/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <folly/experimental/JemallocHugePageAllocator.h>

#include <folly/container/F14Map.h>

#include <folly/memory/Malloc.h>
#include <folly/portability/GTest.h>

#include <vector>

using jha = folly::JemallocHugePageAllocator;

static constexpr int kb(int kilos) {
  return kilos * 1024;
}

static constexpr int mb(int megs) {
  return kb(megs * 1024);
}

TEST(JemallocHugePageAllocatorTest, Basic) {
  EXPECT_FALSE(jha::initialized());

  // Allocation should work even if uninitialized
  auto ptr = jha::allocate(kb(1));
  EXPECT_NE(nullptr, ptr);
  jha::deallocate(ptr);

  bool initialized = jha::init(1);
  if (initialized) {
    EXPECT_NE(0, jha::freeSpace());
  }

  ptr = jha::allocate(kb(1));
  EXPECT_NE(nullptr, ptr);

  if (initialized) {
    EXPECT_TRUE(jha::addressInArena(ptr));
  }

  // Allocate some arrays on huge page
  auto array_of_arrays = new (ptr) std::array<int, 100>[5];

  if (initialized) {
    EXPECT_FALSE(jha::addressInArena(&array_of_arrays));
    EXPECT_TRUE(jha::addressInArena(&array_of_arrays[0]));
    EXPECT_TRUE(jha::addressInArena(&array_of_arrays[0][0]));
  }

  jha::deallocate(ptr);
}

TEST(JemallocHugePageAllocatorTest, LargeAllocations) {
  // Allocate before init - will not use huge pages
  void* ptr0 = jha::allocate(kb(1));

  // One 2MB huge page
  bool initialized = jha::init(1);
  if (initialized) {
    EXPECT_NE(0, jha::freeSpace());
  }

  // This fits
  void* ptr1 = jha::allocate(mb(2));
  EXPECT_NE(nullptr, ptr1);

  if (initialized) {
    EXPECT_TRUE(jha::addressInArena(ptr1));
  }

  // This is too large to fit
  void* ptr2 = jha::allocate(mb(1));
  EXPECT_NE(nullptr, ptr2);

  EXPECT_FALSE(jha::addressInArena(ptr2));

  // Free and reuse huge page area
  jha::deallocate(ptr2);
  jha::deallocate(ptr0);
  ptr2 = jha::allocate(kb(64));

  // No memory in the huge page arena was freed - ptr0 was allocated
  // before init and ptr2 didn't fit
  EXPECT_FALSE(jha::addressInArena(ptr2));

  jha::deallocate(ptr1);
  void* ptr3 = jha::allocate(mb(1) + kb(512));
  EXPECT_NE(nullptr, ptr3);

  if (initialized) {
    EXPECT_EQ(ptr1, ptr3);
    EXPECT_TRUE(jha::addressInArena(ptr3));
  }

  // Just using free works equally well
  free(ptr3);
  ptr3 = jha::allocate(mb(1) + kb(512));
  EXPECT_NE(nullptr, ptr3);

  if (initialized) {
    EXPECT_TRUE(jha::addressInArena(ptr3));
  }

  jha::deallocate(ptr2);
  jha::deallocate(ptr3);
}

TEST(JemallocHugePageAllocatorTest, MemoryUsageTest) {
  bool initialized = jha::init(80);
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(160));
  }

  struct c32 {
    char val[32];
  };
  using Vec32 = std::vector<c32, folly::CxxHugePageAllocator<c32>>;
  Vec32 vec32;
  for (int i = 0; i < 10; i++) {
    vec32.push_back({});
  }
  void* ptr1 = jha::allocate(32);
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(158));
  }
  struct c320 {
    char val[320];
  };
  using Vec320 = std::vector<c320, folly::CxxHugePageAllocator<c320>>;
  Vec320 vec320;
  for (int i = 0; i < 10; i++) {
    vec320.push_back({});
  }
  void* ptr2 = jha::allocate(320);
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(158));
  }

  // Helper to ensure all allocations are freed at the end
  auto deleter = [](void* data) { jha::deallocate(data); };
  std::vector<std::unique_ptr<void, decltype(deleter)>> ptr_vec;
  auto alloc = [&ptr_vec, &deleter](size_t size) {
    ptr_vec.emplace_back(jha::allocate(size), deleter);
  };

  for (int i = 0; i < 10; i++) {
    alloc(kb(1));
  }
  void* ptr3 = jha::allocate(kb(1));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(158));
  }
  for (int i = 0; i < 10; i++) {
    alloc(kb(4));
  }
  void* ptr4 = jha::allocate(kb(4));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(158));
  }
  for (int i = 0; i < 10; i++) {
    alloc(kb(10));
  }
  void* ptr5 = jha::allocate(kb(10));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(158));
  }
  alloc(kb(512));
  alloc(mb(1));
  void* ptr6 = jha::allocate(mb(1));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(156));
  }
  alloc(mb(2));
  alloc(mb(4));
  void* ptr7 = jha::allocate(mb(4));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(146));
  }
  alloc(kb(512));
  alloc(kb(512));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), 145);
  }
  void* ptr8 = jha::allocate(mb(64));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(80));
  }
  alloc(mb(64));
  if (initialized) {
    EXPECT_GE(jha::freeSpace(), mb(16));
  }
  alloc(mb(256));
  alloc(mb(256));
  alloc(mb(256));

  // Now free a bunch of objects and then reallocate
  // the same size objects again.
  // This should not result in usage of free space.
  size_t free = jha::freeSpace();
  jha::deallocate(ptr1);
  jha::deallocate(ptr2);
  jha::deallocate(ptr3);
  jha::deallocate(ptr4);
  jha::deallocate(ptr5);
  jha::deallocate(ptr6);
  jha::deallocate(ptr7);
  jha::deallocate(ptr8);
  alloc(32);
  alloc(320);
  alloc(kb(1));
  alloc(kb(4));
  alloc(kb(10));
  alloc(mb(1));
  alloc(mb(4));
  alloc(mb(64));

  if (initialized) {
    EXPECT_EQ(free, jha::freeSpace());
  }
}

TEST(JemallocHugePageAllocatorTest, STLAllocator) {
  using MyVecAllocator = folly::CxxHugePageAllocator<int>;
  using MyVec = std::vector<int, MyVecAllocator>;

  using MyMapAllocator =
      folly::CxxHugePageAllocator<folly::f14::detail::MapValueType<int, MyVec>>;
  using MyMap = folly::F14FastMap<
      int,
      MyVec,
      folly::f14::DefaultHasher<int>,
      folly::f14::DefaultKeyEqual<int>,
      MyMapAllocator>;

  MyVec vec;
  // This should work, just won't get huge pages since
  // init hasn't been called yet
  vec.resize(100);
  EXPECT_NE(nullptr, vec.data());

  // Reserve & initialize, not on huge pages
  MyVec vec2(100);
  EXPECT_NE(nullptr, vec.data());

  // F14 maps need quite a lot of memory by default
  bool initialized = jha::init(4);
  if (initialized) {
    EXPECT_NE(0, jha::freeSpace());
  }

  // Reallocate, this time on huge pages
  vec.resize(200);
  EXPECT_NE(nullptr, vec.data());

  MyMap map1;
  map1[0] = {1, 2, 3};
  auto map2_ptr = std::make_unique<MyMap>();
  MyMap& map2 = *map2_ptr;
  map2[0] = {1, 2, 3};

  if (initialized) {
    EXPECT_TRUE(jha::addressInArena(vec.data()));
    EXPECT_TRUE(jha::addressInArena(&map1[0]));
    EXPECT_TRUE(jha::addressInArena(&map1[0][0]));
    EXPECT_TRUE(jha::addressInArena(&map2[0]));
    EXPECT_TRUE(jha::addressInArena(&map2[0][0]));
  }

  // This will be on the huge page arena
  map1[0] = std::move(vec);

  // But not this, since vec2 content was allocated before init
  map1[1] = std::move(vec2);

  if (initialized) {
    EXPECT_TRUE(jha::addressInArena(&map1[0]));
    EXPECT_TRUE(jha::addressInArena(&map1[1]));
    EXPECT_TRUE(jha::addressInArena(&map1[0][0]));
    EXPECT_FALSE(jha::addressInArena(&map1[1][0]));
  }

  // realloc on huge pages
  map1[1].reserve(200);

  if (initialized) {
    EXPECT_TRUE(jha::addressInArena(&map1[1][0]));
  }
}

TEST(JemallocHugePageAllocatorTest, Grow) {
  bool initialized = jha::init(2, 8192);
  if (initialized) {
    EXPECT_NE(0, jha::freeSpace());
  }

  // This fits
  void* ptr1 = jha::allocate(mb(1));
  EXPECT_NE(nullptr, ptr1);

  // This partially fits
  void* ptr2 = jha::allocate(mb(6));
  EXPECT_NE(nullptr, ptr2);

  void* ptr3 = jha::allocate(mb(500));
  EXPECT_NE(nullptr, ptr3);

  void* ptr4 = jha::allocate(kb(4));
  EXPECT_NE(nullptr, ptr4);

  void* ptr5 = jha::allocate(kb(4));
  EXPECT_NE(nullptr, ptr5);

  if (initialized) {
    EXPECT_TRUE(jha::addressInArena(ptr1));
    EXPECT_TRUE(jha::addressInArena(ptr2));
    EXPECT_TRUE(jha::addressInArena(ptr3));
    EXPECT_TRUE(jha::addressInArena(ptr4));
    EXPECT_TRUE(jha::addressInArena(ptr5));
  }

  jha::deallocate(ptr1);
  jha::deallocate(ptr2);
  jha::deallocate(ptr3);
  jha::deallocate(ptr4);
  jha::deallocate(ptr5);
}
