--- libmalloc/libmalloc-317.40.8/src/magazine_medium.c
+++ libmalloc/libmalloc-317.100.9/src/magazine_medium.c
@@ -124,13 +124,13 @@
 {
 #if CONFIG_MEDIUM_USES_HYPER_SHIFT
 	if (os_likely(_os_cpu_number_override == -1)) {
-		return _os_cpu_number() >> hyper_shift;
+		return _malloc_cpu_number() >> hyper_shift;
 	} else {
 		return _os_cpu_number_override >> hyper_shift;
 	}
 #else // CONFIG_MEDIUM_USES_HYPER_SHIFT
 	if (os_likely(_os_cpu_number_override == -1)) {
-		return _os_cpu_number();
+		return _malloc_cpu_number();
 	} else {
 		return _os_cpu_number_override;
 	}
@@ -1070,19 +1070,31 @@
 	for (mag_index = 0; mag_index < rack->num_magazines; mag_index++) {
 		size_t index;
 		for (index = 0; index < rack->region_generation->num_regions_allocated; ++index) {
-			SZONE_LOCK(MEDIUM_SZONE_FROM_RACK(rack));
+			rack_region_lock(rack);
 
 			region_t medium = rack->region_generation->hashed_regions[index];
 			if (!medium || medium == HASHRING_REGION_DEALLOCATED) {
-				SZONE_UNLOCK(MEDIUM_SZONE_FROM_RACK(rack));
+				rack_region_unlock(rack);
 				continue;
 			}
 
+			region_trailer_t *trailer =
+					REGION_TRAILER_FOR_MEDIUM_REGION(medium);
+			// Make sure that the owning magazine doesn't try and take this out
+			// from under our feet.
+			trailer->dispose_flags |= RACK_DISPOSE_DELAY;
+			rack_region_unlock(rack);
+
 			magazine_t *mag_ptr = mag_lock_zine_for_region_trailer(rack->magazines,
-					REGION_TRAILER_FOR_MEDIUM_REGION(medium),
-					MAGAZINE_INDEX_FOR_MEDIUM_REGION(medium));
-
-			SZONE_UNLOCK(MEDIUM_SZONE_FROM_RACK(rack));
+					trailer, MAGAZINE_INDEX_FOR_MEDIUM_REGION(medium));
+
+			// If acquiring the region lock was enough to prevent the owning
+			// magazine from deallocating the region, free it now so we don't
+			// do wasted work.
+			if (rack_region_maybe_dispose(rack, medium, MEDIUM_REGION_SIZE, trailer)) {
+				SZONE_MAGAZINE_PTR_UNLOCK(mag_ptr);
+				continue;
+			}
 
 			/* Ordering is important here, the magazine of a region may potentially change
 			 * during mag_lock_zine_for_region_trailer, so src_mag_index must be taken
@@ -1357,24 +1369,10 @@
 	int objects_in_use = medium_free_detach_region(rack, depot_ptr, sparse_region);
 
 	if (0 == objects_in_use) {
-		// Invalidate the hash table entry for this region with HASHRING_REGION_DEALLOCATED.
-		// Using HASHRING_REGION_DEALLOCATED preserves the collision chain, using HASHRING_OPEN_ENTRY (0) would not.
-		rgnhdl_t pSlot = hash_lookup_region_no_lock(rack->region_generation->hashed_regions,
-													rack->region_generation->num_regions_allocated,
-													rack->region_generation->num_regions_allocated_shift,
-													sparse_region);
-		if (NULL == pSlot) {
-			malloc_zone_error(rack->debug_flags, true, "medium_free_try_depot_unmap_no_lock hash lookup failed: %p\n", sparse_region);
+		if (!rack_region_remove(rack, sparse_region, node)) {
 			return NULL;
 		}
-		*pSlot = HASHRING_REGION_DEALLOCATED;
 		depot_ptr->num_bytes_in_magazine -= MEDIUM_REGION_PAYLOAD_BYTES;
-		// Atomically increment num_regions_dealloc
-#ifdef __LP64___
-		OSAtomicIncrement64(&rack->num_regions_dealloc);
-#else
-		OSAtomicIncrement32((int32_t *)&rack->num_regions_dealloc);
-#endif
 
 		// Caller will transfer ownership of the region back to the OS with no locks held
 		MAGMALLOC_DEALLOCREGION(MEDIUM_SZONE_FROM_RACK(rack), (void *)sparse_region, (int)MEDIUM_REGION_SIZE); // DTrace USDT Probe