current/SOURCES/0003-fix-%23177_avoid-GIL-deadlock.patch

From 3e3893b0ee381098418d7b28997f6b861c53eff1 Mon Sep 17 00:00:00 2001
From: Alberto Gonzalez <mindhells@gmail.com>
Date: Wed, 28 Oct 2020 09:44:09 +0000
Subject: [PATCH] fix #177: avoid GIL deadlock

---
 fract4d/c/fract4dc/calcargs.cpp |  8 --------
 fract4d/c/fract4dc/calcs.cpp    | 31 ++++++++++++++++++++++++-------
 fract4d/c/fract4dmodule.cpp     |  1 +
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/fract4d/c/fract4dc/calcargs.cpp b/fract4d/c/fract4dc/calcargs.cpp
index 18eb83470..4296427da 100644
--- a/fract4d/c/fract4dc/calcargs.cpp
+++ b/fract4d/c/fract4dc/calcargs.cpp
@@ -1,5 +1,4 @@
 #include "Python.h"
-#include <mutex>
 
 #include "calcargs.h"
 
@@ -18,13 +17,10 @@ calc_args::calc_args()
     params = new double[N_PARAMS];
 }
 
-static std::mutex ref_count_mutex;
-
 void calc_args::set_cmap(PyObject *pycmap_)
 {
     pycmap = pycmap_;
     cmap = colormaps::cmap_fromcapsule(pycmap);
-    const std::lock_guard<std::mutex> lock(ref_count_mutex);
     Py_XINCREF(pycmap);
 }
 
@@ -32,7 +28,6 @@ void calc_args::set_pfo(PyObject *pypfo_)
 {
     pypfo = pypfo_;
     pfo = (loaders::pf_fromcapsule(pypfo))->pfo;
-    const std::lock_guard<std::mutex> lock(ref_count_mutex);
     Py_XINCREF(pypfo);
 }
 
@@ -40,14 +35,12 @@ void calc_args::set_im(PyObject *pyim_)
 {
     pyim = pyim_;
     im = images::image_fromcapsule(pyim);
-    const std::lock_guard<std::mutex> lock(ref_count_mutex);
     Py_XINCREF(pyim);
 }
 void calc_args::set_site(PyObject *pysite_)
 {
     pysite = pysite_;
     site = sites::site_fromcapsule(pysite);
-    const std::lock_guard<std::mutex> lock(ref_count_mutex);
     Py_XINCREF(pysite);
 }
 
@@ -57,7 +50,6 @@ calc_args::~calc_args()
 #ifdef DEBUG_CREATION
     fprintf(stderr, "%p : CA : DTOR\n", this);
 #endif
-    const std::lock_guard<std::mutex> lock(ref_count_mutex);
     Py_XDECREF(pycmap);
     Py_XDECREF(pypfo);
     Py_XDECREF(pyim);
diff --git a/fract4d/c/fract4dc/calcs.cpp b/fract4d/c/fract4dc/calcs.cpp
index 1509e8d99..4b9c9b0d3 100644
--- a/fract4d/c/fract4dc/calcs.cpp
+++ b/fract4d/c/fract4dc/calcs.cpp
@@ -46,11 +46,14 @@ namespace calcs {
 
         if (cargs->asynchronous)
         {
-            auto &site = *cargs->site;
-            site.interrupt();
-            site.wait();
-            site.start();
-            site.set_thread(std::thread(calculation_thread, cargs));
+            std::thread t([cargs](){
+                auto &site = *cargs->site;
+                site.interrupt();
+                site.wait();
+                site.start();
+                site.set_thread(std::thread(calculation_thread, cargs));
+            });
+            t.detach();
         }
         else
         {
@@ -76,6 +79,21 @@ namespace calcs {
     }
 }
 
+struct GIL_guard {
+    PyGILState_STATE state;
+    bool active;
+    GIL_guard():
+        state(PyGILState_Ensure()), active(true) {}
+    void restore()
+    {
+        PyGILState_Release(state);
+        active = false;
+    }
+    ~GIL_guard()
+    {
+        if (active) restore();
+    }
+};
 
 void * calculation_thread(calc_args *args)
 {
@@ -94,9 +112,8 @@ void * calculation_thread(calc_args *args)
 #ifdef DEBUG_THREADS
     std::cerr << args << " : CA : ENDCALC(" << std::this_thread::get_id() << ")\n";
 #endif
-    PyGILState_STATE gstate = PyGILState_Ensure();
+    GIL_guard e;
     delete args;
-    PyGILState_Release(gstate);
     return NULL;
 }
 
diff --git a/fract4d/c/fract4dmodule.cpp b/fract4d/c/fract4dmodule.cpp
index 2da6ba72c..5b1ca3f82 100644
--- a/fract4d/c/fract4dmodule.cpp
+++ b/fract4d/c/fract4dmodule.cpp
@@ -651,6 +651,7 @@ PyInit_fract4dc(void)
         return NULL;
     }
 
+    // todo: check this https://docs.python.org/3/c-api/init.html#c.PyEval_InitThreads
     PyEval_InitThreads();
 
     /* expose some constants */
1	From 3e3893b0ee381098418d7b28997f6b861c53eff1 Mon Sep 17 00:00:00 2001
2	From: Alberto Gonzalez <mindhells@gmail.com>
3	Date: Wed, 28 Oct 2020 09:44:09 +0000
4	Subject: [PATCH] fix #177: avoid GIL deadlock
5
6	---
7	fract4d/c/fract4dc/calcargs.cpp \| 8 --------
8	fract4d/c/fract4dc/calcs.cpp \| 31 ++++++++++++++++++++++++-------
9	fract4d/c/fract4dmodule.cpp \| 1 +
10	3 files changed, 25 insertions(+), 15 deletions(-)
11
12	diff --git a/fract4d/c/fract4dc/calcargs.cpp b/fract4d/c/fract4dc/calcargs.cpp
13	index 18eb83470..4296427da 100644
14	--- a/fract4d/c/fract4dc/calcargs.cpp
15	+++ b/fract4d/c/fract4dc/calcargs.cpp
16	@@ -1,5 +1,4 @@
17	#include "Python.h"
18	-#include <mutex>
19
20	#include "calcargs.h"
21
22	@@ -18,13 +17,10 @@ calc_args::calc_args()
23	params = new double[N_PARAMS];
24	}
25
26	-static std::mutex ref_count_mutex;
27	-
28	void calc_args::set_cmap(PyObject *pycmap_)
29	{
30	pycmap = pycmap_;
31	cmap = colormaps::cmap_fromcapsule(pycmap);
32	- const std::lock_guard<std::mutex> lock(ref_count_mutex);
33	Py_XINCREF(pycmap);
34	}
35
36	@@ -32,7 +28,6 @@ void calc_args::set_pfo(PyObject *pypfo_)
37	{
38	pypfo = pypfo_;
39	pfo = (loaders::pf_fromcapsule(pypfo))->pfo;
40	- const std::lock_guard<std::mutex> lock(ref_count_mutex);
41	Py_XINCREF(pypfo);
42	}
43
44	@@ -40,14 +35,12 @@ void calc_args::set_im(PyObject *pyim_)
45	{
46	pyim = pyim_;
47	im = images::image_fromcapsule(pyim);
48	- const std::lock_guard<std::mutex> lock(ref_count_mutex);
49	Py_XINCREF(pyim);
50	}
51	void calc_args::set_site(PyObject *pysite_)
52	{
53	pysite = pysite_;
54	site = sites::site_fromcapsule(pysite);
55	- const std::lock_guard<std::mutex> lock(ref_count_mutex);
56	Py_XINCREF(pysite);
57	}
58
59	@@ -57,7 +50,6 @@ calc_args::~calc_args()
60	#ifdef DEBUG_CREATION
61	fprintf(stderr, "%p : CA : DTOR\n", this);
62	#endif
63	- const std::lock_guard<std::mutex> lock(ref_count_mutex);
64	Py_XDECREF(pycmap);
65	Py_XDECREF(pypfo);
66	Py_XDECREF(pyim);
67	diff --git a/fract4d/c/fract4dc/calcs.cpp b/fract4d/c/fract4dc/calcs.cpp
68	index 1509e8d99..4b9c9b0d3 100644
69	--- a/fract4d/c/fract4dc/calcs.cpp
70	+++ b/fract4d/c/fract4dc/calcs.cpp
71	@@ -46,11 +46,14 @@ namespace calcs {
72
73	if (cargs->asynchronous)
74	{
75	- auto &site = *cargs->site;
76	- site.interrupt();
77	- site.wait();
78	- site.start();
79	- site.set_thread(std::thread(calculation_thread, cargs));
80	+ std::thread t([cargs](){
81	+ auto &site = *cargs->site;
82	+ site.interrupt();
83	+ site.wait();
84	+ site.start();
85	+ site.set_thread(std::thread(calculation_thread, cargs));
86	+ });
87	+ t.detach();
88	}
89	else
90	{
91	@@ -76,6 +79,21 @@ namespace calcs {
92	}
93	}
94
95	+struct GIL_guard {
96	+ PyGILState_STATE state;
97	+ bool active;
98	+ GIL_guard():
99	+ state(PyGILState_Ensure()), active(true) {}
100	+ void restore()
101	+ {
102	+ PyGILState_Release(state);
103	+ active = false;
104	+ }
105	+ ~GIL_guard()
106	+ {
107	+ if (active) restore();
108	+ }
109	+};
110
111	void * calculation_thread(calc_args *args)
112	{
113	@@ -94,9 +112,8 @@ void * calculation_thread(calc_args *args)
114	#ifdef DEBUG_THREADS
115	std::cerr << args << " : CA : ENDCALC(" << std::this_thread::get_id() << ")\n";
116	#endif
117	- PyGILState_STATE gstate = PyGILState_Ensure();
118	+ GIL_guard e;
119	delete args;
120	- PyGILState_Release(gstate);
121	return NULL;
122	}
123
124	diff --git a/fract4d/c/fract4dmodule.cpp b/fract4d/c/fract4dmodule.cpp
125	index 2da6ba72c..5b1ca3f82 100644
126	--- a/fract4d/c/fract4dmodule.cpp
127	+++ b/fract4d/c/fract4dmodule.cpp
128	@@ -651,6 +651,7 @@ PyInit_fract4dc(void)
129	return NULL;
130	}
131
132	+ // todo: check this https://docs.python.org/3/c-api/init.html#c.PyEval_InitThreads
133	PyEval_InitThreads();
134
135	/* expose some constants */