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decommit unused prefix of large aligned blocks

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This commit is contained in:
daan 2022-11-07 16:41:40 -08:00
parent 27fc2cf17e
commit 2479d168ad
5 changed files with 63 additions and 28 deletions
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41
src/alloc.c
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@ -51,7 +51,9 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
}
#if (MI_DEBUG>0) && !MI_TRACK_ENABLED
if (!page->is_zero && !zero) { memset(block, MI_DEBUG_UNINIT, mi_page_usable_block_size(page)); }
if (!page->is_zero && !zero && !mi_page_is_huge(page)) {
memset(block, MI_DEBUG_UNINIT, mi_page_usable_block_size(page));
}
#elif (MI_SECURE!=0)
if (!zero) { block->next = 0; } // don't leak internal data
#endif
@ -77,9 +79,11 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
#endif
padding->canary = (uint32_t)(mi_ptr_encode(page,block,page->keys));
padding->delta = (uint32_t)(delta);
uint8_t* fill = (uint8_t*)padding - delta;
const size_t maxpad = (delta > MI_MAX_ALIGN_SIZE ? MI_MAX_ALIGN_SIZE : delta); // set at most N initial padding bytes
for (size_t i = 0; i < maxpad; i++) { fill[i] = MI_DEBUG_PADDING; }
if (!mi_page_is_huge(page)) {
uint8_t* fill = (uint8_t*)padding - delta;
const size_t maxpad = (delta > MI_MAX_ALIGN_SIZE ? MI_MAX_ALIGN_SIZE : delta); // set at most N initial padding bytes
for (size_t i = 0; i < maxpad; i++) { fill[i] = MI_DEBUG_PADDING; }
}
#endif
return block;
@ -250,17 +254,19 @@ static bool mi_verify_padding(const mi_page_t* page, const mi_block_t* block, si
if (!ok) return false;
mi_assert_internal(bsize >= delta);
*size = bsize - delta;
uint8_t* fill = (uint8_t*)block + bsize - delta;
const size_t maxpad = (delta > MI_MAX_ALIGN_SIZE ? MI_MAX_ALIGN_SIZE : delta); // check at most the first N padding bytes
mi_track_mem_defined(fill,maxpad);
for (size_t i = 0; i < maxpad; i++) {
if (fill[i] != MI_DEBUG_PADDING) {
*wrong = bsize - delta + i;
ok = false;
break;
if (!mi_page_is_huge(page)) {
uint8_t* fill = (uint8_t*)block + bsize - delta;
const size_t maxpad = (delta > MI_MAX_ALIGN_SIZE ? MI_MAX_ALIGN_SIZE : delta); // check at most the first N padding bytes
mi_track_mem_defined(fill, maxpad);
for (size_t i = 0; i < maxpad; i++) {
if (fill[i] != MI_DEBUG_PADDING) {
*wrong = bsize - delta + i;
ok = false;
break;
}
}
mi_track_mem_noaccess(fill, maxpad);
}
mi_track_mem_noaccess(fill,maxpad);
return ok;
}
@ -361,10 +367,7 @@ static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* bloc
// that is safe as these are constant and the page won't be freed (as the block is not freed yet).
mi_check_padding(page, block);
mi_padding_shrink(page, block, sizeof(mi_block_t)); // for small size, ensure we can fit the delayed thread pointers without triggering overflow detection
#if (MI_DEBUG!=0) && !MI_TRACK_ENABLED // note: when tracking, cannot use mi_usable_size with multi-threading
memset(block, MI_DEBUG_FREED, mi_usable_size(block));
#endif
// huge page segments are always abandoned and can be freed immediately
mi_segment_t* const segment = _mi_page_segment(page);
if (segment->page_kind==MI_PAGE_HUGE) {
@ -373,6 +376,10 @@ static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* bloc
return;
}
#if (MI_DEBUG!=0) && !MI_TRACK_ENABLED // note: when tracking, cannot use mi_usable_size with multi-threading
memset(block, MI_DEBUG_FREED, mi_usable_size(block));
#endif
// Try to put the block on either the page-local thread free list, or the heap delayed free list.
mi_thread_free_t tfreex;
bool use_delayed;