c7cffa0722
The atomic compare-and-swap can be used to implement lock-free structures. The planned use for this is to remove some of the locking done in the services when listeners are being manipulated.
137 lines
3.3 KiB
C++
137 lines
3.3 KiB
C++
/*
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* Copyright (c) 2016 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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*
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* Change Date: 2019-07-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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#include <maxscale/atomic.h>
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/**
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* @file atomic.c - Implementation of atomic operations for MaxScale
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*/
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int atomic_add(int *variable, int value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_fetch_add(variable, value, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_add(variable, value);
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#endif
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}
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uint32_t atomic_add_uint32(uint32_t *variable, int32_t value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_fetch_add(variable, value, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_add(variable, value);
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#endif
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}
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int64_t atomic_add_int64(int64_t *variable, int64_t value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_fetch_add(variable, value, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_add(variable, value);
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#endif
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}
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uint64_t atomic_add_uint64(uint64_t *variable, int64_t value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_fetch_add(variable, value, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_add(variable, value);
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#endif
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}
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int atomic_load_int32(int *variable)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_load_n(variable, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_or(variable, 0);
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#endif
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}
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int64_t atomic_load_int64(int64_t *variable)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_load_n(variable, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_or(variable, 0);
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#endif
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}
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uint64_t atomic_load_uint64(uint64_t *variable)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_load_n(variable, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_or(variable, 0);
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#endif
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}
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void* atomic_load_ptr(void **variable)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_load_n(variable, __ATOMIC_SEQ_CST);
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#else
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return __sync_fetch_and_or(variable, 0);
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#endif
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}
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void atomic_store_int32(int *variable, int value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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__atomic_store_n(variable, value, __ATOMIC_SEQ_CST);
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#else
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(void)__sync_lock_test_and_set(variable, value);
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#endif
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}
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void atomic_store_int64(int64_t *variable, int64_t value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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__atomic_store_n(variable, value, __ATOMIC_SEQ_CST);
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#else
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(void)__sync_lock_test_and_set(variable, value);
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#endif
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}
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void atomic_store_uint64(uint64_t *variable, uint64_t value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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__atomic_store_n(variable, value, __ATOMIC_SEQ_CST);
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#else
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(void)__sync_lock_test_and_set(variable, value);
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#endif
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}
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void atomic_store_ptr(void **variable, void *value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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__atomic_store_n(variable, value, __ATOMIC_SEQ_CST);
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#else
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(void)__sync_lock_test_and_set(variable, value);
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#endif
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}
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bool atomic_cas_ptr(void **variable, void** old_value, void *new_value)
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{
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#ifdef MXS_USE_ATOMIC_BUILTINS
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return __atomic_compare_exchange_n(variable, old_value, new_value,
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false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
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#else
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return __sync_val_compare_and_swap(variable, *old_value, new_value);
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#endif
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}
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