103 lines
3.7 KiB
C++
103 lines
3.7 KiB
C++
/*
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Copyright (c) 2005-2017 Intel Corporation
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#ifndef __TBB_mutex_padding_H
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#define __TBB_mutex_padding_H
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// wrapper for padding mutexes to be alone on a cache line, without requiring they be allocated
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// from a pool. Because we allow them to be defined anywhere they must be two cache lines in size.
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namespace tbb {
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namespace interface7 {
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namespace internal {
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static const size_t cache_line_size = 64;
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// Pad a mutex to occupy a number of full cache lines sufficient to avoid false sharing
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// with other data; space overhead is up to 2*cache_line_size-1.
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template<typename Mutex, bool is_rw> class padded_mutex;
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template<typename Mutex>
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class padded_mutex<Mutex,false> : tbb::internal::mutex_copy_deprecated_and_disabled {
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typedef long pad_type;
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pad_type my_pad[((sizeof(Mutex)+cache_line_size-1)/cache_line_size+1)*cache_line_size/sizeof(pad_type)];
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Mutex *impl() { return (Mutex *)((uintptr_t(this)|(cache_line_size-1))+1);}
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public:
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static const bool is_rw_mutex = Mutex::is_rw_mutex;
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static const bool is_recursive_mutex = Mutex::is_recursive_mutex;
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static const bool is_fair_mutex = Mutex::is_fair_mutex;
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padded_mutex() { new(impl()) Mutex(); }
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~padded_mutex() { impl()->~Mutex(); }
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//! Represents acquisition of a mutex.
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class scoped_lock : tbb::internal::no_copy {
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typename Mutex::scoped_lock my_scoped_lock;
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public:
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scoped_lock() : my_scoped_lock() {}
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scoped_lock( padded_mutex& m ) : my_scoped_lock(*m.impl()) { }
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~scoped_lock() { }
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void acquire( padded_mutex& m ) { my_scoped_lock.acquire(*m.impl()); }
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bool try_acquire( padded_mutex& m ) { return my_scoped_lock.try_acquire(*m.impl()); }
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void release() { my_scoped_lock.release(); }
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};
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};
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template<typename Mutex>
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class padded_mutex<Mutex,true> : tbb::internal::mutex_copy_deprecated_and_disabled {
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typedef long pad_type;
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pad_type my_pad[((sizeof(Mutex)+cache_line_size-1)/cache_line_size+1)*cache_line_size/sizeof(pad_type)];
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Mutex *impl() { return (Mutex *)((uintptr_t(this)|(cache_line_size-1))+1);}
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public:
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static const bool is_rw_mutex = Mutex::is_rw_mutex;
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static const bool is_recursive_mutex = Mutex::is_recursive_mutex;
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static const bool is_fair_mutex = Mutex::is_fair_mutex;
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padded_mutex() { new(impl()) Mutex(); }
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~padded_mutex() { impl()->~Mutex(); }
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//! Represents acquisition of a mutex.
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class scoped_lock : tbb::internal::no_copy {
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typename Mutex::scoped_lock my_scoped_lock;
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public:
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scoped_lock() : my_scoped_lock() {}
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scoped_lock( padded_mutex& m, bool write = true ) : my_scoped_lock(*m.impl(),write) { }
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~scoped_lock() { }
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void acquire( padded_mutex& m, bool write = true ) { my_scoped_lock.acquire(*m.impl(),write); }
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bool try_acquire( padded_mutex& m, bool write = true ) { return my_scoped_lock.try_acquire(*m.impl(),write); }
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bool upgrade_to_writer() { return my_scoped_lock.upgrade_to_writer(); }
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bool downgrade_to_reader() { return my_scoped_lock.downgrade_to_reader(); }
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void release() { my_scoped_lock.release(); }
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};
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};
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} // namespace internal
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} // namespace interface7
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} // namespace tbb
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#endif /* __TBB_mutex_padding_H */
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