diff --git a/package/src/memmon.cpp b/package/src/memmon.cpp
index 07ad006..4b6cc0a 100644
--- a/package/src/memmon.cpp
+++ b/package/src/memmon.cpp
@@ -10,6 +10,7 @@
 #include <iostream>
 #include <limits>
 #include <regex>
+#include <set>
 #include <sstream>
 
 #include "utils.h"
@@ -136,3 +137,44 @@ void const memmon::get_unit_info(nlohmann::json& unit_json) {
   prmon::fill_units(unit_json, params);
   return;
 }
+
+// Toggle on fast memmory monitoring
+void const memmon::do_fastmon() {
+  // Fast monitoring reads the data from a special file
+  // This file is called smaps_rollup instead of smaps
+  input_filename = "smaps_rollup";
+
+  // First discover all available metrics by peeking into self smaps_rollup file
+  std::set<std::string> available_metrics;
+  std::stringstream smaps_fname{"/proc/self/smaps_rollup"};
+  std::ifstream smap_stat{smaps_fname.str()};
+  std::string key_str{}, value_str{};
+  while (smap_stat) {
+    smap_stat >> key_str >> value_str;
+    smap_stat.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
+    if (smap_stat) {
+      if (key_str == "Size:") {
+        available_metrics.insert("vmem");
+      } else if (key_str == "Pss:") {
+        available_metrics.insert("pss");
+      } else if (key_str == "Rss:") {
+        available_metrics.insert("rss");
+      } else if (key_str == "Swap:") {
+        available_metrics.insert("swap");
+      }
+    }
+  }
+
+  // Delete unavailable metrics from the monitored stats
+  // In C++17/20 there are more elegant ways to do this
+  for (auto it = mem_stats.cbegin(); it != mem_stats.cend();) {
+    // Delete unavailable metrics
+    if (available_metrics.count(it->first) == 0) {
+      spdlog::warn("Metric " + it->first +
+                   " is not available in fast monitoring");
+      it = mem_stats.erase(it);
+    } else {
+      it++;
+    }
+  }
+};
diff --git a/package/src/memmon.h b/package/src/memmon.h
index a3618cf..b9fe9ea 100644
--- a/package/src/memmon.h
+++ b/package/src/memmon.h
@@ -53,7 +53,7 @@ class memmon final : public Imonitor, public MessageBase {
   bool const is_valid() { return true; }
 
   // Toggle on fast memmory monitoring
-  inline void const do_fastmon() { input_filename = "smaps_rollup"; };
+  void const do_fastmon();
 };
 REGISTER_MONITOR(Imonitor, memmon, "Monitor memory usage")