| 1 | // Copyright 2009-2021 Intel Corporation |
|---|---|
| 2 | // SPDX-License-Identifier: Apache-2.0 |
| 3 | |
| 4 | #pragma once |
| 5 | |
| 6 | #include "platform.h" |
| 7 | #include "intrinsics.h" |
| 8 | #include "atomic.h" |
| 9 | |
| 10 | namespace embree |
| 11 | { |
| 12 | /*! system mutex */ |
| 13 | class MutexSys { |
| 14 | friend struct ConditionImplementation; |
| 15 | public: |
| 16 | MutexSys(); |
| 17 | ~MutexSys(); |
| 18 | |
| 19 | private: |
| 20 | MutexSys (const MutexSys& other) DELETED; // do not implement |
| 21 | MutexSys& operator= (const MutexSys& other) DELETED; // do not implement |
| 22 | |
| 23 | public: |
| 24 | void lock(); |
| 25 | bool try_lock(); |
| 26 | void unlock(); |
| 27 | |
| 28 | protected: |
| 29 | void* mutex; |
| 30 | }; |
| 31 | |
| 32 | /*! spinning mutex */ |
| 33 | class SpinLock |
| 34 | { |
| 35 | public: |
| 36 | |
| 37 | SpinLock () |
| 38 | : flag(false) {} |
| 39 | |
| 40 | __forceinline bool isLocked() { |
| 41 | return flag.load(); |
| 42 | } |
| 43 | |
| 44 | __forceinline void lock() |
| 45 | { |
| 46 | while (true) |
| 47 | { |
| 48 | while (flag.load()) |
| 49 | { |
| 50 | _mm_pause(); |
| 51 | _mm_pause(); |
| 52 | } |
| 53 | |
| 54 | bool expected = false; |
| 55 | if (flag.compare_exchange_strong(i1&: expected,i2: true,m: std::memory_order_acquire)) |
| 56 | break; |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | __forceinline bool try_lock() |
| 61 | { |
| 62 | bool expected = false; |
| 63 | if (flag.load() != expected) { |
| 64 | return false; |
| 65 | } |
| 66 | return flag.compare_exchange_strong(i1&: expected,i2: true,m: std::memory_order_acquire); |
| 67 | } |
| 68 | |
| 69 | __forceinline void unlock() { |
| 70 | flag.store(i: false,m: std::memory_order_release); |
| 71 | } |
| 72 | |
| 73 | __forceinline void wait_until_unlocked() |
| 74 | { |
| 75 | while(flag.load()) |
| 76 | { |
| 77 | _mm_pause(); |
| 78 | _mm_pause(); |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | public: |
| 83 | atomic<bool> flag; |
| 84 | }; |
| 85 | |
| 86 | /*! safe mutex lock and unlock helper */ |
| 87 | template<typename Mutex> class Lock { |
| 88 | public: |
| 89 | Lock (Mutex& mutex) : mutex(mutex), locked(true) { mutex.lock(); } |
| 90 | Lock (Mutex& mutex, bool locked) : mutex(mutex), locked(locked) {} |
| 91 | ~Lock() { if (locked) mutex.unlock(); } |
| 92 | __forceinline void lock() { assert(!locked); locked = true; mutex.lock(); } |
| 93 | __forceinline bool isLocked() const { return locked; } |
| 94 | protected: |
| 95 | Mutex& mutex; |
| 96 | bool locked; |
| 97 | }; |
| 98 | } |
| 99 |