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Add single-thread.h header

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This patch move the single-thread syscall optimization defintions from
syscall-cancel.h to new header file single-thread.h and also move the
cancellation definitions from pthreadP.h to syscall-cancel.h.

The idea is just simplify the inclusion of both syscall-cancel.h and
single-thread.h (without the requirement of including all pthreadP.h
defintions).

No semantic changes expected, checked on a build for all major ABIs.

	* nptl/pthreadP.h (CANCEL_ASYNC, CANCEL_RESET, LIBC_CANCEL_ASYNC,
	LIBC_CANCEL_RESET, __libc_enable_asynccancel,
	__libc_disable_asynccancel, __librt_enable_asynccancel,
	__libc_disable_asynccancel, __librt_enable_asynccancel,
	__librt_disable_asynccancel): Move to ...
	* sysdeps/unix/sysv/linux/sysdep-cancel.h: ... here.
	(SINGLE_THREAD_P, RTLD_SINGLE_THREAD_P): Move to ...
	* sysdeps/unix/sysv/linux/single-thread.h: ... here.
	* sysdeps/generic/single-thread.h: New file.
	* sysdeps/unix/sysdep.h: Include single-thread.h.
	* sysdeps/unix/sysv/linux/futex-internal.h: Include sysdep-cancel.h.
	* sysdeps/unix/sysv/linux/lowlevellock-futex.h: Likewise.
This commit is contained in:
Adhemerval Zanella
2019-02-21 14:33:55 -03:00
parent f6efec90c8
commit fdb8a0be9b
8 changed files with 146 additions and 79 deletions
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62
sysdeps/unix/sysv/linux/single-thread.h Normal file
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/* Single thread optimization, Linux version.
Copyright (C) 2019 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/>. */
#ifndef _SINGLE_THREAD_H
#define _SINGLE_THREAD_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 variables (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)
#endif /* _SINGLE_THREAD_H */