DM: display current memory usage (instead of peak) when available.

tools/ProcStats.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef ProcStats_DEFINED
 #define ProcStats_DEFINED
 
 /**
  * ProcStats - Process Statistics Functions
  */
 
 namespace sk_tools {
 
 /**
- *  If not implemented for this OS, returns -1.  Otherwise, return
- *  the maximum resident set size, as reported by getrusage().
+ *  If implemented, returns the maximum resident set size in MB.
+ *  If not, returns -1.
  */
 int getMaxResidentSetSizeMB();
 
+/**
+ *  If implemented, returns the current resident set size in MB.
+ *  If not, returns -1.
+ */
+int getCurrResidentSetSizeMB();
+
+/**
+ *  If implemented, returns getCurrResidentSetSizeMB().
+ *  If not, if implemented, returns getMaxResidentSetSizeMB().
+ *  If not, returns -1.
+ */
+inline int getBestResidentSetSizeMB() {
+    int mb = getCurrResidentSetSizeMB();
+    return mb >= 0 ? mb : getMaxResidentSetSizeMB();
+}
+
 }  // namespace sk_tools
 
 #endif  // ProcStats_DEFINED