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

tools/ProcStats.h

Index: tools/ProcStats.h
diff --git a/tools/ProcStats.h b/tools/ProcStats.h
index 14b98b7a28c2c187df1d316bf7b628e0286ebdd4..f085fe31a6ff532044928b32a04e567a1be6a5a8 100644
--- a/tools/ProcStats.h
+++ b/tools/ProcStats.h
@@ -15,11 +15,27 @@
 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