From 9ec5f75f43c2ecbfdf52b45f78029b1fd1080658 Mon Sep 17 00:00:00 2001
From: bunnei <bunneidev@gmail.com>
Date: Mon, 5 Sep 2022 17:53:44 -0700
Subject: core: hle: kernel: Add KDynamicSlabHeap.

---
 src/core/CMakeLists.txt                   |   1 +
 src/core/hle/kernel/k_dynamic_slab_heap.h | 122 ++++++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 src/core/hle/kernel/k_dynamic_slab_heap.h

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 2bb4dea6a..296571762 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -191,6 +191,7 @@ add_library(core STATIC
     hle/kernel/k_condition_variable.cpp
     hle/kernel/k_condition_variable.h
     hle/kernel/k_dynamic_page_manager.h
+    hle/kernel/k_dynamic_slab_heap.h
     hle/kernel/k_event.cpp
     hle/kernel/k_event.h
     hle/kernel/k_handle_table.cpp
diff --git a/src/core/hle/kernel/k_dynamic_slab_heap.h b/src/core/hle/kernel/k_dynamic_slab_heap.h
new file mode 100644
index 000000000..3a0ddd050
--- /dev/null
+++ b/src/core/hle/kernel/k_dynamic_slab_heap.h
@@ -0,0 +1,122 @@
+// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <atomic>
+
+#include "common/common_funcs.h"
+#include "core/hle/kernel/k_dynamic_page_manager.h"
+#include "core/hle/kernel/k_slab_heap.h"
+
+namespace Kernel {
+
+template <typename T, bool ClearNode = false>
+class KDynamicSlabHeap : protected impl::KSlabHeapImpl {
+    YUZU_NON_COPYABLE(KDynamicSlabHeap);
+    YUZU_NON_MOVEABLE(KDynamicSlabHeap);
+
+public:
+    constexpr KDynamicSlabHeap() = default;
+
+    constexpr VAddr GetAddress() const {
+        return m_address;
+    }
+    constexpr size_t GetSize() const {
+        return m_size;
+    }
+    constexpr size_t GetUsed() const {
+        return m_used.load();
+    }
+    constexpr size_t GetPeak() const {
+        return m_peak.load();
+    }
+    constexpr size_t GetCount() const {
+        return m_count.load();
+    }
+
+    constexpr bool IsInRange(VAddr addr) const {
+        return this->GetAddress() <= addr && addr <= this->GetAddress() + this->GetSize() - 1;
+    }
+
+    void Initialize(KDynamicPageManager* page_allocator, size_t num_objects) {
+        ASSERT(page_allocator != nullptr);
+
+        // Initialize members.
+        m_address = page_allocator->GetAddress();
+        m_size = page_allocator->GetSize();
+
+        // Initialize the base allocator.
+        KSlabHeapImpl::Initialize();
+
+        // Allocate until we have the correct number of objects.
+        while (m_count.load() < num_objects) {
+            auto* allocated = reinterpret_cast<T*>(page_allocator->Allocate());
+            ASSERT(allocated != nullptr);
+
+            for (size_t i = 0; i < sizeof(PageBuffer) / sizeof(T); i++) {
+                KSlabHeapImpl::Free(allocated + i);
+            }
+
+            m_count += sizeof(PageBuffer) / sizeof(T);
+        }
+    }
+
+    T* Allocate(KDynamicPageManager* page_allocator) {
+        T* allocated = static_cast<T*>(KSlabHeapImpl::Allocate());
+
+        // If we successfully allocated and we should clear the node, do so.
+        if constexpr (ClearNode) {
+            if (allocated != nullptr) [[likely]] {
+                reinterpret_cast<KSlabHeapImpl::Node*>(allocated)->next = nullptr;
+            }
+        }
+
+        // If we fail to allocate, try to get a new page from our next allocator.
+        if (allocated == nullptr) [[unlikely]] {
+            if (page_allocator != nullptr) {
+                allocated = reinterpret_cast<T*>(page_allocator->Allocate());
+                if (allocated != nullptr) {
+                    // If we succeeded in getting a page, free the rest to our slab.
+                    for (size_t i = 1; i < sizeof(PageBuffer) / sizeof(T); i++) {
+                        KSlabHeapImpl::Free(allocated + i);
+                    }
+                    m_count += sizeof(PageBuffer) / sizeof(T);
+                }
+            }
+        }
+
+        if (allocated != nullptr) [[likely]] {
+            // Construct the object.
+            std::construct_at(allocated);
+
+            // Update our tracking.
+            const size_t used = ++m_used;
+            size_t peak = m_peak.load();
+            while (peak < used) {
+                if (m_peak.compare_exchange_weak(peak, used, std::memory_order_relaxed)) {
+                    break;
+                }
+            }
+        }
+
+        return allocated;
+    }
+
+    void Free(T* t) {
+        KSlabHeapImpl::Free(t);
+        --m_used;
+    }
+
+private:
+    using PageBuffer = KDynamicPageManager::PageBuffer;
+
+private:
+    std::atomic<size_t> m_used{};
+    std::atomic<size_t> m_peak{};
+    std::atomic<size_t> m_count{};
+    VAddr m_address{};
+    size_t m_size{};
+};
+
+} // namespace Kernel
-- 
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