mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 04:50:07 +00:00
706ad1e7af
The variable is placed in libc.so, and it can be true only in an outer libc, not libcs loaded via dlmopen or static dlopen. Since thread creation from inner namespaces does not work, pthread_create can update __libc_single_threaded directly. Using __libc_early_init and its initial flag, implementation of this variable is very straightforward. A future version may reset the flag during fork (but not in an inner namespace), or after joining all threads except one. Reviewed-by: DJ Delorie <dj@redhat.com>
87 lines
2.6 KiB
C
87 lines
2.6 KiB
C
/* Test support for single-thread optimizations. With threads, static version.
|
|
Copyright (C) 2020 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
/* This test is a stripped-down version of
|
|
tst-single_threaded-pthread.c, without any loading of dynamic
|
|
objects. */
|
|
|
|
#include <stdio.h>
|
|
#include <support/check.h>
|
|
#include <support/xthread.h>
|
|
#include <sys/single_threaded.h>
|
|
|
|
/* First barrier synchronizes main thread, thread 1, thread 2. */
|
|
static pthread_barrier_t barrier1;
|
|
|
|
/* Second barrier synchronizes main thread, thread 2. */
|
|
static pthread_barrier_t barrier2;
|
|
|
|
static void *
|
|
threadfunc (void *closure)
|
|
{
|
|
TEST_VERIFY (!__libc_single_threaded);
|
|
|
|
/* Wait for the main thread and the other thread. */
|
|
xpthread_barrier_wait (&barrier1);
|
|
TEST_VERIFY (!__libc_single_threaded);
|
|
|
|
/* Second thread waits on second barrier, too. */
|
|
if (closure != NULL)
|
|
xpthread_barrier_wait (&barrier2);
|
|
TEST_VERIFY (!__libc_single_threaded);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static int
|
|
do_test (void)
|
|
{
|
|
TEST_VERIFY (__libc_single_threaded);
|
|
|
|
/* Two threads plus main thread. */
|
|
xpthread_barrier_init (&barrier1, NULL, 3);
|
|
|
|
/* Main thread and second thread. */
|
|
xpthread_barrier_init (&barrier2, NULL, 2);
|
|
|
|
pthread_t thr1 = xpthread_create (NULL, threadfunc, NULL);
|
|
TEST_VERIFY (!__libc_single_threaded);
|
|
|
|
pthread_t thr2 = xpthread_create (NULL, threadfunc, &thr2);
|
|
TEST_VERIFY (!__libc_single_threaded);
|
|
|
|
xpthread_barrier_wait (&barrier1);
|
|
TEST_VERIFY (!__libc_single_threaded);
|
|
|
|
/* Join first thread. This should not bring us back into
|
|
single-threaded mode. */
|
|
xpthread_join (thr1);
|
|
TEST_VERIFY (!__libc_single_threaded);
|
|
|
|
/* We may be back in single-threaded mode after joining both
|
|
threads, but this is not guaranteed. */
|
|
xpthread_barrier_wait (&barrier2);
|
|
xpthread_join (thr2);
|
|
printf ("info: __libc_single_threaded after joining all threads: %d\n",
|
|
__libc_single_threaded);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#include <support/test-driver.c>
|