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initial working large alignment

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daan
2022-11-05 16:40:42 -07:00
parent 6a80fa3ac1
commit 4b91ff760d
7 changed files with 67 additions and 28 deletions
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50
src/alloc-aligned.c
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@@ -18,41 +18,59 @@ terms of the MIT license. A copy of the license can be found in the file
static mi_decl_noinline void* mi_heap_malloc_zero_aligned_at_fallback(mi_heap_t* const heap, const size_t size, const size_t alignment, const size_t offset, const bool zero) mi_attr_noexcept
{
mi_assert_internal(size <= PTRDIFF_MAX);
mi_assert_internal(alignment!=0 && _mi_is_power_of_two(alignment) && alignment <= MI_ALIGNMENT_MAX);
mi_assert_internal(alignment != 0 && _mi_is_power_of_two(alignment));
const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)`
const uintptr_t align_mask = alignment - 1; // for any x, `(x & align_mask) == (x % alignment)`
const size_t padsize = size + MI_PADDING_SIZE;
// use regular allocation if it is guaranteed to fit the alignment constraints
if (offset==0 && alignment<=padsize && padsize<=MI_MEDIUM_OBJ_SIZE_MAX && (padsize&align_mask)==0) {
if (offset == 0 && alignment <= padsize && padsize <= MI_MEDIUM_OBJ_SIZE_MAX && (padsize & align_mask) == 0) {
void* p = _mi_heap_malloc_zero(heap, size, zero);
mi_assert_internal(p == NULL || ((uintptr_t)p % alignment) == 0);
return p;
}
// otherwise over-allocate
const size_t oversize = size + alignment - 1;
void* p = _mi_heap_malloc_zero(heap, oversize, zero);
if (p == NULL) return NULL;
void* p;
size_t oversize;
if mi_unlikely(alignment > MI_ALIGNMENT_MAX) {
// use OS allocation for very large alignment and allocate inside a huge page (dedicated segment with 1 page)
if mi_unlikely(offset != 0) {
// todo: cannot support offset alignment for very large alignments yet
#if MI_DEBUG > 0
_mi_error_message(EOVERFLOW, "aligned allocation with a very large alignment cannot be used with an alignment offset (size %zu, alignment %zu, offset %zu)\n", size, alignment, offset);
#endif
return NULL;
}
oversize = size + MI_SEGMENT_SIZE - 1;
p = _mi_heap_malloc_zero_ex(heap, oversize, zero, alignment);
if (p == NULL) return NULL;
//mi_assert_internal(_mi_is_aligned(p, alignment));
}
else {
// otherwise over-allocate
oversize = size + alignment - 1;
p = _mi_heap_malloc_zero(heap, oversize, zero);
if (p == NULL) return NULL;
}
// .. and align within the allocation
uintptr_t adjust = alignment - (((uintptr_t)p + offset) & align_mask);
mi_assert_internal(adjust <= alignment);
void* aligned_p = (adjust == alignment ? p : (void*)((uintptr_t)p + adjust));
if (aligned_p != p) mi_page_set_has_aligned(_mi_ptr_page(p), true);
mi_assert_internal(((uintptr_t)aligned_p + offset) % alignment == 0);
mi_assert_internal(p == _mi_page_ptr_unalign(_mi_ptr_segment(aligned_p), _mi_ptr_page(aligned_p), aligned_p));
mi_assert_internal(((uintptr_t)aligned_p + offset) % alignment == 0);
#if MI_TRACK_ENABLED
if (p != aligned_p) {
mi_track_free(p);
mi_track_malloc(aligned_p,size,zero);
mi_track_malloc(aligned_p, size, zero);
}
else {
mi_track_resize(aligned_p,oversize,size);
mi_track_resize(aligned_p, oversize, size);
}
#endif
return aligned_p;
return aligned_p;
}
// Primitive aligned allocation
@@ -60,18 +78,20 @@ static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t
{
// note: we don't require `size > offset`, we just guarantee that the address at offset is aligned regardless of the allocated size.
mi_assert(alignment > 0);
if mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment)) { // require power-of-two (see <https://en.cppreference.com/w/c/memory/aligned_alloc>)
if mi_unlikely(alignment == 0 || !_mi_is_power_of_two(alignment)) { // require power-of-two (see <https://en.cppreference.com/w/c/memory/aligned_alloc>)
#if MI_DEBUG > 0
_mi_error_message(EOVERFLOW, "aligned allocation requires the alignment to be a power-of-two (size %zu, alignment %zu)\n", size, alignment);
#endif
return NULL;
}
/*
if mi_unlikely(alignment > MI_ALIGNMENT_MAX) { // we cannot align at a boundary larger than this (or otherwise we cannot find segment headers)
#if MI_DEBUG > 0
_mi_error_message(EOVERFLOW, "aligned allocation has a maximum alignment of %zu (size %zu, alignment %zu)\n", MI_ALIGNMENT_MAX, size, alignment);
#endif
return NULL;
}
*/
if mi_unlikely(size > PTRDIFF_MAX) { // we don't allocate more than PTRDIFF_MAX (see <https://sourceware.org/ml/libc-announce/2019/msg00001.html>)
#if MI_DEBUG > 0
_mi_error_message(EOVERFLOW, "aligned allocation request is too large (size %zu, alignment %zu)\n", size, alignment);
@@ -82,7 +102,7 @@ static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t
const size_t padsize = size + MI_PADDING_SIZE; // note: cannot overflow due to earlier size > PTRDIFF_MAX check
// try first if there happens to be a small block available with just the right alignment
if mi_likely(padsize <= MI_SMALL_SIZE_MAX) {
if mi_likely(padsize <= MI_SMALL_SIZE_MAX && alignment <= padsize) {
mi_page_t* page = _mi_heap_get_free_small_page(heap, padsize);
const bool is_aligned = (((uintptr_t)page->free+offset) & align_mask)==0;
if mi_likely(page->free != NULL && is_aligned)