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Apr 29, 2025
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Improve coarse_alloc() #1249

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156 changes: 97 additions & 59 deletions src/coarse/coarse.c
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Original file line number Diff line number Diff line change
Expand Up @@ -623,6 +623,24 @@ static umf_result_t coarse_add_used_block(coarse_t *coarse, void *addr,
return UMF_RESULT_SUCCESS;
}

static umf_result_t coarse_add_free_block(coarse_t *coarse, void *addr,
size_t size, block_t **free_block) {
*free_block = NULL;

block_t *new_block =
coarse_ravl_add_new(coarse->all_blocks, addr, size, NULL);
if (new_block == NULL) {
return UMF_RESULT_ERROR_OUT_OF_HOST_MEMORY;
}

new_block->used = false;
coarse->alloc_size += size;

*free_block = new_block;

return UMF_RESULT_SUCCESS;
}

static void coarse_ravl_cb_rm_all_blocks_node(void *data, void *arg) {
assert(data);
assert(arg);
Expand Down Expand Up @@ -1053,88 +1071,108 @@ umf_result_t coarse_alloc(coarse_t *coarse, size_t size, size_t alignment,

assert(debug_check(coarse));

*resultPtr = NULL;

// Find a block with greater or equal size using the given memory allocation strategy
block_t *curr = find_free_block(coarse->free_blocks, size, alignment,
coarse->allocation_strategy);

// If the block that we want to reuse has a greater size, split it.
// Try to merge the split part with the successor if it is not used.
enum { ACTION_NONE = 0, ACTION_USE, ACTION_SPLIT } action = ACTION_NONE;

if (curr && curr->size > size) {
action = ACTION_SPLIT;
} else if (curr && curr->size == size) {
action = ACTION_USE;
}

if (action) { // ACTION_SPLIT or ACTION_USE
assert(curr->used == false);

// In case of non-zero alignment create an aligned block what would be further used.
if (alignment > 0) {
umf_result = create_aligned_block(coarse, size, alignment, &curr);
if (umf_result != UMF_RESULT_SUCCESS) {
(void)free_blocks_re_add(coarse, curr);
goto err_unlock;
}
if (curr == NULL) {
// no suitable block found - try to get more memory from the upstream provider
umf_result = UMF_RESULT_ERROR_OUT_OF_HOST_MEMORY;

if (!coarse->cb.alloc) {
LOG_ERR("out of memory (the memory provider does not support "
"allocating more memory)");
goto err_unlock;
}

if (action == ACTION_SPLIT) {
// Split the current block and put the new block after the one that we use.
umf_result = split_current_block(coarse, curr, size);
if (umf_result != UMF_RESULT_SUCCESS) {
(void)free_blocks_re_add(coarse, curr);
goto err_unlock;
}
size_t size_aligned = ALIGN_UP_SAFE(size, alignment);
if (size_aligned == 0) {
// cannot align up (arithmetic overflow)
umf_result = UMF_RESULT_ERROR_INVALID_ARGUMENT;
LOG_ERR("size too huge (arithmetic overflow)");
goto err_unlock;
}

curr->size = size;
umf_result = coarse->cb.alloc(coarse->provider, size_aligned, alignment,
resultPtr);
if (umf_result != UMF_RESULT_SUCCESS) {
LOG_ERR("alloc() of memory provider failed: out of memory");
goto err_unlock;
}

LOG_DEBUG("coarse_ALLOC (split_block) %zu used %zu alloc %zu", size,
coarse->used_size, coarse->alloc_size);
ASSERT_IS_ALIGNED(((uintptr_t)(*resultPtr)), alignment);

} else { // action == ACTION_USE
LOG_DEBUG("coarse_ALLOC (same_block) %zu used %zu alloc %zu", size,
coarse->used_size, coarse->alloc_size);
block_t *new_free_block = NULL;
umf_result = coarse_add_free_block(coarse, *resultPtr, size_aligned,
&new_free_block);
if (umf_result != UMF_RESULT_SUCCESS) {
LOG_ERR("failed to add a newly allocated block from the memory "
"provider");
if (coarse->cb.free) {
coarse->cb.free(coarse->provider, *resultPtr, size_aligned);
} else {
LOG_WARN("the memory provider does not support the free() "
"operation, so the following memory block was leaked: "
"address %p, size %zu",
*resultPtr, size_aligned);
}
goto err_unlock;
}

curr->used = true;
*resultPtr = curr->data;
coarse->used_size += size;

assert(debug_check(coarse));
utils_mutex_unlock(&coarse->lock);
LOG_DEBUG("coarse_ALLOC (memory_provider) %zu used %zu alloc %zu",
size_aligned, coarse->used_size, coarse->alloc_size);

return UMF_RESULT_SUCCESS;
curr = new_free_block;
}

// no suitable block found - try to get more memory from the upstream provider
umf_result = UMF_RESULT_ERROR_OUT_OF_HOST_MEMORY;

*resultPtr = NULL;
// If the block that we want to reuse has a greater size, split it.
// Try to merge the split part with the successor if it is not used.
enum { ACTION_NONE = 0, ACTION_USE, ACTION_SPLIT } action = ACTION_NONE;
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ACTION_NONE
AFAIK, starting enum entry is 0, so there is no need to set it up.

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Right, but IMHO it is more readable as it is now


if (!coarse->cb.alloc) {
if (curr && curr->size > size) {
action = ACTION_SPLIT;
} else if (curr && curr->size == size) {
action = ACTION_USE;
} else {
umf_result = UMF_RESULT_ERROR_OUT_OF_HOST_MEMORY;
LOG_ERR("out of memory");
goto err_unlock;
}

umf_result = coarse->cb.alloc(coarse->provider, size, alignment, resultPtr);
if (umf_result != UMF_RESULT_SUCCESS) {
LOG_ERR("coarse_alloc_cb() failed: out of memory");
goto err_unlock;
}
// ACTION_SPLIT or ACTION_USE
assert(curr->used == false);

ASSERT_IS_ALIGNED(((uintptr_t)(*resultPtr)), alignment);
// In case of non-zero alignment create an aligned block what would be further used.
if (alignment > 0) {
umf_result = create_aligned_block(coarse, size, alignment, &curr);
if (umf_result != UMF_RESULT_SUCCESS) {
(void)free_blocks_re_add(coarse, curr);
goto err_unlock;
}
}

umf_result = coarse_add_used_block(coarse, *resultPtr, size);
if (umf_result != UMF_RESULT_SUCCESS) {
if (coarse->cb.free) {
coarse->cb.free(coarse->provider, *resultPtr, size);
if (action == ACTION_SPLIT) {
// Split the current block and put the new block after the one that we use.
umf_result = split_current_block(coarse, curr, size);
if (umf_result != UMF_RESULT_SUCCESS) {
(void)free_blocks_re_add(coarse, curr);
goto err_unlock;
}
goto err_unlock;

curr->size = size;

LOG_DEBUG("coarse_ALLOC (split_block) %zu used %zu alloc %zu", size,
coarse->used_size, coarse->alloc_size);

} else { // action == ACTION_USE
LOG_DEBUG("coarse_ALLOC (same_block) %zu used %zu alloc %zu", size,
coarse->used_size, coarse->alloc_size);
}

LOG_DEBUG("coarse_ALLOC (memory_provider) %zu used %zu alloc %zu", size,
coarse->used_size, coarse->alloc_size);
curr->used = true;
*resultPtr = curr->data;
coarse->used_size += size;

umf_result = UMF_RESULT_SUCCESS;

Expand Down
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