diff --git a/gc.c b/gc.c
index 6c4bffa95d..34334f3278 100644
--- a/gc.c
+++ b/gc.c
@@ -9647,11 +9647,55 @@ gc_start_internal(rb_execution_context_t *ec, VALUE self, VALUE full_mark, VALUE
     return Qnil;
 }
 
+static void
+free_empty_pages(void)
+{
+    rb_objspace_t *objspace = &rb_objspace;
+
+    for (int i = 0; i < SIZE_POOL_COUNT; i++) {
+        /* Move all empty pages to the tomb heap for freeing. */
+        rb_size_pool_t *size_pool = &size_pools[i];
+        rb_heap_t *heap = SIZE_POOL_EDEN_HEAP(size_pool);
+        rb_heap_t *tomb_heap = SIZE_POOL_TOMB_HEAP(size_pool);
+
+        size_t freed_pages = 0;
+
+        struct heap_page **next_page_ptr = &heap->free_pages;
+        struct heap_page *page = heap->free_pages;
+        while (page) {
+            /* All finalizers should have been ran in gc_start_internal, so there
+            * should be no objects that require finalization. */
+            GC_ASSERT(page->final_slots == 0);
+
+            struct heap_page *next_page = page->free_next;
+
+            if (page->free_slots == page->total_slots) {
+                heap_unlink_page(objspace, heap, page);
+                heap_add_page(objspace, size_pool, tomb_heap, page);
+                freed_pages++;
+            }
+            else {
+                *next_page_ptr = page;
+                next_page_ptr = &page->free_next;
+            }
+
+            page = next_page;
+        }
+
+        *next_page_ptr = NULL;
+
+        size_pool_allocatable_pages_set(objspace, size_pool, size_pool->allocatable_pages + freed_pages);
+    }
+
+    heap_pages_free_unused_pages(objspace);
+}
+
 void
 rb_gc_prepare_heap(void)
 {
     rb_objspace_each_objects(gc_set_candidate_object_i, NULL);
     gc_start_internal(NULL, Qtrue, Qtrue, Qtrue, Qtrue, Qtrue);
+    free_empty_pages();
 }
 
 static int
diff --git a/process.c b/process.c
index fa2ae7344a..37dc524415 100644
--- a/process.c
+++ b/process.c
@@ -8671,10 +8671,12 @@ static VALUE rb_mProcID_Syscall;
  *
  *  On CRuby, +Process.warmup+:
  *
- *  * Perform a major GC.
+ *  * Performs a major GC.
  *  * Compacts the heap.
  *  * Promotes all surviving objects to the old generation.
- *  * Precompute the coderange of all strings.
+ *  * Precomputes the coderange of all strings.
+ *  * Frees all empty heap pages and increments the allocatable pages counter
+ *    by the number of pages freed.
  */
 
 static VALUE
diff --git a/test/ruby/test_process.rb b/test/ruby/test_process.rb
index 38dcb8054f..095ab27f5d 100644
--- a/test/ruby/test_process.rb
+++ b/test/ruby/test_process.rb
@@ -2725,4 +2725,26 @@ EOS
       assert_include(ObjectSpace.dump(obj), '"coderange":"7bit"')
     end;
   end
+
+  def test_warmup_frees_pages
+    assert_separately([{"RUBY_GC_HEAP_FREE_SLOTS_MAX_RATIO" => "1.0"}, "-W0"], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      TIMES = 10_000
+      ary = Array.new(TIMES)
+      TIMES.times do |i|
+        ary[i] = Object.new
+      end
+      ary.clear
+      ary = nil
+
+      total_pages_before = GC.stat(:heap_eden_pages) + GC.stat(:heap_allocatable_pages)
+
+      Process.warmup
+
+      # Number of pages freed should cause equal increase in number of allocatable pages.
+      assert_equal(total_pages_before, GC.stat(:heap_eden_pages) + GC.stat(:heap_allocatable_pages))
+      assert_equal(0, GC.stat(:heap_tomb_pages))
+      assert_operator(GC.stat(:total_freed_pages), :>, 0)
+    end;
+  end
 end