diff --git a/services/substrate/runtime/memory.go b/services/substrate/runtime/memory.go
new file mode 100644
index 00000000..e14e9d18
--- /dev/null
+++ b/services/substrate/runtime/memory.go
@@ -0,0 +1,18 @@
+//go:build linux || darwin
+// +build linux darwin
+
+package runtime
+
+import (
+	"github.com/mackerelio/go-osstat/memory"
+)
+
+func getTotalAndUsedMemory() (totalWithSwap uint64, usedWithSwap uint64, total uint64, used uint64, err error) {
+	mem, err := memory.Get()
+	if err != nil {
+		return 0, 0, 0, 0, err
+	}
+	totalWithSwap = mem.Total + mem.SwapTotal
+	usedWithSwap = mem.Used + mem.SwapUsed
+	return totalWithSwap, usedWithSwap, mem.Total, mem.Used, nil
+}
diff --git a/services/substrate/runtime/memory_windows.go b/services/substrate/runtime/memory_windows.go
new file mode 100644
index 00000000..816f7989
--- /dev/null
+++ b/services/substrate/runtime/memory_windows.go
@@ -0,0 +1,20 @@
+//go:build windows
+// +build windows
+
+package runtime
+
+import (
+	"github.com/mackerelio/go-osstat/memory"
+)
+
+func getTotalAndUsedMemory() (totalWithSwap uint64, usedWithSwap uint64, total uint64, used uint64, err error) {
+	mem, err := memory.Get()
+	if err != nil {
+		return 0, 0, 0, 0, err
+	}
+	totalWithSwap = mem.VirtualTotal
+	usedWithSwap = mem.VirtualTotal - mem.VirtualFree
+	total = mem.Total
+	used = mem.Used
+	return totalWithSwap, usedWithSwap, total, used, nil
+}
diff --git a/services/substrate/runtime/shadow.go b/services/substrate/runtime/shadow.go
index 106dcfa8..7144d38b 100644
--- a/services/substrate/runtime/shadow.go
+++ b/services/substrate/runtime/shadow.go
@@ -6,8 +6,6 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
-
-	"github.com/mackerelio/go-osstat/memory"
 )
 
 var globalInstanceCount int64
@@ -61,14 +59,12 @@ func (f *Function) initShadow() {
 						}
 					}
 
-					mem, err := memory.Get()
+					totalMemAndSwap, usedMemAndSwap, memTotal, memUsed, err := getTotalAndUsedMemory()
 					if err != nil {
 						logger.Errorf("failed to get memory stats: %s", err.Error())
 						continue
 					}
 
-					totalMemAndSwap := mem.Total + mem.SwapTotal
-					usedMemAndSwap := mem.Used + mem.SwapUsed
 					usedMemoryPercentage := (usedMemAndSwap * 100) / totalMemAndSwap
 					if usedMemoryPercentage < MemoryThreshold {
 						maxMemory := f.config.Memory
@@ -76,7 +72,7 @@ func (f *Function) initShadow() {
 							maxMemory = DefaultWasmMemory
 						}
 
-						if mem.Used+maxMemory <= mem.Total {
+						if memUsed+maxMemory <= memTotal {
 							shadow, err := f.shadows.newInstance()
 							if err != nil {
 								logger.Errorf("creating new shadow instance failed with: %s", err.Error())
diff --git a/services/substrate/runtime/utils_test.go b/services/substrate/runtime/utils_for_test.go
similarity index 100%
rename from services/substrate/runtime/utils_test.go
rename to services/substrate/runtime/utils_for_test.go