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* init.c: Make it compile with older kernel headers.

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* 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.
This commit is contained in:
Ulrich Drepper
2007-05-27 18:06:18 +00:00
parent 546346b6f8
commit e59660bc25
12 changed files with 120 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
nptl/pthread_rwlock_init.c
View File

@ -1,4 +1,4 @@
/* Copyright (C) 2002 Free Software Foundation, Inc.
/* Copyright (C) 2002, 2007 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
@ -18,6 +18,7 @@
02111-1307 USA. */
#include "pthreadP.h"
#include <kernel-features.h>
static const struct pthread_rwlockattr default_attr =
@ -37,14 +38,44 @@ __pthread_rwlock_init (rwlock, attr)
iattr = ((const struct pthread_rwlockattr *) attr) ?: &default_attr;
rwlock->__data.__lock = 0;
rwlock->__data.__flags
= iattr->lockkind == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP;
rwlock->__data.__nr_readers = 0;
rwlock->__data.__writer = 0;
rwlock->__data.__readers_wakeup = 0;
rwlock->__data.__writer_wakeup = 0;
rwlock->__data.__nr_readers_queued = 0;
rwlock->__data.__nr_writers_queued = 0;
rwlock->__data.__writer = 0;
rwlock->__data.__flags
= iattr->lockkind == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP;
/* The __SHARED field is computed to minimize the work that needs to
be done while handling the futex. There are two inputs: the
availability of private futexes and whether the rwlock is shared
or private. Unfortunately the value of a private rwlock is
fixed: it must be zero. The PRIVATE_FUTEX flag has the value
0x80 in case private futexes are available and zero otherwise.
This leads to the following table:
| pshared | result
| shared private | shared private |
------------+-----------------+-----------------+
!avail 0 | 0 0 | 0 0 |
avail 0x80 | 0x80 0 | 0 0x80 |
If the pshared value is in locking functions XORed with avail
we get the expected result. */
#ifdef __ASSUME_PRIVATE_FUTEX
rwlock->__data.__shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE
? 0 : FUTEX_PRIVATE_FLAG);
#else
rwlock->__data.__shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE
? 0
: THREAD_GETMEM (THREAD_SELF,
header.private_futex));
#endif
rwlock->__data.__pad1 = 0;
rwlock->__data.__pad2 = 0;
return 0;
}