/*************************************************************************/ /* paged_allocator.h */ /*************************************************************************/ /* This file is part of: */ /* GODOT ENGINE */ /* https://godotengine.org */ /*************************************************************************/ /* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */ /* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */ /* */ /* Permission is hereby granted, free of charge, to any person obtaining */ /* a copy of this software and associated documentation files (the */ /* "Software"), to deal in the Software without restriction, including */ /* without limitation the rights to use, copy, modify, merge, publish, */ /* distribute, sublicense, and/or sell copies of the Software, and to */ /* permit persons to whom the Software is furnished to do so, subject to */ /* the following conditions: */ /* */ /* The above copyright notice and this permission notice shall be */ /* included in all copies or substantial portions of the Software. */ /* */ /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/ /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /*************************************************************************/ #ifndef PAGED_ALLOCATOR_H #define PAGED_ALLOCATOR_H #include "core/os/memory.h" #include "core/os/spin_lock.h" #include "core/typedefs.h" #include <type_traits> template <class T, bool thread_safe = false> class PagedAllocator { T **page_pool = nullptr; T ***available_pool = nullptr; uint32_t pages_allocated = 0; uint32_t allocs_available = 0; uint32_t page_shift = 0; uint32_t page_mask = 0; uint32_t page_size = 0; SpinLock spin_lock; public: template <class... Args> T *alloc(const Args &&...p_args) { if (thread_safe) { spin_lock.lock(); } if (unlikely(allocs_available == 0)) { uint32_t pages_used = pages_allocated; pages_allocated++; page_pool = (T **)memrealloc(page_pool, sizeof(T *) * pages_allocated); available_pool = (T ***)memrealloc(available_pool, sizeof(T **) * pages_allocated); page_pool[pages_used] = (T *)memalloc(sizeof(T) * page_size); available_pool[pages_used] = (T **)memalloc(sizeof(T *) * page_size); for (uint32_t i = 0; i < page_size; i++) { available_pool[0][i] = &page_pool[pages_used][i]; } allocs_available += page_size; } allocs_available--; T *alloc = available_pool[allocs_available >> page_shift][allocs_available & page_mask]; if (thread_safe) { spin_lock.unlock(); } memnew_placement(alloc, T(p_args...)); return alloc; } void free(T *p_mem) { if (thread_safe) { spin_lock.lock(); } p_mem->~T(); available_pool[allocs_available >> page_shift][allocs_available & page_mask] = p_mem; if (thread_safe) { spin_lock.unlock(); } allocs_available++; } void reset(bool p_allow_unfreed = false) { if (!p_allow_unfreed || !std::is_trivially_destructible<T>::value) { ERR_FAIL_COND(allocs_available < pages_allocated * page_size); } if (pages_allocated) { for (uint32_t i = 0; i < pages_allocated; i++) { memfree(page_pool[i]); memfree(available_pool[i]); } memfree(page_pool); memfree(available_pool); page_pool = nullptr; available_pool = nullptr; pages_allocated = 0; allocs_available = 0; } } bool is_configured() const { return page_size > 0; } void configure(uint32_t p_page_size) { ERR_FAIL_COND(page_pool != nullptr); //sanity check ERR_FAIL_COND(p_page_size == 0); page_size = nearest_power_of_2_templated(p_page_size); page_mask = page_size - 1; page_shift = get_shift_from_power_of_2(page_size); } PagedAllocator(uint32_t p_page_size = 4096) { // power of 2 recommended because of alignment with OS page sizes. Even if element is bigger, its still a multiple and get rounded amount of pages configure(p_page_size); } ~PagedAllocator() { ERR_FAIL_COND_MSG(allocs_available < pages_allocated * page_size, "Pages in use exist at exit in PagedAllocator"); reset(); } }; #endif // PAGED_ALLOCATOR_H