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100 lines
4.1 KiB
C
100 lines
4.1 KiB
C
#ifndef ATOMIC_RWLOCK_INCLUDED
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#define ATOMIC_RWLOCK_INCLUDED
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/* Copyright (C) 2006 MySQL AB, 2009 Sun Microsystems, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#define MY_ATOMIC_MODE_RWLOCKS 1
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#ifdef MY_ATOMIC_MODE_DUMMY
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/*
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the following can never be enabled by ./configure, one need to put #define in
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a source to trigger the following warning. The resulting code will be broken,
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it only makes sense to do it to see now test_atomic detects broken
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implementations (another way is to run a UP build on an SMP box).
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*/
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#warning MY_ATOMIC_MODE_DUMMY and MY_ATOMIC_MODE_RWLOCKS are incompatible
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typedef char my_atomic_rwlock_t;
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#define my_atomic_rwlock_destroy(name)
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#define my_atomic_rwlock_init(name)
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#define my_atomic_rwlock_rdlock(name)
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#define my_atomic_rwlock_wrlock(name)
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#define my_atomic_rwlock_rdunlock(name)
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#define my_atomic_rwlock_wrunlock(name)
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#define MY_ATOMIC_MODE "dummy (non-atomic)"
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#else /* not MY_ATOMIC_MODE_DUMMY */
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typedef struct {pthread_mutex_t rw;} my_atomic_rwlock_t;
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#ifndef SAFE_MUTEX
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/*
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we're using read-write lock macros but map them to mutex locks, and they're
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faster. Still, having semantically rich API we can change the
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underlying implementation, if necessary.
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*/
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#define my_atomic_rwlock_destroy(name) pthread_mutex_destroy(& (name)->rw)
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#define my_atomic_rwlock_init(name) pthread_mutex_init(& (name)->rw, 0)
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#define my_atomic_rwlock_rdlock(name) pthread_mutex_lock(& (name)->rw)
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#define my_atomic_rwlock_wrlock(name) pthread_mutex_lock(& (name)->rw)
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#define my_atomic_rwlock_rdunlock(name) pthread_mutex_unlock(& (name)->rw)
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#define my_atomic_rwlock_wrunlock(name) pthread_mutex_unlock(& (name)->rw)
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#else /* SAFE_MUTEX */
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/*
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SAFE_MUTEX pollutes the compiling name space with macros
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that alter pthread_mutex_t, pthread_mutex_init, etc.
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Atomic operations should never use the safe mutex wrappers.
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Unfortunately, there is no way to have both:
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- safe mutex macros expanding pthread_mutex_lock to safe_mutex_lock
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- my_atomic macros expanding to unmodified pthread_mutex_lock
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inlined in the same compilation unit.
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So, in case of SAFE_MUTEX, a function call is required.
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Given that SAFE_MUTEX is a debugging facility,
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this extra function call is not a performance concern for
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production builds.
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*/
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C_MODE_START
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extern void plain_pthread_mutex_init(safe_mutex_t *);
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extern void plain_pthread_mutex_destroy(safe_mutex_t *);
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extern void plain_pthread_mutex_lock(safe_mutex_t *);
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extern void plain_pthread_mutex_unlock(safe_mutex_t *);
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C_MODE_END
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#define my_atomic_rwlock_destroy(name) plain_pthread_mutex_destroy(&(name)->rw)
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#define my_atomic_rwlock_init(name) plain_pthread_mutex_init(&(name)->rw)
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#define my_atomic_rwlock_rdlock(name) plain_pthread_mutex_lock(&(name)->rw)
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#define my_atomic_rwlock_wrlock(name) plain_pthread_mutex_lock(&(name)->rw)
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#define my_atomic_rwlock_rdunlock(name) plain_pthread_mutex_unlock(&(name)->rw)
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#define my_atomic_rwlock_wrunlock(name) plain_pthread_mutex_unlock(&(name)->rw)
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#endif /* SAFE_MUTEX */
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#define MY_ATOMIC_MODE "mutex"
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#ifndef MY_ATOMIC_MODE_RWLOCKS
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#define MY_ATOMIC_MODE_RWLOCKS 1
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#endif
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#endif
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#define make_atomic_add_body(S) int ## S sav; sav= *a; *a+= v; v=sav;
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#define make_atomic_fas_body(S) int ## S sav; sav= *a; *a= v; v=sav;
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#define make_atomic_cas_body(S) if ((ret= (*a == *cmp))) *a= set; else *cmp=*a;
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#define make_atomic_load_body(S) ret= *a;
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#define make_atomic_store_body(S) *a= v;
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#endif /* ATOMIC_RWLOCK_INCLUDED */
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