jdk-24/test/hotspot/gtest/memory/test_arena.cpp

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 * Copyright (c) 2021 SAP SE. All rights reserved.
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 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#include "precompiled.hpp"
#include "memory/arena.hpp"
#include "runtime/os.hpp"
#include "utilities/align.hpp"
#include "utilities/globalDefinitions.hpp"
#include "unittest.hpp"
#include "testutils.hpp"

#define ASSERT_CONTAINS(ar, p) ASSERT_TRUE(ar.contains(p))

// Note:
// - Amalloc returns 64bit aligned pointer (also on 32-bit)
// - AmallocWords returns word-aligned pointer
#define ASSERT_ALIGN_AMALLOC(p)       ASSERT_ALIGN(p, ARENA_AMALLOC_ALIGNMENT)
#define ASSERT_ALIGN_AMALLOCWORDS(p)  ASSERT_ALIGN(p, BytesPerWords)

// Do a couple of checks on the return of a successful Amalloc
#define ASSERT_AMALLOC(ar, p) \
  ASSERT_NOT_NULL(p); \
  ASSERT_CONTAINS(ar, p); \
  ASSERT_ALIGN_AMALLOC(p);

// #define LOG(s) tty->print_cr s;
#define LOG(s)

// Test behavior for Amalloc(0).
// Amalloc just ignores Amalloc(0) and returns the current hwm without increasing it.
// Therefore, the returned pointer should be not null, aligned, but not (!) contained
// in the arena since hwm points beyond the arena.
TEST_VM(Arena, alloc_size_0) {
  Arena ar(mtTest);
  void* p = ar.Amalloc(0);
  ASSERT_NOT_NULL(p);
  ASSERT_ALIGN_AMALLOC(p);

  ASSERT_FALSE(ar.contains(p));
  // Allocate again. The new allocations should have the same position as the 0-sized
  // first one.
  void* p2 = ar.Amalloc(1);
  ASSERT_AMALLOC(ar, p2);
  ASSERT_EQ(p2, p);
}

// Test behavior for Arealloc(p, 0)
TEST_VM(Arena, realloc_size_0) {
  // Arealloc(p, 0) behaves like Afree(p). It should release the memory
  // and, if top position, roll back the hwm.
  Arena ar(mtTest);
  void* p1 = ar.Amalloc(0x10);
  ASSERT_AMALLOC(ar, p1);
  void* p2 = ar.Arealloc(p1, 0x10, 0);
  ASSERT_NULL(p2);

  // a subsequent allocation should get the same pointer
  void* p3 = ar.Amalloc(0x20);
  ASSERT_EQ(p3, p1);
}

// Realloc equal sizes is a noop
TEST_VM(Arena, realloc_same_size) {
  Arena ar(mtTest);
  void* p1 = ar.Amalloc(0x200);
  ASSERT_AMALLOC(ar, p1);
  GtestUtils::mark_range(p1, 0x200);

  void* p2 = ar.Arealloc(p1, 0x200, 0x200);

  ASSERT_EQ(p2, p1);
  ASSERT_RANGE_IS_MARKED(p2, 0x200);
}

// Test behavior for Afree(nullptr) and Arealloc(nullptr, x)
TEST_VM(Arena, free_null) {
  Arena ar(mtTest);
  ar.Afree(nullptr, 10); // should just be ignored
}

TEST_VM(Arena, realloc_null) {
  Arena ar(mtTest);
  void* p = ar.Arealloc(nullptr, 0, 20); // equivalent to Amalloc(20)
  ASSERT_AMALLOC(ar, p);
}

// Check Arena.Afree in a non-top position.
// The free'd allocation should be zapped (debug only),
// surrounding blocks should be unaffected.
TEST_VM(Arena, free_nontop) {
  Arena ar(mtTest);

  void* p_before = ar.Amalloc(0x10);
  ASSERT_AMALLOC(ar, p_before);
  GtestUtils::mark_range(p_before, 0x10);

  void* p = ar.Amalloc(0x10);
  ASSERT_AMALLOC(ar, p);
  GtestUtils::mark_range_with(p, 0x10, 'Z');

  void* p_after = ar.Amalloc(0x10);
  ASSERT_AMALLOC(ar, p_after);
  GtestUtils::mark_range(p_after, 0x10);

  ASSERT_RANGE_IS_MARKED(p_before, 0x10);
  ASSERT_RANGE_IS_MARKED_WITH(p, 0x10, 'Z');
  ASSERT_RANGE_IS_MARKED(p_after, 0x10);

  ar.Afree(p, 0x10);

  ASSERT_RANGE_IS_MARKED(p_before, 0x10);
  DEBUG_ONLY(ASSERT_RANGE_IS_MARKED_WITH(p, 0x10, badResourceValue);)
  ASSERT_RANGE_IS_MARKED(p_after, 0x10);
}

// Check Arena.Afree in a top position.
// The free'd allocation (non-top) should be zapped (debug only),
// the hwm should have been rolled back.
TEST_VM(Arena, free_top) {
  Arena ar(mtTest);

  void* p = ar.Amalloc(0x10);
  ASSERT_AMALLOC(ar, p);
  GtestUtils::mark_range_with(p, 0x10, 'Z');

  ar.Afree(p, 0x10);
  DEBUG_ONLY(ASSERT_RANGE_IS_MARKED_WITH(p, 0x10, badResourceValue);)

  // a subsequent allocation should get the same pointer
  void* p2 = ar.Amalloc(0x20);
  ASSERT_EQ(p2, p);
}


// In-place shrinking.
TEST_VM(Arena, realloc_top_shrink) {
  Arena ar(mtTest);

  void* p1 = ar.Amalloc(0x200);
  ASSERT_AMALLOC(ar, p1);
  GtestUtils::mark_range(p1, 0x200);

  void* p2 = ar.Arealloc(p1, 0x200, 0x100);
  ASSERT_EQ(p1, p2);
  ASSERT_RANGE_IS_MARKED(p2, 0x100); // realloc should preserve old content

  // A subsequent allocation should be placed right after the end of the first, shrunk, allocation
  void* p3 = ar.Amalloc(1);
  ASSERT_EQ(p3, ((char*)p1) + 0x100);
}

// not-in-place shrinking.
TEST_VM(Arena, realloc_nontop_shrink) {
  Arena ar(mtTest);

  void* p1 = ar.Amalloc(200);
  ASSERT_AMALLOC(ar, p1);
  GtestUtils::mark_range(p1, 200);

  void* p_other = ar.Amalloc(20); // new top, p1 not top anymore

  void* p2 = ar.Arealloc(p1, 200, 100);
  ASSERT_EQ(p1, p2); // should still shrink in place
  ASSERT_RANGE_IS_MARKED(p2, 100); // realloc should preserve old content
}

// in-place growing.
TEST_VM(Arena, realloc_top_grow) {
  Arena ar(mtTest); // initial chunk size large enough to ensure below allocation grows in-place.

  void* p1 = ar.Amalloc(0x10);
  ASSERT_AMALLOC(ar, p1);
  GtestUtils::mark_range(p1, 0x10);

  void* p2 = ar.Arealloc(p1, 0x10, 0x20);
  ASSERT_EQ(p1, p2);
  ASSERT_RANGE_IS_MARKED(p2, 0x10); // realloc should preserve old content
}

// not-in-place growing.
TEST_VM(Arena, realloc_nontop_grow) {
  Arena ar(mtTest);

  void* p1 = ar.Amalloc(10);
  ASSERT_AMALLOC(ar, p1);
  GtestUtils::mark_range(p1, 10);

  void* p_other = ar.Amalloc(20); // new top, p1 not top anymore

  void* p2 = ar.Arealloc(p1, 10, 20);
  ASSERT_AMALLOC(ar, p2);
  ASSERT_RANGE_IS_MARKED(p2, 10); // realloc should preserve old content
}

// -------- random alloc test -------------

static uint8_t canary(int i) {
  return (uint8_t)('A' + i % 26);
}

// Randomly allocate and reallocate with random sizes and differing alignments;
//  check alignment; check for overwriters.
// We do this a number of times, to give chunk pool handling a good workout too.
TEST_VM(Arena, random_allocs) {

  const int num_allocs = 250 * 1000;
  const int avg_alloc_size = 64;

  void** ptrs = NEW_C_HEAP_ARRAY(void*, num_allocs, mtTest);
  size_t* sizes = NEW_C_HEAP_ARRAY(size_t, num_allocs, mtTest);
  size_t* alignments = NEW_C_HEAP_ARRAY(size_t, num_allocs, mtTest);

  Arena ar(mtTest);

  // Allocate
  for (int i = 0; i < num_allocs; i ++) {
    size_t size = os::random() % (avg_alloc_size * 2); // Note: size==0 is okay; we want to test that too
    size_t alignment = 0;
    void* p = nullptr;
    if (os::random() % 2) { // randomly switch between Amalloc and AmallocWords
      p = ar.Amalloc(size);
      alignment = BytesPerLong;
    } else {
      // Inconsistency: AmallocWords wants its input size word aligned, whereas Amalloc takes
      //  care of alignment itself. We may want to clean this up, but for now just go with it.
      size = align_up(size, BytesPerWord);
      p = ar.AmallocWords(size);
      alignment = BytesPerWord;
    }
    LOG(("[%d]: " PTR_FORMAT ", size " SIZE_FORMAT ", aligned " SIZE_FORMAT,
         i, p2i(p), size, alignment));
    ASSERT_NOT_NULL(p);
    ASSERT_ALIGN(p, alignment);
    if (size > 0) {
      ASSERT_CONTAINS(ar, p);
    }
    GtestUtils::mark_range_with(p, size, canary(i));
    ptrs[i] = p; sizes[i] = size; alignments[i] = alignment;
  }

  // Check pattern in allocations for overwriters.
  for (int i = 0; i < num_allocs; i ++) {
    ASSERT_RANGE_IS_MARKED_WITH(ptrs[i], sizes[i], canary(i));
  }

  // realloc all of them
  for (int i = 0; i < num_allocs; i ++) {
    size_t new_size = os::random() % (avg_alloc_size * 2);  // Note: 0 is possible and should work
    void* p2 = ar.Arealloc(ptrs[i], sizes[i], new_size);
    if (new_size > 0) {
      ASSERT_NOT_NULL(p2);
      ASSERT_CONTAINS(ar, p2);
      ASSERT_ALIGN(p2, alignments[i]); // Realloc guarantees at least the original alignment
      ASSERT_RANGE_IS_MARKED_WITH(p2, MIN2(sizes[i], new_size), canary(i)); // old content should have been preserved

      GtestUtils::mark_range_with(p2, new_size, canary(i)); // mark new range with canary
    } else {
      ASSERT_NULL(p2);
    }
    ptrs[i] = p2; sizes[i] = new_size;
    LOG(("[%d]: realloc " PTR_FORMAT ", size " SIZE_FORMAT ", aligned " SIZE_FORMAT,
         i, p2i(p2), new_size, alignments[i]));
  }

  // Check test pattern again
  //  Note that we don't check the gap pattern anymore since if allocations had been shrunk in place
  //  this now gets difficult.
  for (int i = 0; i < num_allocs; i ++) {
    ASSERT_RANGE_IS_MARKED_WITH(ptrs[i], sizes[i], canary(i));
  }

  // Randomly free a bunch of allocations.
  for (int i = 0; i < num_allocs; i ++) {
    if (os::random() % 10 == 0) {
      ar.Afree(ptrs[i], sizes[i]);
      // In debug builds the freed space should be filled the space with badResourceValue
      DEBUG_ONLY(ASSERT_RANGE_IS_MARKED_WITH(ptrs[i], sizes[i], badResourceValue));
      ptrs[i] = nullptr;
    }
  }

  // Check test pattern again
  for (int i = 0; i < num_allocs; i ++) {
    ASSERT_RANGE_IS_MARKED_WITH(ptrs[i], sizes[i], canary(i));
  }

  // Free temp data
  FREE_C_HEAP_ARRAY(char*, ptrs);
  FREE_C_HEAP_ARRAY(size_t, sizes);
  FREE_C_HEAP_ARRAY(size_t, alignments);
}

#ifndef LP64
// These tests below are about alignment issues when mixing Amalloc and AmallocWords.
// Since on 64-bit these APIs offer the same alignment, they only matter for 32-bit.

TEST_VM(Arena, mixed_alignment_allocation) {
  // Test that mixed alignment allocations work and provide allocations with the correct
  // alignment
  Arena ar(mtTest);
  void* p1 = ar.AmallocWords(BytesPerWord);
  void* p2 = ar.Amalloc(BytesPerLong);
  ASSERT_TRUE(is_aligned(p1, BytesPerWord));
  ASSERT_TRUE(is_aligned(p2, ARENA_AMALLOC_ALIGNMENT));
}

TEST_VM(Arena, Arena_with_crooked_initial_size) {
  // Test that an arena with a crooked, not 64-bit aligned initial size
  // works
  Arena ar(mtTest, Arena::Tag::tag_other, 4097);
  void* p1 = ar.AmallocWords(BytesPerWord);
  void* p2 = ar.Amalloc(BytesPerLong);
  ASSERT_TRUE(is_aligned(p1, BytesPerWord));
  ASSERT_TRUE(is_aligned(p2, ARENA_AMALLOC_ALIGNMENT));
}

TEST_VM(Arena, Arena_grows_large_unaligned) {
  // Test that if the arena grows with a large unaligned value, nothing bad happens.
  // We trigger allocation of a new, large, unaligned chunk with a non-standard size
  // (only possible on 32-bit when allocating with word alignment).
  // Then we alloc some more. If Arena::grow() does not correctly align, on 32-bit
  // something should assert at some point.
  Arena ar(mtTest, Arena::Tag::tag_other, 100); // first chunk is small
  void* p = ar.AmallocWords(Chunk::size + BytesPerWord); // if Arena::grow() misaligns, this asserts
  // some more allocations for good measure
  for (int i = 0; i < 100; i ++) {
    ar.Amalloc(1);
  }
}

#endif //  LP64

static size_t random_arena_chunk_size() {
  // Return with a 50% rate a standard size, otherwise some random size
  if (os::random() % 10 < 5) {
    static const size_t standard_sizes[4] = {
        Chunk::tiny_size, Chunk::init_size, Chunk::size, Chunk::medium_size
    };
    return standard_sizes[os::random() % 4];
  }
  return ARENA_ALIGN(os::random() % 1024);
}

TEST_VM(Arena, different_chunk_sizes) {
  // Test the creation/pooling of chunks; since ChunkPool is hidden, the
  //  only way to test this is to create/destroy arenas with different init sizes,
  //  which determines the initial chunk size.
  // Note that since the chunk pools are global and get cleaned out periodically,
  //  there is no safe way to actually test their occupancy here.
  for (int i = 0; i < 1000; i ++) {
    // Unfortunately, Arenas cannot be newed,
    // so we are left with awkwardly placing a few on the stack.
    Arena ar0(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
    Arena ar1(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
    Arena ar2(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
    Arena ar3(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
    Arena ar4(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
    Arena ar5(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
    Arena ar6(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
    Arena ar7(mtTest, Arena::Tag::tag_other, random_arena_chunk_size());
  }
}