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e59660bc25
* tst-initializers1.c: Show through exit code which test failed. * pthread_rwlock_init.c: Also initialize __shared field. * sysdeps/unix/sysv/linux/i386/bits/pthreadtypes.h: Split __flags element in rwlock structure into four byte elements. One of them is the new __shared element. * sysdeps/unix/sysv/linux/x86_64/bits/pthreadtypes.h [__WORDSIZE=32]: Likewise. [__WORDSIZE=64]: Renamed __pad1 element int rwlock structire to __shared, adjust names of other padding elements. * sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h: Likewise. * sysdeps/pthread/pthread.h: Adjust rwlock initializers. * sysdeps/unix/sysv/linux/lowlevelrwlock.sym: Add PSHARED. * sysdeps/unix/sysv/linux/powerpc/lowlevellock.h: Define FUTEX_PRIVATE_FLAG. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_rdlock.S: Change main futex to use private operations if possible. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_timedrdlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_timedwrlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_unlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_wrlock.S: Likewise.
83 lines
2.9 KiB
C
83 lines
2.9 KiB
C
/* Copyright (C) 2002, 2007 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include "pthreadP.h"
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#include <kernel-features.h>
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static const struct pthread_rwlockattr default_attr =
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{
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.lockkind = PTHREAD_RWLOCK_DEFAULT_NP,
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.pshared = PTHREAD_PROCESS_PRIVATE
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};
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int
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__pthread_rwlock_init (rwlock, attr)
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pthread_rwlock_t *rwlock;
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const pthread_rwlockattr_t *attr;
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{
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const struct pthread_rwlockattr *iattr;
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iattr = ((const struct pthread_rwlockattr *) attr) ?: &default_attr;
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rwlock->__data.__lock = 0;
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rwlock->__data.__nr_readers = 0;
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rwlock->__data.__readers_wakeup = 0;
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rwlock->__data.__writer_wakeup = 0;
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rwlock->__data.__nr_readers_queued = 0;
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rwlock->__data.__nr_writers_queued = 0;
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rwlock->__data.__writer = 0;
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rwlock->__data.__flags
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= iattr->lockkind == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP;
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/* The __SHARED field is computed to minimize the work that needs to
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be done while handling the futex. There are two inputs: the
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availability of private futexes and whether the rwlock is shared
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or private. Unfortunately the value of a private rwlock is
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fixed: it must be zero. The PRIVATE_FUTEX flag has the value
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0x80 in case private futexes are available and zero otherwise.
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This leads to the following table:
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| pshared | result
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| shared private | shared private |
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------------+-----------------+-----------------+
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!avail 0 | 0 0 | 0 0 |
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avail 0x80 | 0x80 0 | 0 0x80 |
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If the pshared value is in locking functions XORed with avail
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we get the expected result. */
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#ifdef __ASSUME_PRIVATE_FUTEX
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rwlock->__data.__shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE
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? 0 : FUTEX_PRIVATE_FLAG);
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#else
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rwlock->__data.__shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE
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? 0
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: THREAD_GETMEM (THREAD_SELF,
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header.private_futex));
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#endif
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rwlock->__data.__pad1 = 0;
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rwlock->__data.__pad2 = 0;
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return 0;
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}
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strong_alias (__pthread_rwlock_init, pthread_rwlock_init)
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