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	This replaces the pthread rwlock with a new implementation that uses a more scalable algorithm (primarily through not using a critical section anymore to make state changes). The fast path for rdlock acquisition and release is now basically a single atomic read-modify write or CAS and a few branches. See nptl/pthread_rwlock_common.c for details. * nptl/DESIGN-rwlock.txt: Remove. * nptl/lowlevelrwlock.sym: Remove. * nptl/Makefile: Add new tests. * nptl/pthread_rwlock_common.c: New file. Contains the new rwlock. * nptl/pthreadP.h (PTHREAD_RWLOCK_PREFER_READER_P): Remove. (PTHREAD_RWLOCK_WRPHASE, PTHREAD_RWLOCK_WRLOCKED, PTHREAD_RWLOCK_RWAITING, PTHREAD_RWLOCK_READER_SHIFT, PTHREAD_RWLOCK_READER_OVERFLOW, PTHREAD_RWLOCK_WRHANDOVER, PTHREAD_RWLOCK_FUTEX_USED): New. * nptl/pthread_rwlock_init.c (__pthread_rwlock_init): Adapt to new implementation. * nptl/pthread_rwlock_rdlock.c (__pthread_rwlock_rdlock_slow): Remove. (__pthread_rwlock_rdlock): Adapt. * nptl/pthread_rwlock_timedrdlock.c (pthread_rwlock_timedrdlock): Adapt. * nptl/pthread_rwlock_timedwrlock.c (pthread_rwlock_timedwrlock): Adapt. * nptl/pthread_rwlock_trywrlock.c (pthread_rwlock_trywrlock): Adapt. * nptl/pthread_rwlock_tryrdlock.c (pthread_rwlock_tryrdlock): Adapt. * nptl/pthread_rwlock_unlock.c (pthread_rwlock_unlock): Adapt. * nptl/pthread_rwlock_wrlock.c (__pthread_rwlock_wrlock_slow): Remove. (__pthread_rwlock_wrlock): Adapt. * nptl/tst-rwlock10.c: Adapt. * nptl/tst-rwlock11.c: Adapt. * nptl/tst-rwlock17.c: New file. * nptl/tst-rwlock18.c: New file. * nptl/tst-rwlock19.c: New file. * nptl/tst-rwlock2b.c: New file. * nptl/tst-rwlock8.c: Adapt. * nptl/tst-rwlock9.c: Adapt. * sysdeps/aarch64/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/arm/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/hppa/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/ia64/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/m68k/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/microblaze/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/mips/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/nios2/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/s390/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/sh/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/sparc/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/tile/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/unix/sysv/linux/alpha/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * sysdeps/x86/bits/pthreadtypes.h (pthread_rwlock_t): Adapt. * nptl/nptl-printers.py (): Adapt. * nptl/nptl_lock_constants.pysym: Adapt. * nptl/test-rwlock-printers.py: Adapt. * nptl/test-rwlockattr-printers.c: Adapt. * nptl/test-rwlockattr-printers.py: Adapt.
		
			
				
	
	
		
			101 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			101 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* Helper program for testing the pthread_rwlock_t and pthread_rwlockattr_t
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|    pretty printers.
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| 
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|    Copyright (C) 2016-2017 Free Software Foundation, Inc.
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|    This file is part of the GNU C Library.
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| 
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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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| 
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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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| 
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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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| 
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| /* Keep the calls to the pthread_* functions on separate lines to make it easy
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|    to advance through the program using the gdb 'next' command.  */
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| 
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| #include <pthread.h>
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| 
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| #define PASS 0
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| #define FAIL 1
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| 
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| /* Need these so we don't have lines longer than 79 chars.  */
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| #define SET_KIND(attr, kind) pthread_rwlockattr_setkind_np (attr, kind)
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| #define SET_SHARED(attr, shared) pthread_rwlockattr_setpshared (attr, shared)
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| 
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| static int rwlock_reinit (pthread_rwlock_t *rwlock,
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| 			  const pthread_rwlockattr_t *attr);
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| static int test_setkind_np (pthread_rwlock_t *rwlock,
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| 			    pthread_rwlockattr_t *attr);
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| static int test_setpshared (pthread_rwlock_t *rwlock,
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| 			    pthread_rwlockattr_t *attr);
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| 
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| int
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| main (void)
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| {
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|   pthread_rwlock_t rwlock;
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|   pthread_rwlockattr_t attr;
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|   int result = FAIL;
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| 
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|   if (pthread_rwlockattr_init (&attr) == 0
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|       && pthread_rwlock_init (&rwlock, NULL) == 0
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|       && test_setkind_np (&rwlock, &attr) == PASS
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|       && test_setpshared (&rwlock, &attr) == PASS)
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|     result = PASS;
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|   /* Else, one of the pthread_rwlock* functions failed.  */
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| 
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|   return result;
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| }
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| 
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| /* Destroys RWLOCK and re-initializes it using ATTR.  */
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| static int
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| rwlock_reinit (pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr)
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| {
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|   int result = FAIL;
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| 
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|   if (pthread_rwlock_destroy (rwlock) == 0
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|       && pthread_rwlock_init (rwlock, attr) == 0)
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|     result = PASS;
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| 
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|   return result;
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| }
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| 
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| /* Tests setting whether the rwlock prefers readers or writers.  */
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| static int
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| test_setkind_np (pthread_rwlock_t *rwlock, pthread_rwlockattr_t *attr)
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| {
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|   int result = FAIL;
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| 
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|   if (SET_KIND (attr, PTHREAD_RWLOCK_PREFER_READER_NP) == 0 /* Set kind.  */
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|       && rwlock_reinit (rwlock, attr) == PASS
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|       && SET_KIND (attr, PTHREAD_RWLOCK_PREFER_WRITER_NP) == 0
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|       && rwlock_reinit (rwlock, attr) == PASS
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|       && SET_KIND (attr, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP) == 0
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|       && rwlock_reinit (rwlock, attr) == PASS)
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|     result = PASS;
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| 
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|   return result;
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| }
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| 
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| /* Tests setting whether the rwlock can be shared between processes.  */
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| static int
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| test_setpshared (pthread_rwlock_t *rwlock, pthread_rwlockattr_t *attr)
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| {
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|   int result = FAIL;
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| 
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|   if (SET_SHARED (attr, PTHREAD_PROCESS_SHARED) == 0 /* Set shared.  */
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|       && rwlock_reinit (rwlock, attr) == PASS
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|       && SET_SHARED (attr, PTHREAD_PROCESS_PRIVATE) == 0
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|       && rwlock_reinit (rwlock, attr) == PASS)
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|     result = PASS;
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| 
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|   return result;
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| }
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