diff --git a/src/hotspot/share/gc/shared/space.cpp b/src/hotspot/share/gc/shared/space.cpp
index 82e32a17b43..31ff8a447c7 100644
--- a/src/hotspot/share/gc/shared/space.cpp
+++ b/src/hotspot/share/gc/shared/space.cpp
@@ -168,26 +168,6 @@ HeapWord* ContiguousSpace::block_start_const(const void* p) const {
   }
 }
 
-size_t ContiguousSpace::block_size(const HeapWord* p) const {
-  assert(MemRegion(bottom(), end()).contains(p),
-         "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")",
-         p2i(p), p2i(bottom()), p2i(end()));
-  HeapWord* current_top = top();
-  assert(p <= current_top,
-         "p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT,
-         p2i(p), p2i(current_top));
-  assert(p == current_top || oopDesc::is_oop(cast_to_oop(p)),
-         "p (" PTR_FORMAT ") is not a block start - "
-         "current_top: " PTR_FORMAT ", is_oop: %s",
-         p2i(p), p2i(current_top), BOOL_TO_STR(oopDesc::is_oop(cast_to_oop(p))));
-  if (p < current_top) {
-    return cast_to_oop(p)->size();
-  } else {
-    assert(p == current_top, "just checking");
-    return pointer_delta(end(), (HeapWord*) p);
-  }
-}
-
 // This version requires locking.
 inline HeapWord* ContiguousSpace::allocate_impl(size_t size) {
   assert(Heap_lock->owned_by_self() ||
diff --git a/src/hotspot/share/gc/shared/space.hpp b/src/hotspot/share/gc/shared/space.hpp
index 41c1d2a0d75..c60952d7b38 100644
--- a/src/hotspot/share/gc/shared/space.hpp
+++ b/src/hotspot/share/gc/shared/space.hpp
@@ -133,11 +133,6 @@ class Space: public CHeapObj<mtGC> {
   // object or a non-object.  If "p" is not in the space, return null.
   virtual HeapWord* block_start_const(const void* p) const = 0;
 
-  // Requires "addr" to be the start of a chunk, and returns its size.
-  // "addr + size" is required to be the start of a new chunk, or the end
-  // of the active area of the heap.
-  virtual size_t block_size(const HeapWord* addr) const = 0;
-
   // Allocation (return null if full).  Assumes the caller has established
   // mutually exclusive access to the space.
   virtual HeapWord* allocate(size_t word_size) = 0;
@@ -258,7 +253,6 @@ protected:
 
   // Very inefficient implementation.
   HeapWord* block_start_const(const void* p) const override;
-  size_t block_size(const HeapWord* p) const override;
 
   // Addresses for inlined allocation
   HeapWord** top_addr() { return &_top; }