diff --git a/base/interactiveutil.jl b/base/interactiveutil.jl
index 8ce74ff203dd6..876d123d14483 100644
--- a/base/interactiveutil.jl
+++ b/base/interactiveutil.jl
@@ -716,151 +716,3 @@ function whos(io::IO=STDOUT, m::Module=current_module(), pattern::Regex=r"")
 end
 whos(m::Module, pat::Regex=r"") = whos(STDOUT, m, pat)
 whos(pat::Regex) = whos(STDOUT, current_module(), pat)
-
-#################################################################################
-
-"""
-    Base.summarysize(obj; exclude=Union{Module,DataType,TypeName}) -> Int
-
-Compute the amount of memory used by all unique objects reachable from the argument.
-Keyword argument `exclude` specifies a type of objects to exclude from the traversal.
-"""
-summarysize(obj; exclude = Union{Module,DataType,TypeName}) =
-    summarysize(obj, ObjectIdDict(), exclude)
-
-summarysize(obj::Symbol, seen, excl) = 0
-
-function summarysize(obj::UnionAll, seen, excl)
-    return 2*sizeof(Int) + summarysize(obj.body, seen, excl) + summarysize(obj.var, seen, excl)
-end
-
-function summarysize(obj::DataType, seen, excl)
-    key = pointer_from_objref(obj)
-    haskey(seen, key) ? (return 0) : (seen[key] = true)
-    size = 7*sizeof(Int) + 6*sizeof(Int32) + 4*nfields(obj) + ifelse(Sys.WORD_SIZE == 64, 4, 0)
-    size += summarysize(obj.parameters, seen, excl)::Int
-    size += summarysize(obj.types, seen, excl)::Int
-    return size
-end
-
-function summarysize(obj::TypeName, seen, excl)
-    key = pointer_from_objref(obj)
-    haskey(seen, key) ? (return 0) : (seen[key] = true)
-    return Core.sizeof(obj) + (isdefined(obj,:mt) ? summarysize(obj.mt, seen, excl) : 0)
-end
-
-summarysize(obj::ANY, seen, excl) = _summarysize(obj, seen, excl)
-# define the general case separately to make sure it is not specialized for every type
-function _summarysize(obj::ANY, seen, excl)
-    key = pointer_from_objref(obj)
-    haskey(seen, key) ? (return 0) : (seen[key] = true)
-    size = Core.sizeof(obj)
-    ft = typeof(obj).types
-    for i in 1:nfields(obj)
-        if !isbits(ft[i]) && isdefined(obj,i)
-            val = getfield(obj, i)
-            if !isa(val,excl)
-                size += summarysize(val, seen, excl)::Int
-            end
-        end
-    end
-    return size
-end
-
-function summarysize(obj::Array, seen, excl)
-    haskey(seen, obj) ? (return 0) : (seen[obj] = true)
-    size = Core.sizeof(obj)
-    # TODO: add size of jl_array_t
-    if !isbits(eltype(obj))
-        for i in 1:length(obj)
-            if ccall(:jl_array_isassigned, Cint, (Any, UInt), obj, i-1) == 1
-                val = obj[i]
-                if !isa(val, excl)
-                    size += summarysize(val, seen, excl)::Int
-                end
-            end
-        end
-    end
-    return size
-end
-
-summarysize(s::String, seen, excl) = sizeof(Int) + sizeof(s)
-
-function summarysize(obj::SimpleVector, seen, excl)
-    key = pointer_from_objref(obj)
-    haskey(seen, key) ? (return 0) : (seen[key] = true)
-    size = Core.sizeof(obj)
-    for i in 1:length(obj)
-        if isassigned(obj, i)
-            val = obj[i]
-            if !isa(val, excl)
-                size += summarysize(val, seen, excl)::Int
-            end
-        end
-    end
-    return size
-end
-
-function summarysize(obj::Module, seen, excl)
-    haskey(seen, obj) ? (return 0) : (seen[obj] = true)
-    size::Int = Core.sizeof(obj)
-    for binding in names(obj, true)
-        if isdefined(obj, binding) && !isdeprecated(obj, binding)
-            value = getfield(obj, binding)
-            if !isa(value, Module) || module_parent(value) === obj
-                size += summarysize(value, seen, excl)::Int
-                vt = isa(value,DataType) ? value : typeof(value)
-                if vt.name.module === obj
-                    if vt !== value
-                        size += summarysize(vt, seen, excl)::Int
-                    end
-                    # charge a TypeName to its module
-                    size += summarysize(vt.name, seen, excl)::Int
-                end
-            end
-        end
-    end
-    return size
-end
-
-function summarysize(obj::Task, seen, excl)
-    haskey(seen, obj) ? (return 0) : (seen[obj] = true)
-    size::Int = Core.sizeof(obj)
-    if isdefined(obj, :code)
-        size += summarysize(obj.code, seen, excl)::Int
-    end
-    size += summarysize(obj.storage, seen, excl)::Int
-    size += summarysize(obj.backtrace, seen, excl)::Int
-    size += summarysize(obj.donenotify, seen, excl)::Int
-    size += summarysize(obj.exception, seen, excl)::Int
-    size += summarysize(obj.result, seen, excl)::Int
-    # TODO: add stack size, and possibly traverse stack roots
-    return size
-end
-
-function summarysize(obj::MethodTable, seen, excl)
-    haskey(seen, obj) ? (return 0) : (seen[obj] = true)
-    size::Int = Core.sizeof(obj)
-    size += summarysize(obj.defs, seen, excl)::Int
-    size += summarysize(obj.cache, seen, excl)::Int
-    if isdefined(obj, :kwsorter)
-        size += summarysize(obj.kwsorter, seen, excl)::Int
-    end
-    return size
-end
-
-function summarysize(m::TypeMapEntry, seen, excl)
-    size::Int = 0
-    while true # specialized to prevent stack overflow while following this linked list
-        haskey(seen, m) ? (return size) : (seen[m] = true)
-        size += Core.sizeof(m)
-        if isdefined(m, :func)
-            size += summarysize(m.func, seen, excl)::Int
-        end
-        size += summarysize(m.sig, seen, excl)::Int
-        size += summarysize(m.tvars, seen, excl)::Int
-        m.next === nothing && break
-        m = m.next::TypeMapEntry
-    end
-    return size
-end
diff --git a/base/summarysize.jl b/base/summarysize.jl
new file mode 100644
index 0000000000000..25b7679795e48
--- /dev/null
+++ b/base/summarysize.jl
@@ -0,0 +1,153 @@
+immutable SummarySize
+    seen::ObjectIdDict
+    frontier_x::Vector{Any}
+    frontier_i::Vector{Int}
+    exclude::Any
+    chargeall::Any
+end
+
+
+"""
+    Base.summarysize(obj; exclude=Union{...}, chargeall=Union{...}) -> Int
+
+Compute the amount of memory used by all unique objects reachable from the argument.
+
+# Keyword Arguments
+* `exclude`: specifies the types of objects to exclude from the traversal.
+* `chargeall`: specifies the types of objects to always charge the size of all of their fields,
+               even if those fields would normally be excluded.
+"""
+function summarysize(obj::ANY;
+                     exclude::ANY = Union{DataType, TypeName, Method},
+                     chargeall::ANY = Union{TypeMapEntry, Core.MethodInstance})
+    ss = SummarySize(ObjectIdDict(), Any[], Int[], exclude, chargeall)
+    size::Int = ss(obj)
+    while !isempty(ss.frontier_x)
+        # DFS heap traversal of everything without a specialization
+        # BFS heap traversal of anything with a specialization
+        x = ss.frontier_x[end]
+        i = ss.frontier_i[end]
+        val = nothing
+        if isa(x, SimpleVector)
+            nf = length(x)
+            if isassigned(x, i)
+                val = x[i]
+            end
+        elseif isa(x, Array)
+            nf = length(x)
+            if ccall(:jl_array_isassigned, Cint, (Any, UInt), x, i - 1) != 0
+                val = x[i]
+            end
+        else
+            nf = nfields(x)
+            ft = typeof(x).types
+            if !isbits(ft[i]) && isdefined(x, i)
+                val = getfield(x, i)
+            end
+        end
+        if nf > i
+            ss.frontier_i[end] = i + 1
+        else
+            pop!(ss.frontier_x)
+            pop!(ss.frontier_i)
+        end
+        if val !== nothing && !isa(val, Module) && (!isa(val, ss.exclude) || isa(x, ss.chargeall))
+            size += ss(val)::Int
+        end
+    end
+    return size
+end
+
+(ss::SummarySize)(obj::ANY) = _summarysize(ss, obj)
+# define the general case separately to make sure it is not specialized for every type
+@noinline function _summarysize(ss::SummarySize, obj::ANY)
+    key = pointer_from_objref(obj)
+    haskey(ss.seen, key) ? (return 0) : (ss.seen[key] = true)
+    if nfields(obj) > 0
+        push!(ss.frontier_x, obj)
+        push!(ss.frontier_i, 1)
+    end
+    if isa(obj, UnionAll)
+        # black-list of items that don't have a Core.sizeof
+        return 2 * sizeof(Int)
+    end
+    return Core.sizeof(obj)
+end
+
+(::SummarySize)(obj::Symbol) = 0
+(::SummarySize)(obj::SummarySize) = 0
+(::SummarySize)(obj::String) = Core.sizeof(Int) + Core.sizeof(obj)
+
+function (ss::SummarySize)(obj::DataType)
+    key = pointer_from_objref(obj)
+    haskey(ss.seen, key) ? (return 0) : (ss.seen[key] = true)
+    size::Int = 7 * Core.sizeof(Int) + 6 * Core.sizeof(Int32)
+    size += 4 * nfields(obj) + ifelse(Sys.WORD_SIZE == 64, 4, 0)
+    size += ss(obj.parameters)::Int
+    size += ss(obj.types)::Int
+    return size
+end
+
+function (ss::SummarySize)(obj::TypeName)
+    key = pointer_from_objref(obj)
+    haskey(ss.seen, key) ? (return 0) : (ss.seen[key] = true)
+    return Core.sizeof(obj) + (isdefined(obj, :mt) ? ss(obj.mt) : 0)
+end
+
+function (ss::SummarySize)(obj::Array)
+    haskey(ss.seen, obj) ? (return 0) : (ss.seen[obj] = true)
+    size::Int = Core.sizeof(obj)
+    # TODO: add size of jl_array_t
+    if !isbits(eltype(obj)) && !isempty(obj)
+        push!(ss.frontier_x, obj)
+        push!(ss.frontier_i, 1)
+    end
+    return size
+end
+
+function (ss::SummarySize)(obj::SimpleVector)
+    key = pointer_from_objref(obj)
+    haskey(ss.seen, key) ? (return 0) : (ss.seen[key] = true)
+    size::Int = Core.sizeof(obj)
+    if !isempty(obj)
+        push!(ss.frontier_x, obj)
+        push!(ss.frontier_i, 1)
+    end
+    return size
+end
+
+function (ss::SummarySize)(obj::Module)
+    haskey(ss.seen, obj) ? (return 0) : (ss.seen[obj] = true)
+    size::Int = Core.sizeof(obj)
+    for binding in names(obj, true)
+        if isdefined(obj, binding) && !isdeprecated(obj, binding)
+            value = getfield(obj, binding)
+            if !isa(value, Module) || module_parent(value) === obj
+                size += ss(value)::Int
+                if isa(value, UnionAll)
+                    value = unwrap_unionall(value)
+                end
+                if isa(value, DataType) && value.name.module === obj && value.name.name === binding
+                    # charge a TypeName to its module (but not to the type)
+                    size += ss(value.name)::Int
+                end
+            end
+        end
+    end
+    return size
+end
+
+function (ss::SummarySize)(obj::Task)
+    haskey(ss.seen, obj) ? (return 0) : (ss.seen[obj] = true)
+    size::Int = Core.sizeof(obj)
+    if isdefined(obj, :code)
+        size += ss(obj.code)::Int
+    end
+    size += ss(obj.storage)::Int
+    size += ss(obj.backtrace)::Int
+    size += ss(obj.donenotify)::Int
+    size += ss(obj.exception)::Int
+    size += ss(obj.result)::Int
+    # TODO: add stack size, and possibly traverse stack roots
+    return size
+end
diff --git a/base/sysimg.jl b/base/sysimg.jl
index d4035fcc410d3..8fa9991f8daa5 100644
--- a/base/sysimg.jl
+++ b/base/sysimg.jl
@@ -300,6 +300,7 @@ include("datafmt.jl")
 importall .DataFmt
 include("deepcopy.jl")
 include("interactiveutil.jl")
+include("summarysize.jl")
 include("replutil.jl")
 include("test.jl")
 include("i18n.jl")
diff --git a/test/misc.jl b/test/misc.jl
index af9972d1f8210..c5fa181ace766 100644
--- a/test/misc.jl
+++ b/test/misc.jl
@@ -293,8 +293,17 @@ v11801, t11801 = @timed sin(1)
 # interactive utilities
 
 import Base.summarysize
-@test summarysize(Core) > summarysize(Core.Inference) > Core.sizeof(Core)
-@test summarysize(Base) > 10_000*sizeof(Int)
+@test summarysize(Core) > (summarysize(Core.Inference) + Base.summarysize(Core.Intrinsics)) > Core.sizeof(Core)
+@test summarysize(Base) > 100_000 * sizeof(Ptr)
+
+let R = Ref{Any}(nothing), depth = 10^6
+    for i = 1:depth
+        R = Ref{Any}(R)
+    end
+    R = Core.svec(R, R)
+    @test summarysize(R) == (depth + 4) * sizeof(Ptr)
+end
+
 module _test_whos_
 export x
 x = 1.0