diff --git a/src/heap/sharedMem.ml b/src/heap/sharedMem.ml
index 600e272..511b724 100644
--- a/src/heap/sharedMem.ml
+++ b/src/heap/sharedMem.ml
@@ -521,7 +521,7 @@ end = struct
 
     let stack: t option ref = ref None
 
-    let has_local_changes () = Core_kernel.Option.is_some (!stack)
+    let has_local_changes () = Core.Option.is_some (!stack)
 
     let rec mem stack_opt key =
       match stack_opt with
diff --git a/src/interface/memory.ml b/src/interface/memory.ml
index 3554b17..09aa1f5 100644
--- a/src/interface/memory.ml
+++ b/src/interface/memory.ml
@@ -66,10 +66,10 @@ let get_heap_handle () =
 
 
 let heap_use_ratio () =
-  Core_kernel.Float.of_int (SharedMemory.heap_size ()) /.
-  Core_kernel.Float.of_int initial_heap_size
+  Core.Float.of_int (SharedMemory.heap_size ()) /.
+  Core.Float.of_int initial_heap_size
 
 
 let slot_use_ratio () =
   let { SharedMemory.used_slots; slots; _ } = SharedMemory.hash_stats () in
-  Core_kernel.Float.of_int used_slots /. Core_kernel.Float.of_int slots
+  Core.Float.of_int used_slots /. Core.Float.of_int slots
diff --git a/src/interface/scheduler.ml b/src/interface/scheduler.ml
index 9b8282a..b5d41b5 100644
--- a/src/interface/scheduler.ml
+++ b/src/interface/scheduler.ml
@@ -48,7 +48,7 @@ let map_reduce
     | Some exact_size when exact_size > 0 ->
       (List.length work / exact_size) + 1
     | _ ->
-      let bucket_multiplier = Core_kernel.Int.min bucket_multiplier (1 + (List.length work / 400)) in
+      let bucket_multiplier = Core.Int.min bucket_multiplier (1 + (List.length work / 400)) in
       number_of_workers * bucket_multiplier
   in
   MultiWorker.call
diff --git a/src/utils/dune b/src/utils/dune
index 50a4c42..45e4a5a 100644
--- a/src/utils/dune
+++ b/src/utils/dune
@@ -15,6 +15,7 @@
     sysinfo)
   (libraries
     core
+    core_unix
     str
     hack_parallel.collections
     hack_parallel.disk
diff --git a/src/utils/hh_logger.ml b/src/utils/hh_logger.ml
index 4c99f05..8075ed5 100644
--- a/src/utils/hh_logger.ml
+++ b/src/utils/hh_logger.ml
@@ -9,6 +9,7 @@
 *)
 
 open Core
+module Unix = Core_unix
 
 let timestamp_string () =
   let open Unix in