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stronger encoding of free lists using two keys per page

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This commit is contained in:
daan 2019-12-27 23:33:50 -08:00
parent ce02986d56
commit e3391d9a53
8 changed files with 83 additions and 50 deletions
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8
src/alloc.c
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@ -157,7 +157,7 @@ static mi_decl_noinline bool mi_check_is_double_freex(const mi_page_t* page, con
}
static inline bool mi_check_is_double_free(const mi_page_t* page, const mi_block_t* block) {
mi_block_t* n = mi_block_nextx(page, block, page->cookie); // pretend it is freed, and get the decoded first field
mi_block_t* n = mi_block_nextx(page, block, page->key[0], page->key[1]); // pretend it is freed, and get the decoded first field
if (((uintptr_t)n & (MI_INTPTR_SIZE-1))==0 && // quick check: aligned pointer?
(n==NULL || mi_is_in_same_segment(block, n))) // quick check: in same segment or NULL?
{
@ -242,7 +242,7 @@ static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* bloc
mi_block_t* dfree;
do {
dfree = (mi_block_t*)heap->thread_delayed_free;
mi_block_set_nextx(heap,block,dfree, heap->cookie);
mi_block_set_nextx(heap,block,dfree, heap->key[0], heap->key[1]);
} while (!mi_atomic_cas_ptr_weak(mi_atomic_cast(void*,&heap->thread_delayed_free), block, dfree));
}
@ -266,7 +266,7 @@ static inline void _mi_free_block(mi_page_t* page, bool local, mi_block_t* block
// and push it on the free list
if (mi_likely(local)) {
// owning thread can free a block directly
if (mi_check_is_double_free(page, block)) return;
if (mi_unlikely(mi_check_is_double_free(page, block))) return;
mi_block_set_next(page, block, page->local_free);
page->local_free = block;
page->used--;
@ -341,7 +341,7 @@ void mi_free(void* p) mi_attr_noexcept
if (mi_likely(tid == segment->thread_id && page->flags.full_aligned == 0)) { // the thread id matches and it is not a full page, nor has aligned blocks
// local, and not full or aligned
mi_block_t* block = (mi_block_t*)p;
if (mi_check_is_double_free(page,block)) return;
if (mi_unlikely(mi_check_is_double_free(page,block))) return;
mi_block_set_next(page, block, page->local_free);
page->local_free = block;
page->used--;