Posix threads package is implemented to support python
+   threads.
+
+   This is valid for HP-UX 11.23 running on an ia64 system. If needed, add
+   a check of __ia64 to verify that we're running on an ia64 system instead
+   of a pa-risc system.
+*/
+#  ifdef __hpux
+#   ifdef _SC_THREADS
+#    define _POSIX_THREADS
+#   endif
+#  endif
+# endif /* _POSIX_THREADS */
+#endif /* _POSIX_THREADS */
+
+#if defined(_POSIX_THREADS) && !defined(HAVE_PTHREAD_STUBS)
+# define _USE_PTHREADS
+#endif
+
+#if defined(_USE_PTHREADS) && defined(HAVE_PTHREAD_CONDATTR_SETCLOCK) && defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
+// monotonic is supported statically.  It doesn't mean it works on runtime.
+# define CONDATTR_MONOTONIC
+#endif
+
+
+#if defined(HAVE_PTHREAD_STUBS)
+// pthread_key
+struct py_stub_tls_entry {
+    bool in_use;
+    void *value;
+};
+#endif
+
+struct _pythread_runtime_state {
+    int initialized;
+
+#ifdef _USE_PTHREADS
+    // This matches when thread_pthread.h is used.
+    struct {
+        /* NULL when pthread_condattr_setclock(CLOCK_MONOTONIC) is not supported. */
+        pthread_condattr_t *ptr;
+# ifdef CONDATTR_MONOTONIC
+    /* The value to which condattr_monotonic is set. */
+        pthread_condattr_t val;
+# endif
+    } _condattr_monotonic;
+
+#endif  // USE_PTHREADS
+
+#if defined(HAVE_PTHREAD_STUBS)
+    struct {
+        struct py_stub_tls_entry tls_entries[PTHREAD_KEYS_MAX];
+    } stubs;
+#endif
+};
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_INTERNAL_PYTHREAD_H */

Include/internal/pycore_runtime.h

@@ -20,6 +20,7 @@ extern "C" {
 #include "pycore_parser.h"          // struct _parser_runtime_state
 #include "pycore_pymem.h"           // struct _pymem_allocators
 #include "pycore_pyhash.h"          // struct pyhash_runtime_state
+#include "pycore_pythread.h"        // struct _pythread_runtime_state
 #include "pycore_obmalloc.h"        // struct obmalloc_state
 #include "pycore_time.h"            // struct _time_runtime_state
 #include "pycore_unicodeobject.h"   // struct _Py_unicode_runtime_ids
@@ -96,6 +97,7 @@ typedef struct pyruntimestate {
         int unhandled_keyboard_interrupt;
     } signals;
     struct _time_runtime_state time;
+    struct _pythread_runtime_state threads;
 
     struct pyinterpreters {
         PyThread_type_lock mutex;

Makefile.pre.in

@@ -1663,6 +1663,7 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/internal/pycore_pymem.h \
 		$(srcdir)/Include/internal/pycore_pymem_init.h \
 		$(srcdir)/Include/internal/pycore_pystate.h \
+		$(srcdir)/Include/internal/pycore_pythread.h \
 		$(srcdir)/Include/internal/pycore_range.h \
 		$(srcdir)/Include/internal/pycore_runtime.h \
 		$(srcdir)/Include/internal/pycore_runtime_init_generated.h \

PCbuild/pythoncore.vcxproj

@@ -245,6 +245,7 @@
     <ClInclude Include="..\Include\internal\pycore_pymem.h" />
     <ClInclude Include="..\Include\internal\pycore_pymem_init.h" />
     <ClInclude Include="..\Include\internal\pycore_pystate.h" />
+    <ClInclude Include="..\Include\internal\pycore_pythread.h" />
     <ClInclude Include="..\Include\internal\pycore_range.h" />
     <ClInclude Include="..\Include\internal\pycore_runtime.h" />
     <ClInclude Include="..\Include\internal\pycore_runtime_init.h" />

PCbuild/pythoncore.vcxproj.filters

@@ -639,6 +639,9 @@
     <ClInclude Include="..\Include\internal\pycore_pystate.h">
       <Filter>Include\internal</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_pythread.h">
+      <Filter>Include\internal</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\internal\pycore_range.h">
       <Filter>Include\internal</Filter>
     </ClInclude>

Python/thread.c

@@ -8,15 +8,7 @@
 #include "Python.h"
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
 #include "pycore_structseq.h"     // _PyStructSequence_FiniType()
-
-#ifndef _POSIX_THREADS
-/* This means pthreads are not implemented in libc headers, hence the macro
-   not present in unistd.h. But they still can be implemented as an external
-   library (e.g. gnu pth in pthread emulation) */
-# ifdef HAVE_PTHREAD_H
-#  include <pthread.h> /* _POSIX_THREADS */
-# endif
-#endif
+#include "pycore_pythread.h"
 
 #ifndef DONT_HAVE_STDIO_H
 #include <stdio.h>
@@ -24,33 +16,17 @@
 
 #include <stdlib.h>
 
-#ifndef _POSIX_THREADS
-
-/* Check if we're running on HP-UX and _SC_THREADS is defined. If so, then
-   enough of the Posix threads package is implemented to support python
-   threads.
-
-   This is valid for HP-UX 11.23 running on an ia64 system. If needed, add
-   a check of __ia64 to verify that we're running on an ia64 system instead
-   of a pa-risc system.
-*/
-#ifdef __hpux
-#ifdef _SC_THREADS
-#define _POSIX_THREADS
-#endif
-#endif
-
-#endif /* _POSIX_THREADS */
-
-static int initialized;
 
 static void PyThread__init_thread(void); /* Forward */
 
+#define initialized _PyRuntime.threads.initialized
+
 void
 PyThread_init_thread(void)
 {
-    if (initialized)
+    if (initialized) {
         return;
+    }
     initialized = 1;
     PyThread__init_thread();
 }
@@ -58,7 +34,7 @@ PyThread_init_thread(void)
 #if defined(HAVE_PTHREAD_STUBS)
 #   define PYTHREAD_NAME "pthread-stubs"
 #   include "thread_pthread_stubs.h"
-#elif defined(_POSIX_THREADS)
+#elif defined(_USE_PTHREADS)  /* AKA _PTHREADS */
 #   if defined(__EMSCRIPTEN__) && !defined(__EMSCRIPTEN_PTHREADS__)
 #     define PYTHREAD_NAME "pthread-stubs"
 #   else

Python/thread_nt.h

@@ -152,11 +152,12 @@ unsigned long PyThread_get_thread_native_id(void);
 #endif
 
 /*
- * Initialization of the C package, should not be needed.
+ * Initialization for the current runtime.
  */
 static void
 PyThread__init_thread(void)
 {
+    // Initialization of the C package should not be needed.
 }
 
 /*

Python/thread_pthread.h

@@ -119,20 +119,16 @@
  * pthread_cond support
  */
 
-#if defined(HAVE_PTHREAD_CONDATTR_SETCLOCK) && defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
-// monotonic is supported statically.  It doesn't mean it works on runtime.
-#define CONDATTR_MONOTONIC
-#endif
-
-// NULL when pthread_condattr_setclock(CLOCK_MONOTONIC) is not supported.
-static pthread_condattr_t *condattr_monotonic = NULL;
+#define condattr_monotonic _PyRuntime.threads._condattr_monotonic.ptr
 
 static void
 init_condattr(void)
 {
 #ifdef CONDATTR_MONOTONIC
-    static pthread_condattr_t ca;
+# define ca _PyRuntime.threads._condattr_monotonic.val
+    // XXX We need to check the return code?
     pthread_condattr_init(&ca);
+    // XXX We need to run pthread_condattr_destroy() during runtime fini.
     if (pthread_condattr_setclock(&ca, CLOCK_MONOTONIC) == 0) {
         condattr_monotonic = &ca;  // Use monotonic clock
     }
@@ -192,15 +188,21 @@ typedef struct {
     "%s: %s\n", name, strerror(status)); error = 1; }
 
 /*
- * Initialization.
+ * Initialization for the current runtime.
  */
 static void
 PyThread__init_thread(void)
 {
+    // The library is only initialized once in the process,
+    // regardless of how many times the Python runtime is initialized.
+    static int lib_initialized = 0;
+    if (!lib_initialized) {
+        lib_initialized = 1;
 #if defined(_AIX) && defined(__GNUC__)
-    extern void pthread_init(void);
-    pthread_init();
+        extern void pthread_init(void);
+        pthread_init();
 #endif
+    }
     init_condattr();
 }
 

Python/thread_pthread_stubs.h

@@ -124,13 +124,10 @@ pthread_attr_destroy(pthread_attr_t *attr)
     return 0;
 }
 
-// pthread_key
-typedef struct {
-    bool in_use;
-    void *value;
-} py_tls_entry;
 
-static py_tls_entry py_tls_entries[PTHREAD_KEYS_MAX] = {0};
+typedef struct py_stub_tls_entry py_tls_entry;
+
+#define py_tls_entries (_PyRuntime.threads.stubs.tls_entries)
 
 int
 pthread_key_create(pthread_key_t *key, void (*destr_function)(void *))

Tools/c-analyzer/cpython/globals-to-fix.tsv

@@ -306,7 +306,6 @@ Objects/sliceobject.c	-	_Py_EllipsisObject	-
 ## state
 
 Objects/object.c	-	_Py_RefTotal	-
-Python/thread_pthread_stubs.h	-	py_tls_entries	-
 
 
 ##################################

Tools/c-analyzer/cpython/ignored.tsv

@@ -22,11 +22,8 @@ Python/fileutils.c	set_inheritable	ioctl_works	-
 # XXX Is this thread-safe?
 Modules/posixmodule.c	os_dup2_impl	dup3_works	-
 
-## resource init - set during first init
-Python/thread.c	-	initialized	-
-Python/thread_pthread.h	-	condattr_monotonic	-
-# safe static buffer used during one-time initialization
-Python/thread_pthread.h	init_condattr	ca	-
+## guards around resource init
+Python/thread_pthread.h	PyThread__init_thread	lib_initialized	-
 
 ##-----------------------
 ## other values (not Python-specific)