Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Appearance settings

Commit 3e25a93

Browse filesBrowse files
zackwzackw
committed
Take advantage of PyErr_CheckSignals now being callable without the GIL.
The source tree contains dozens of loops of this form: int res; do { Py_BEGIN_ALLOW_THREADS res = some_system_call(arguments...); Py_END_ALLOW_THREADS } while (res < 0 && errno == EINTR && !PyErr_CheckSignals()); Now that it is possible to call PyErr_CheckSignals without holding the GIL, the locking operations can be moved out of the loop: Py_BEGIN_ALLOW_THREADS do { res = some_system_call(arguments...); } while (res < 0 && errno == EINTR && !PyErr_CheckSignals()); Py_END_ALLOW_THREADS This demonstrates the motivation for making it possible to call PyErr_CheckSignals without holding the GIL. It shouldn’t make any measurable difference performance-wise for _these_ loops, which almost never actually cycle; but for loops that do cycle many times it’s very much desirable to not take and release the GIL every time through. In some cases I also moved uses of _Py_(BEGIN|END)_SUPPRESS_IPH, which is often paired with Py_(BEGIN|END)_ALLOW_THREADS, to keep the pairing intact. It was already considered safe to call PyErr_CheckSignals from both inside and outside an IPH suppression region. More could be done in this vein: I didn’t change any loops where the inside of the loop was more complicated than a single system call, _except_ that I did refactor py_getentropy and py_getrandom (in bootstrap_hash.c) to make it possible to move the unlock and lock outside the loop, demonstrating a more complicated case.
1 parent c0f5de9 commit 3e25a93
Copy full SHA for 3e25a93

File tree

11 files changed

+167
-191
lines changed
Filter options

11 files changed

+167
-191
lines changed

‎Modules/_io/fileio.c

Copy file name to clipboardExpand all lines: Modules/_io/fileio.c
+2-2Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -403,16 +403,16 @@ _io_FileIO___init___impl(fileio *self, PyObject *nameobj, const char *mode,
403403

404404
errno = 0;
405405
if (opener == Py_None) {
406+
Py_BEGIN_ALLOW_THREADS
406407
do {
407-
Py_BEGIN_ALLOW_THREADS
408408
#ifdef MS_WINDOWS
409409
self->fd = _wopen(widename, flags, 0666);
410410
#else
411411
self->fd = open(name, flags, 0666);
412412
#endif
413-
Py_END_ALLOW_THREADS
414413
} while (self->fd < 0 && errno == EINTR &&
415414
!(async_err = PyErr_CheckSignals()));
415+
Py_END_ALLOW_THREADS
416416

417417
if (async_err)
418418
goto error;

‎Modules/_io/winconsoleio.c

Copy file name to clipboardExpand all lines: Modules/_io/winconsoleio.c
-2Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -647,9 +647,7 @@ read_console_w(HANDLE handle, DWORD maxlen, DWORD *readlen) {
647647
if (WaitForSingleObjectEx(hInterruptEvent, 100, FALSE)
648648
== WAIT_OBJECT_0) {
649649
ResetEvent(hInterruptEvent);
650-
Py_BLOCK_THREADS
651650
sig = PyErr_CheckSignals();
652-
Py_UNBLOCK_THREADS
653651
if (sig < 0)
654652
break;
655653
}

‎Modules/_multiprocessing/posixshmem.c

Copy file name to clipboardExpand all lines: Modules/_multiprocessing/posixshmem.c
+4-4Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -57,11 +57,11 @@ _posixshmem_shm_open_impl(PyObject *module, PyObject *path, int flags,
5757
PyErr_SetString(PyExc_ValueError, "embedded null character");
5858
return -1;
5959
}
60+
Py_BEGIN_ALLOW_THREADS
6061
do {
61-
Py_BEGIN_ALLOW_THREADS
6262
fd = shm_open(name, flags, mode);
63-
Py_END_ALLOW_THREADS
6463
} while (fd < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
64+
Py_END_ALLOW_THREADS
6565

6666
if (fd < 0) {
6767
if (!async_err)
@@ -102,11 +102,11 @@ _posixshmem_shm_unlink_impl(PyObject *module, PyObject *path)
102102
PyErr_SetString(PyExc_ValueError, "embedded null character");
103103
return NULL;
104104
}
105+
Py_BEGIN_ALLOW_THREADS
105106
do {
106-
Py_BEGIN_ALLOW_THREADS
107107
rv = shm_unlink(name);
108-
Py_END_ALLOW_THREADS
109108
} while (rv < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
109+
Py_END_ALLOW_THREADS
110110

111111
if (rv < 0) {
112112
if (!async_err)

‎Modules/_multiprocessing/semaphore.c

Copy file name to clipboardExpand all lines: Modules/_multiprocessing/semaphore.c
+2-2Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -356,19 +356,19 @@ _multiprocessing_SemLock_acquire_impl(SemLockObject *self, int blocking,
356356

357357
if (res < 0 && errno == EAGAIN && blocking) {
358358
/* Couldn't acquire immediately, need to block */
359+
Py_BEGIN_ALLOW_THREADS
359360
do {
360-
Py_BEGIN_ALLOW_THREADS
361361
if (!use_deadline) {
362362
res = sem_wait(self->handle);
363363
}
364364
else {
365365
res = sem_timedwait(self->handle, &deadline);
366366
}
367-
Py_END_ALLOW_THREADS
368367
err = errno;
369368
if (res == MP_EXCEPTION_HAS_BEEN_SET)
370369
break;
371370
} while (res < 0 && errno == EINTR && !PyErr_CheckSignals());
371+
Py_END_ALLOW_THREADS
372372
}
373373

374374
if (res < 0) {

‎Modules/fcntlmodule.c

Copy file name to clipboardExpand all lines: Modules/fcntlmodule.c
+16-16Lines changed: 16 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -73,11 +73,11 @@ fcntl_fcntl_impl(PyObject *module, int fd, int code, PyObject *arg)
7373
}
7474
}
7575

76+
Py_BEGIN_ALLOW_THREADS
7677
do {
77-
Py_BEGIN_ALLOW_THREADS
7878
ret = fcntl(fd, code, (int)int_arg);
79-
Py_END_ALLOW_THREADS
8079
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
80+
Py_END_ALLOW_THREADS
8181
if (ret < 0) {
8282
return !async_err ? PyErr_SetFromErrno(PyExc_OSError) : NULL;
8383
}
@@ -103,11 +103,11 @@ fcntl_fcntl_impl(PyObject *module, int fd, int code, PyObject *arg)
103103
memcpy(buf + len, guard, GUARDSZ);
104104
PyBuffer_Release(&view);
105105

106+
Py_BEGIN_ALLOW_THREADS
106107
do {
107-
Py_BEGIN_ALLOW_THREADS
108108
ret = fcntl(fd, code, buf);
109-
Py_END_ALLOW_THREADS
110109
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
110+
Py_END_ALLOW_THREADS
111111
if (ret < 0) {
112112
return !async_err ? PyErr_SetFromErrno(PyExc_OSError) : NULL;
113113
}
@@ -195,11 +195,11 @@ fcntl_ioctl_impl(PyObject *module, int fd, unsigned long code, PyObject *arg,
195195
}
196196
}
197197

198+
Py_BEGIN_ALLOW_THREADS
198199
do {
199-
Py_BEGIN_ALLOW_THREADS
200200
ret = ioctl(fd, code, int_arg);
201-
Py_END_ALLOW_THREADS
202201
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
202+
Py_END_ALLOW_THREADS
203203
if (ret < 0) {
204204
return !async_err ? PyErr_SetFromErrno(PyExc_OSError) : NULL;
205205
}
@@ -219,11 +219,11 @@ fcntl_ioctl_impl(PyObject *module, int fd, unsigned long code, PyObject *arg,
219219
memcpy(buf + len, guard, GUARDSZ);
220220
ptr = buf;
221221
}
222+
Py_BEGIN_ALLOW_THREADS
222223
do {
223-
Py_BEGIN_ALLOW_THREADS
224224
ret = ioctl(fd, code, ptr);
225-
Py_END_ALLOW_THREADS
226225
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
226+
Py_END_ALLOW_THREADS
227227
if (ret < 0) {
228228
if (!async_err) {
229229
PyErr_SetFromErrno(PyExc_OSError);
@@ -261,11 +261,11 @@ fcntl_ioctl_impl(PyObject *module, int fd, unsigned long code, PyObject *arg,
261261
memcpy(buf + len, guard, GUARDSZ);
262262
PyBuffer_Release(&view);
263263

264+
Py_BEGIN_ALLOW_THREADS
264265
do {
265-
Py_BEGIN_ALLOW_THREADS
266266
ret = ioctl(fd, code, buf);
267-
Py_END_ALLOW_THREADS
268267
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
268+
Py_END_ALLOW_THREADS
269269
if (ret < 0) {
270270
return !async_err ? PyErr_SetFromErrno(PyExc_OSError) : NULL;
271271
}
@@ -308,11 +308,11 @@ fcntl_flock_impl(PyObject *module, int fd, int code)
308308
}
309309

310310
#ifdef HAVE_FLOCK
311+
Py_BEGIN_ALLOW_THREADS
311312
do {
312-
Py_BEGIN_ALLOW_THREADS
313313
ret = flock(fd, code);
314-
Py_END_ALLOW_THREADS
315314
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
315+
Py_END_ALLOW_THREADS
316316
#else
317317

318318
#ifndef LOCK_SH
@@ -335,11 +335,11 @@ fcntl_flock_impl(PyObject *module, int fd, int code)
335335
return NULL;
336336
}
337337
l.l_whence = l.l_start = l.l_len = 0;
338+
Py_BEGIN_ALLOW_THREADS
338339
do {
339-
Py_BEGIN_ALLOW_THREADS
340340
ret = fcntl(fd, (code & LOCK_NB) ? F_SETLK : F_SETLKW, &l);
341-
Py_END_ALLOW_THREADS
342341
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
342+
Py_END_ALLOW_THREADS
343343
}
344344
#endif /* HAVE_FLOCK */
345345
if (ret < 0) {
@@ -439,11 +439,11 @@ fcntl_lockf_impl(PyObject *module, int fd, int code, PyObject *lenobj,
439439
return NULL;
440440
}
441441
l.l_whence = whence;
442+
Py_BEGIN_ALLOW_THREADS
442443
do {
443-
Py_BEGIN_ALLOW_THREADS
444444
ret = fcntl(fd, (code & LOCK_NB) ? F_SETLK : F_SETLKW, &l);
445-
Py_END_ALLOW_THREADS
446445
} while (ret == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
446+
Py_END_ALLOW_THREADS
447447
}
448448
if (ret < 0) {
449449
return !async_err ? PyErr_SetFromErrno(PyExc_OSError) : NULL;

0 commit comments

Comments
0 (0)
Morty Proxy This is a proxified and sanitized view of the page, visit original site.