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merge from dev improved aligned allocation

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Daan 2024-05-11 07:08:48 -07:00
commit e8206e9f6f
8 changed files with 89 additions and 63 deletions
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4
include/mimalloc/internal.h
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@ -199,7 +199,9 @@ mi_msecs_t _mi_clock_end(mi_msecs_t start);
mi_msecs_t _mi_clock_start(void);
// "alloc.c"
void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size, bool zero) mi_attr_noexcept; // called from `_mi_malloc_generic`
void* _mi_page_malloc_zero(mi_heap_t* heap, mi_page_t* page, size_t size, bool zero) mi_attr_noexcept; // called from `_mi_malloc_generic`
void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size) mi_attr_noexcept; // called from `_mi_heap_malloc_aligned`
void* _mi_page_malloc_zeroed(mi_heap_t* heap, mi_page_t* page, size_t size) mi_attr_noexcept; // called from `_mi_heap_malloc_aligned`
void* _mi_heap_malloc_zero(mi_heap_t* heap, size_t size, bool zero) mi_attr_noexcept;
void* _mi_heap_malloc_zero_ex(mi_heap_t* heap, size_t size, bool zero, size_t huge_alignment) mi_attr_noexcept; // called from `_mi_heap_malloc_aligned`
void* _mi_heap_realloc_zero(mi_heap_t* heap, void* p, size_t newsize, bool zero) mi_attr_noexcept;

4
include/mimalloc/types.h
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@ -203,8 +203,8 @@ typedef int32_t mi_ssize_t;
#error "mimalloc internal: define more bins"
#endif
// blocks up to this size are always allocated aligned
#define MI_MAX_ALIGN_GUARANTEE (8*MI_MAX_ALIGN_SIZE)
// Maximum block size for which blocks are guaranteed to be block size aligned. (see `segment.c:_mi_segment_page_start`)
#define MI_MAX_ALIGN_GUARANTEE (MI_MEDIUM_OBJ_SIZE_MAX)
// Alignments over MI_BLOCK_ALIGNMENT_MAX are allocated in dedicated huge page segments
#define MI_BLOCK_ALIGNMENT_MAX (MI_SEGMENT_SIZE >> 1)

75
src/alloc-aligned.c
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@ -15,15 +15,15 @@ terms of the MIT license. A copy of the license can be found in the file
// Aligned Allocation
// ------------------------------------------------------
static inline bool mi_is_naturally_aligned( size_t size, size_t alignment ) {
static bool mi_malloc_is_naturally_aligned( size_t size, size_t alignment ) {
// objects up to `MI_MAX_ALIGN_GUARANTEE` are allocated aligned to their size (see `segment.c:_mi_segment_page_start`).
// note: the size may not be not an actual bin-size but it turns out the test below is still correct for our
// powers of two bin spacing (see test-api.c:test-aligned13).
mi_assert_internal(_mi_is_power_of_two(alignment) && (alignment > 0));
return (size <= (MI_MAX_ALIGN_GUARANTEE - MI_PADDING_SIZE) && alignment <= size && ((size + MI_PADDING_SIZE) & (alignment-1)) == 0);
if (alignment > size) return false;
if (alignment <= MI_MAX_ALIGN_SIZE) return true;
const size_t bsize = mi_good_size(size);
return (bsize <= MI_MAX_ALIGN_GUARANTEE && (bsize & (alignment-1)) == 0);
}
// Fallback primitive aligned allocation -- split out for better codegen
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
{
@ -31,10 +31,18 @@ static mi_decl_noinline void* mi_heap_malloc_zero_aligned_at_fallback(mi_heap_t*
mi_assert_internal(alignment != 0 && _mi_is_power_of_two(alignment));
// use regular allocation if it is guaranteed to fit the alignment constraints.
if (offset == 0 && mi_is_naturally_aligned(size,alignment)) {
if (offset == 0 && mi_malloc_is_naturally_aligned(size,alignment)) {
void* p = _mi_heap_malloc_zero(heap, size, zero);
mi_assert_internal(p == NULL || ((uintptr_t)p % alignment) == 0);
return p;
const bool is_aligned_or_null = (((uintptr_t)p) & (alignment-1))==0;
if mi_likely(is_aligned_or_null) {
return p;
}
else {
// this should never happen if the `mi_malloc_is_naturally_aligned` check is correct..
mi_assert(false);
mi_free(p);
}
}
void* p;
@ -83,7 +91,7 @@ static mi_decl_noinline void* mi_heap_malloc_zero_aligned_at_fallback(mi_heap_t*
// now zero the block if needed
if (alignment > MI_BLOCK_ALIGNMENT_MAX) {
// for the tracker, on huge aligned allocations only from the start of the large block is defined
// for the tracker, on huge aligned allocations only the memory from the start of the large block is defined
mi_track_mem_undefined(aligned_p, size);
if (zero) {
_mi_memzero_aligned(aligned_p, mi_usable_size(aligned_p));
@ -106,33 +114,35 @@ static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t
#endif
return NULL;
}
// try first if there happens to be a small block available with just the right alignment
if mi_likely(size <= MI_SMALL_SIZE_MAX && alignment <= size) {
const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)`
const size_t padsize = size + MI_PADDING_SIZE;
mi_page_t* page = _mi_heap_get_free_small_page(heap, padsize);
if mi_likely(page->free != NULL) {
const bool is_aligned = (((uintptr_t)page->free + offset) & align_mask)==0;
if mi_likely(is_aligned)
{
#if MI_STAT>1
mi_heap_stat_increase(heap, malloc, size);
#endif
void* p = (zero ? _mi_page_malloc_zeroed(heap,page,padsize) : _mi_page_malloc(heap,page,padsize)); // call specific page malloc for better codegen
mi_assert_internal(p != NULL);
mi_assert_internal(((uintptr_t)p + offset) % alignment == 0);
mi_track_malloc(p,size,zero);
return p;
}
}
}
// fallback
if mi_unlikely(size > (MI_MAX_ALLOC_SIZE - MI_PADDING_SIZE)) { // we don't allocate more than MI_MAX_ALLOC_SIZE (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);
#endif
return NULL;
}
const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)`
const size_t padsize = size + MI_PADDING_SIZE; // note: cannot overflow due to earlier size 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 && 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)
{
#if MI_STAT>1
mi_heap_stat_increase(heap, malloc, size);
#endif
void* p = _mi_page_malloc(heap, page, padsize, zero); // TODO: inline _mi_page_malloc
mi_assert_internal(p != NULL);
mi_assert_internal(((uintptr_t)p + offset) % alignment == 0);
mi_track_malloc(p,size,zero);
return p;
}
}
// fallback
return mi_heap_malloc_zero_aligned_at_fallback(heap, size, alignment, offset, zero);
}
@ -146,14 +156,7 @@ mi_decl_nodiscard mi_decl_restrict void* mi_heap_malloc_aligned_at(mi_heap_t* he
}
mi_decl_nodiscard mi_decl_restrict void* mi_heap_malloc_aligned(mi_heap_t* heap, size_t size, size_t alignment) mi_attr_noexcept {
if (alignment == 0 || !_mi_is_power_of_two(alignment)) return NULL;
if (size <= MI_SMALL_SIZE_MAX && mi_is_naturally_aligned(size,alignment)) {
// fast path for common alignment and size
return mi_heap_malloc_small(heap, size);
}
else {
return mi_heap_malloc_aligned_at(heap, size, alignment, 0);
}
return mi_heap_malloc_aligned_at(heap, size, alignment, 0);
}
// ensure a definition is emitted

22
src/alloc.c
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@ -28,7 +28,7 @@ terms of the MIT license. A copy of the license can be found in the file
// Fast allocation in a page: just pop from the free list.
// Fall back to generic allocation only if the list is empty.
// Note: in release mode the (inlined) routine is about 7 instructions with a single test.
extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size, bool zero) mi_attr_noexcept
extern inline void* _mi_page_malloc_zero(mi_heap_t* heap, mi_page_t* page, size_t size, bool zero) mi_attr_noexcept
{
mi_assert_internal(page->block_size == 0 /* empty heap */ || mi_page_block_size(page) >= size);
mi_block_t* const block = page->free;
@ -85,14 +85,14 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
#endif
#if MI_PADDING // && !MI_TRACK_ENABLED
mi_padding_t* const padding = (mi_padding_t*)((uint8_t*)block + mi_page_usable_block_size(page));
ptrdiff_t delta = ((uint8_t*)padding - (uint8_t*)block - (size - MI_PADDING_SIZE));
mi_padding_t* const padding = (mi_padding_t*)((uint8_t*)block + mi_page_usable_block_size(page));
ptrdiff_t delta = ((uint8_t*)padding - (uint8_t*)block - (size - MI_PADDING_SIZE));
#if (MI_DEBUG>=2)
mi_assert_internal(delta >= 0 && mi_page_usable_block_size(page) >= (size - MI_PADDING_SIZE + delta));
#endif
mi_track_mem_defined(padding,sizeof(mi_padding_t)); // note: re-enable since mi_page_usable_block_size may set noaccess
padding->canary = (uint32_t)(mi_ptr_encode(page,block,page->keys));
padding->delta = (uint32_t)(delta);
mi_track_mem_defined(padding,sizeof(mi_padding_t)); // note: re-enable since mi_page_usable_block_size may set noaccess
padding->canary = (uint32_t)(mi_ptr_encode(page,block,page->keys));
padding->delta = (uint32_t)(delta);
#if MI_PADDING_CHECK
if (!mi_page_is_huge(page)) {
uint8_t* fill = (uint8_t*)padding - delta;
@ -105,6 +105,14 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
return block;
}
// extra entries for improved efficiency in `alloc-aligned.c`.
extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size) mi_attr_noexcept {
return _mi_page_malloc_zero(heap,page,size,false);
}
extern inline void* _mi_page_malloc_zeroed(mi_heap_t* heap, mi_page_t* page, size_t size) mi_attr_noexcept {
return _mi_page_malloc_zero(heap,page,size,true);
}
static inline mi_decl_restrict void* mi_heap_malloc_small_zero(mi_heap_t* heap, size_t size, bool zero) mi_attr_noexcept {
mi_assert(heap != NULL);
#if MI_DEBUG
@ -117,7 +125,7 @@ static inline mi_decl_restrict void* mi_heap_malloc_small_zero(mi_heap_t* heap,
#endif
mi_page_t* page = _mi_heap_get_free_small_page(heap, size + MI_PADDING_SIZE);
void* const p = _mi_page_malloc(heap, page, size + MI_PADDING_SIZE, zero);
void* const p = _mi_page_malloc_zero(heap, page, size + MI_PADDING_SIZE, zero);
mi_track_malloc(p,size,zero);
#if MI_STAT>1

4
src/page-queue.c
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@ -113,10 +113,10 @@ size_t _mi_bin_size(uint8_t bin) {
// Good size for allocation
size_t mi_good_size(size_t size) mi_attr_noexcept {
if (size <= MI_MEDIUM_OBJ_SIZE_MAX) {
return _mi_bin_size(mi_bin(size));
return _mi_bin_size(mi_bin(size + MI_PADDING_SIZE));
}
else {
return _mi_align_up(size,_mi_os_page_size());
return _mi_align_up(size + MI_PADDING_SIZE,_mi_os_page_size());
}
}

4
src/page.c
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@ -932,12 +932,12 @@ void* _mi_malloc_generic(mi_heap_t* heap, size_t size, bool zero, size_t huge_al
// and try again, this time succeeding! (i.e. this should never recurse through _mi_page_malloc)
if mi_unlikely(zero && page->block_size == 0) {
// note: we cannot call _mi_page_malloc with zeroing for huge blocks; we zero it afterwards in that case.
void* p = _mi_page_malloc(heap, page, size, false);
void* p = _mi_page_malloc(heap, page, size);
mi_assert_internal(p != NULL);
_mi_memzero_aligned(p, mi_page_usable_block_size(page));
return p;
}
else {
return _mi_page_malloc(heap, page, size, zero);
return _mi_page_malloc_zero(heap, page, size, zero);
}
}

24
src/segment.c
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@ -312,20 +312,28 @@ static size_t mi_segment_info_size(mi_segment_t* segment) {
return segment->segment_info_slices * MI_SEGMENT_SLICE_SIZE;
}
static uint8_t* _mi_segment_page_start_from_slice(const mi_segment_t* segment, const mi_slice_t* slice, size_t xblock_size, size_t* page_size)
static uint8_t* _mi_segment_page_start_from_slice(const mi_segment_t* segment, const mi_slice_t* slice, size_t block_size, size_t* page_size)
{
ptrdiff_t idx = slice - segment->slices;
size_t psize = (size_t)slice->slice_count * MI_SEGMENT_SLICE_SIZE;
const ptrdiff_t idx = slice - segment->slices;
const size_t psize = (size_t)slice->slice_count * MI_SEGMENT_SLICE_SIZE;
uint8_t* const pstart = (uint8_t*)segment + (idx*MI_SEGMENT_SLICE_SIZE);
// make the start not OS page aligned for smaller blocks to avoid page/cache effects
// note: the offset must always be an xblock_size multiple since we assume small allocations
// note: the offset must always be a block_size multiple since we assume small allocations
// are aligned (see `mi_heap_malloc_aligned`).
size_t start_offset = 0;
if (xblock_size >= MI_INTPTR_SIZE) {
if (xblock_size <= 64) { start_offset = 3*xblock_size; }
else if (xblock_size <= 512) { start_offset = xblock_size; }
if (block_size > 0 && block_size <= MI_MAX_ALIGN_GUARANTEE) {
// for small objects, ensure the page start is aligned with the block size (PR#66 by kickunderscore)
const size_t adjust = block_size - ((uintptr_t)pstart % block_size);
if (adjust < block_size && psize >= block_size + adjust) {
start_offset += adjust;
}
}
if (block_size >= MI_INTPTR_SIZE) {
if (block_size <= 64) { start_offset += 3*block_size; }
else if (block_size <= 512) { start_offset += block_size; }
}
if (page_size != NULL) { *page_size = psize - start_offset; }
return (uint8_t*)segment + ((idx*MI_SEGMENT_SLICE_SIZE) + start_offset);
return (pstart + start_offset);
}
// Start of the page available memory; can be used on uninitialized pages

15
test/test-api.c
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@ -232,15 +232,20 @@ int main(void) {
}
CHECK_BODY("mimalloc-aligned13") {
bool ok = true;
for( size_t size = 1; size <= MI_SMALL_SIZE_MAX && ok; size++ ) {
for( size_t size = 1; size <= (MI_SMALL_SIZE_MAX * 2) && ok; size++ ) {
for(size_t align = 1; align <= size && ok; align *= 2 ) {
void* p = mi_malloc_aligned(size,align);
ok = (p != NULL && ((uintptr_t)p % align) == 0);
mi_free(p);
void* p[10];
for(int i = 0; i < 10 && ok; i++) {
p[i] = mi_malloc_aligned(size,align);;
ok = (p[i] != NULL && ((uintptr_t)(p[i]) % align) == 0);
}
for(int i = 0; i < 10 && ok; i++) {
mi_free(p[i]);
}
/*
if (ok && align <= size && ((size + MI_PADDING_SIZE) & (align-1)) == 0) {
size_t bsize = mi_good_size(size);
ok = (align <= bsize && ((bsize + MI_PADDING_SIZE) & (align-1)) == 0);
ok = (align <= bsize && (bsize & (align-1)) == 0);
}
*/
}