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initial progress on removing alignment limit

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daan 2022-11-05 14:46:52 -07:00
parent fe61be80bf
commit 6a80fa3ac1
11 changed files with 114 additions and 51 deletions
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37
src/os.c
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@ -840,8 +840,45 @@ void* _mi_os_alloc_aligned(size_t size, size_t alignment, bool commit, bool* lar
return mi_os_mem_alloc_aligned(size, alignment, commit, allow_large, (large!=NULL?large:&allow_large), &_mi_stats_main /*tld->stats*/ );
}
/* -----------------------------------------------------------
OS aligned allocation with an offset. This is used
for large alignments > MI_SEGMENT_SIZE so we can align
the first page at an offset from the start of the segment.
As we may need to overallocate, we need to free such pointers
using `mi_free_aligned` to use the actual start of the
memory region.
----------------------------------------------------------- */
void* _mi_os_alloc_aligned_offset(size_t size, size_t alignment, size_t offset, bool commit, bool* large, mi_stats_t* tld_stats) {
mi_assert(offset <= MI_SEGMENT_SIZE);
mi_assert(offset <= size);
mi_assert((alignment % _mi_os_page_size()) == 0);
if (offset > MI_SEGMENT_SIZE) return NULL;
if (offset == 0) {
return _mi_os_alloc_aligned(size, alignment, commit, large, tld_stats);
}
else {
const size_t extra = _mi_align_up(offset, alignment) - offset;
const size_t oversize = size + extra;
void* start = _mi_os_alloc_aligned(oversize, alignment, commit, large, tld_stats);
if (start == NULL) return NULL;
void* p = (uint8_t*)start + extra;
mi_assert(_mi_is_aligned((uint8_t*)p + offset, alignment));
if (commit && extra > _mi_os_page_size()) {
_mi_os_decommit(start, extra, tld_stats);
}
return p;
}
}
void _mi_os_free_aligned(void* p, size_t size, size_t alignment, size_t align_offset, bool was_committed, mi_stats_t* tld_stats) {
mi_assert(align_offset <= MI_SEGMENT_SIZE);
const size_t extra = _mi_align_up(align_offset, alignment) - align_offset;
void* start = (uint8_t*)p - extra;
_mi_os_free_ex(start, size + extra, was_committed, tld_stats);
}
/* -----------------------------------------------------------
OS memory API: reset, commit, decommit, protect, unprotect.
----------------------------------------------------------- */