diff options
Diffstat (limited to 'src/page.c')
| -rw-r--r-- | src/page.c | 26 |
1 files changed, 21 insertions, 5 deletions
@@ -123,15 +123,18 @@ bool _mi_page_is_valid(mi_page_t* page) { } #endif -void _mi_page_use_delayed_free(mi_page_t* page, mi_delayed_t delay, bool override_never) { +bool _mi_page_use_delayed_free(mi_page_t* page, mi_delayed_t delay, bool override_never) { mi_thread_free_t tfreex; mi_delayed_t old_delay; mi_thread_free_t tfree; + size_t yield_count = 0; do { tfree = mi_atomic_load_acquire(&page->xthread_free); // note: must acquire as we can break/repeat this loop and not do a CAS; tfreex = mi_tf_set_delayed(tfree, delay); old_delay = mi_tf_delayed(tfree); if mi_unlikely(old_delay == MI_DELAYED_FREEING) { + if (yield_count >= 4) return false; // give up after 4 tries + yield_count++; mi_atomic_yield(); // delay until outstanding MI_DELAYED_FREEING are done. // tfree = mi_tf_set_delayed(tfree, MI_NO_DELAYED_FREE); // will cause CAS to busy fail } @@ -143,6 +146,8 @@ void _mi_page_use_delayed_free(mi_page_t* page, mi_delayed_t delay, bool overrid } } while ((old_delay == MI_DELAYED_FREEING) || !mi_atomic_cas_weak_release(&page->xthread_free, &tfree, tfreex)); + + return true; // success } /* ----------------------------------------------------------- @@ -272,10 +277,18 @@ static mi_page_t* mi_page_fresh(mi_heap_t* heap, mi_page_queue_t* pq) { Do any delayed frees (put there by other threads if they deallocated in a full page) ----------------------------------------------------------- */ -void _mi_heap_delayed_free(mi_heap_t* heap) { +void _mi_heap_delayed_free_all(mi_heap_t* heap) { + while (!_mi_heap_delayed_free_partial(heap)) { + mi_atomic_yield(); + } +} + +// returns true if all delayed frees were processed +bool _mi_heap_delayed_free_partial(mi_heap_t* heap) { // take over the list (note: no atomic exchange since it is often NULL) mi_block_t* block = mi_atomic_load_ptr_relaxed(mi_block_t, &heap->thread_delayed_free); while (block != NULL && !mi_atomic_cas_ptr_weak_acq_rel(mi_block_t, &heap->thread_delayed_free, &block, NULL)) { /* nothing */ }; + bool all_freed = true; // and free them all while(block != NULL) { @@ -283,7 +296,9 @@ void _mi_heap_delayed_free(mi_heap_t* heap) { // use internal free instead of regular one to keep stats etc correct if (!_mi_free_delayed_block(block)) { // we might already start delayed freeing while another thread has not yet - // reset the delayed_freeing flag; in that case delay it further by reinserting. + // reset the delayed_freeing flag; in that case delay it further by reinserting the current block + // into the delayed free list + all_freed = false; mi_block_t* dfree = mi_atomic_load_ptr_relaxed(mi_block_t, &heap->thread_delayed_free); do { mi_block_set_nextx(heap, block, dfree, heap->keys); @@ -291,6 +306,7 @@ void _mi_heap_delayed_free(mi_heap_t* heap) { } block = next; } + return all_freed; } /* ----------------------------------------------------------- @@ -847,8 +863,8 @@ void* _mi_malloc_generic(mi_heap_t* heap, size_t size, bool zero) mi_attr_noexce // call potential deferred free routines _mi_deferred_free(heap, false); - // free delayed frees from other threads - _mi_heap_delayed_free(heap); + // free delayed frees from other threads (but skip contended ones) + _mi_heap_delayed_free_partial(heap); // find (or allocate) a page of the right size mi_page_t* page = mi_find_page(heap, size); |