More memory profiling

spec/memprof.rb

@@ -0,0 +1,37 @@
+require 'objspace'
+
+module MemoryUsage
+  MemoryReport = Struct.new(:total_memsize)
+
+  def self.full_gc
+    GC.start(full_mark: true)
+  end
+
+  def self.report(&block)
+    rvalue_size = GC::INTERNAL_CONSTANTS[:RVALUE_SIZE]
+
+    full_gc
+    GC.disable
+
+    total_memsize = 0
+
+    generation = nil
+    ObjectSpace.trace_object_allocations do
+      generation = GC.count
+      block.call
+    end
+
+    ObjectSpace.each_object do |obj|
+      next unless generation == ObjectSpace.allocation_generation(obj)
+      memsize = ObjectSpace.memsize_of(obj) + rvalue_size
+      # compensate for API bug
+      memsize = rvalue_size if memsize > 100_000_000_000
+      total_memsize += memsize
+    end
+
+    GC.enable
+    full_gc
+
+    return MemoryReport.new(total_memsize)
+  end
+end