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using ManagedArray::reallocate() on a default-constructed ManagedArray doesn't actually allocate at all #90

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using ManagedArray::reallocate() on a default-constructed ManagedArray doesn't actually allocate at all #90

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18 changes: 12 additions & 6 deletions src/chai/ArrayManager.inl
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Original file line number Diff line number Diff line change
Expand Up @@ -47,20 +47,26 @@ void* ArrayManager::reallocate(void* pointer, size_t elems, PointerRecord* point
for (int space = CPU; space < NUM_EXECUTION_SPACES; ++space) {
void* old_ptr = pointer_record->m_pointers[space];

if (old_ptr) {
pointer_record->m_user_callback(ACTION_ALLOC, ExecutionSpace(space), sizeof(T) * elems);
void* new_ptr = m_allocators[space]->allocate(sizeof(T)*elems);
pointer_record->m_user_callback(ACTION_ALLOC, ExecutionSpace(space), sizeof(T) * elems);
void* new_ptr = m_allocators[space]->allocate(sizeof(T)*elems);
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@robinson96 robinson96 Oct 30, 2019 •
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looks good, wait for David or Adam to approve as well.

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This will cause reallocate to allocate a pointer in every space - I'm not sure that's what we want.

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@wrtobin @robinson96 - I think this PR introduces an unexpected change in behavior, can you take a look?

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ooh - you're right David.
Bill, the model should preserve lazy allocation of device memory so that reallocations don't inadvertently initialize device memory if they haven't used gpu memory before. At one point, we had an implementation of reallocate that also strode to only do a deep copy of the data on any memory space where the data was active.


if (old_ptr) {
m_resource_manager.copy(new_ptr, old_ptr, num_bytes_to_copy);
}

pointer_record->m_user_callback(ACTION_FREE, ExecutionSpace(space), sizeof(T) * elems);

pointer_record->m_user_callback(ACTION_FREE, ExecutionSpace(space), sizeof(T) * elems);
if (old_ptr) {
m_allocators[space]->deallocate(old_ptr);
}

pointer_record->m_pointers[space] = new_ptr;
pointer_record->m_pointers[space] = new_ptr;

if (old_ptr) {
m_pointer_map.erase(old_ptr);
m_pointer_map.insert(new_ptr, pointer_record);
}

m_pointer_map.insert(new_ptr, pointer_record);
}

pointer_record->m_size = sizeof(T) * elems;
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3 changes: 2 additions & 1 deletion src/chai/ManagedArray.inl
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Expand Up @@ -31,8 +31,9 @@ CHAI_HOST_DEVICE ManagedArray<T>::ManagedArray():
m_pointer_record->m_user_callback = [](Action, ExecutionSpace, size_t) {};

for (int space = CPU; space < NUM_EXECUTION_SPACES; space++) {
m_pointer_record->m_allocators[space] =
m_pointer_record->m_allocators[space] =
m_resource_manager->getAllocatorId(ExecutionSpace(space));
m_pointer_record->m_owned[space] = true;
}
#endif
}
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19 changes: 19 additions & 0 deletions tests/unit/managed_array_unit_tests.cpp
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Expand Up @@ -35,6 +35,25 @@ TEST(ManagedArray, SpaceConstructorCPU)
array.free();
}

TEST(ManagedArray, ReallocDefaultConstructor)
{
chai::ManagedArray<float> array;
array.reallocate(1);
float val = array[0];
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This causes a segfault in the current implementation, as the ManagedArray doesn't actually allocate anything during the reallocate call.

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changes look reasonable to me.

(void)val;
ASSERT_EQ(array.size(), 1u);
}

TEST(ManagedArray, ReallocSizeConstructor)
{
chai::ManagedArray<float> array(10);
array[0] = 1.0;
array[9] = 2.0;
array.reallocate(20);
ASSERT_EQ(array[0], 1.0);
ASSERT_EQ(array[9], 2.0);
}

#if defined(CHAI_ENABLE_CUDA) || defined(CHAI_ENABLE_HIP)
TEST(ManagedArray, SpaceConstructorGPU)
{
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