Merge pull request #2036 from stevvooe/use-buffer-pools

archive, cio, cmd, linux: use buffer pools

cio/io.go

@@ -10,6 +10,13 @@ import (
 	"github.com/containerd/containerd/defaults"
 )
 
+var bufPool = sync.Pool{
+	New: func() interface{} {
+		buffer := make([]byte, 32<<10)
+		return &buffer
+	},
+}
+
 // Config holds the IO configurations.
 type Config struct {
 	// Terminal is true if one has been allocated