blob: 57bd093de17d3fda28e8e3a565de5ccd943a6f5e (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
/* Single-thread optimization definitions. Linux version.
Copyright (C) 2017 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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <tls.h>
#include <nptl/pthreadP.h>
/* The default way to check if the process is single thread is by using the
pthread_t 'multiple_threads' field. However for some architectures it
is faster to either use an extra field on TCB or global varibles
(the TCB field is also used on x86 for some single-thread atomic
optimizations).
The ABI might define SINGLE_THREAD_BY_GLOBAL to enable the single
thread check to use global variables instead of the pthread_t
field. */
#ifdef SINGLE_THREAD_BY_GLOBAL
# if IS_IN (libc)
extern int __libc_multiple_threads;
# define SINGLE_THREAD_P \
__glibc_likely (__libc_multiple_threads == 0)
# elif IS_IN (libpthread)
extern int __pthread_multiple_threads;
# define SINGLE_THREAD_P \
__glibc_likely (__pthread_multiple_threads == 0)
# elif IS_IN (librt)
# define SINGLE_THREAD_P \
__glibc_likely (THREAD_GETMEM (THREAD_SELF, \
header.multiple_threads) == 0)
# else
/* For rtld, et cetera. */
# define SINGLE_THREAD_P (1)
# endif
#else /* SINGLE_THREAD_BY_GLOBAL */
# if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
# define SINGLE_THREAD_P \
__glibc_likely (THREAD_GETMEM (THREAD_SELF, \
header.multiple_threads) == 0)
# else
/* For rtld, et cetera. */
# define SINGLE_THREAD_P (1)
# endif
#endif /* SINGLE_THREAD_BY_GLOBAL */
#define RTLD_SINGLE_THREAD_P \
__glibc_likely (THREAD_GETMEM (THREAD_SELF, \
header.multiple_threads) == 0)
|
