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The support for lock elision was already deprecated with glibc 2.42: commit77438db8cf"Mark support for lock elision as deprecated." See also discussions: https://sourceware.org/pipermail/libc-alpha/2025-July/168492.html This patch removes the architecture specific support for lock elision for x86, powerpc and s390 by removing the elision-conf.h, elision-conf.c, elision-lock.c, elision-timed.c, elision-unlock.c, elide.h, htm.h/hle.h files. Those generic files are also removed. The architecture specific structures are adjusted and the elision fields are marked as unused. See struct_mutex.h files. Furthermore in struct_rwlock.h, the leftover __rwelision was also removed. Those were originally removed with commit0377a7fde6"nptl: Remove rwlock elision definitions" and by chance reintroduced with commit7df8af43ad"nptl: Add struct_rwlock.h" The common code (e.g. the pthread_mutex-files) are changed back to the time before lock elision was introduced with the x86-support: - commit1cdbe57948"Add the low level infrastructure for pthreads lock elision with TSX" - commitb023e4ca99"Add new internal mutex type flags for elision." - commit68cc29355f"Add minimal test suite changes for elision enabled kernels" - commite8c659d74e"Add elision to pthread_mutex_{try,timed,un}lock" - commit49186d21ef"Disable elision for any pthread_mutexattr_settype call" - commit1717da59ae"Add a configure option to enable lock elision and disable by default" Elision is removed also from the tunables, the initialization part, the pretty-printers and the manual. Some extra handling in the testsuite is removed as well as the full tst-mutex10 testcase, which tested a race while enabling lock elision. I've also searched the code for "elision", "elide", "transaction" and e.g. cleaned some comments. I've run the testsuite on x86_64 and s390x and run the build-many-glibcs.py script. Thanks to Sachin Monga, this patch is also tested on powerpc. A NEWS entry also mentions the removal. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
71 lines
2.2 KiB
C
71 lines
2.2 KiB
C
/* Default mutex implementation struct definitions.
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Copyright (C) 2019-2025 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _THREAD_MUTEX_INTERNAL_H
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#define _THREAD_MUTEX_INTERNAL_H 1
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/* Generic struct for both POSIX and C11 mutexes. New ports are expected
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to use the default layout, however architecture can redefine it to
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add arch-specific extension. The struct have a size of 32 bytes on LP32
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and 40 bytes on LP64 architectures. */
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struct __pthread_mutex_s
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{
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int __lock __LOCK_ALIGNMENT;
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unsigned int __count;
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int __owner;
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#if __WORDSIZE == 64
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unsigned int __nusers;
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#endif
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/* KIND must stay at this position in the structure to maintain
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binary compatibility with static initializers.
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Concurrency notes:
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The __kind of a mutex is initialized either by the static
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PTHREAD_MUTEX_INITIALIZER or by a call to pthread_mutex_init.
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After a mutex has been initialized, the __kind of a mutex is usually not
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changed. BUT it can be set to -1 in pthread_mutex_destroy. */
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int __kind;
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#if __WORDSIZE != 64
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unsigned int __nusers;
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#endif
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#if __WORDSIZE == 64
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int __spins;
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__pthread_list_t __list;
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# define __PTHREAD_MUTEX_HAVE_PREV 1
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#else
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__extension__ union
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{
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int __spins;
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__pthread_slist_t __list;
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};
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# define __PTHREAD_MUTEX_HAVE_PREV 0
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#endif
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};
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#if __PTHREAD_MUTEX_HAVE_PREV == 1
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# define __PTHREAD_MUTEX_INITIALIZER(__kind) \
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0, 0, 0, 0, __kind, 0, { 0, 0 }
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#else
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# define __PTHREAD_MUTEX_INITIALIZER(__kind) \
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0, 0, 0, __kind, 0, { 0 }
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#endif
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#endif
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