--- a/python/mozbuild/mozbuild/controller/building.py
+++ b/python/mozbuild/mozbuild/controller/building.py
@@ -246,20 +246,21 @@ class BuildMonitor(MozbuildObject):
 
         self.warnings_database.prune()
         self.warnings_database.save_to_file(self._warnings_path)
 
         if not record_usage:
             return
 
         try:
-            usage = self.record_resource_usage()
+            usage = self.get_resource_usage()
             if not usage:
                 return
 
+            self.log_resource_usage(usage)
             with open(self._get_state_filename('build_resources.json'), 'w') as fh:
                 json.dump(usage, fh, indent=2)
         except Exception as e:
             self.log(logging.WARNING, 'build_resources_error',
                 {'msg': str(e)},
                 'Exception when writing resource usage file: {msg}')
 
     def _get_finder_cpu_usage(self):
@@ -341,46 +342,33 @@ class BuildMonitor(MozbuildObject):
         excessive = swap_in > 512 * 1048576 or swap_out > 512 * 1048576
         return excessive, swap_in, swap_out
 
     @property
     def have_resource_usage(self):
         """Whether resource usage is available."""
         return self.resources.start_time is not None
 
-    def record_resource_usage(self):
-        """Record the resource usage of this build.
+    def get_resource_usage(self):
+        """ Produce a data structure containing the low-level resource usage information.
 
-        We write a log message containing a high-level summary. We also produce
-        a data structure containing the low-level resource usage information.
         This data structure can e.g. be serialized into JSON and saved for
         subsequent analysis.
 
         If no resource usage is available, None is returned.
         """
         if not self.have_resource_usage:
             return None
 
         cpu_percent = self.resources.aggregate_cpu_percent(phase=None,
             per_cpu=False)
         cpu_times = self.resources.aggregate_cpu_times(phase=None,
             per_cpu=False)
         io = self.resources.aggregate_io(phase=None)
 
-        self._log_resource_usage('Overall system resources', 'resource_usage',
-            self.end_time - self.start_time, cpu_percent, cpu_times, io)
-
-        excessive, sin, sout = self.have_excessive_swapping()
-        if excessive is not None and (sin or sout):
-            sin /= 1048576
-            sout /= 1048576
-            self.log(logging.WARNING, 'swap_activity',
-                {'sin': sin, 'sout': sout},
-                'Swap in/out (MB): {sin}/{sout}')
-
         o = dict(
             version=3,
             argv=sys.argv,
             start=self.start_time,
             end=self.end_time,
             duration=self.end_time - self.start_time,
             resources=[],
             cpu_percent=cpu_percent,
@@ -425,38 +413,45 @@ class BuildMonitor(MozbuildObject):
                 logical_cpu_count=psutil.cpu_count(),
                 physical_cpu_count=psutil.cpu_count(logical=False),
                 swap_total=psutil.swap_memory()[0],
                 vmem_total=psutil.virtual_memory()[0],
             ))
 
         return o
 
-    def _log_resource_usage(self, prefix, m_type, duration, cpu_percent,
-        cpu_times, io, extra_params={}):
+    def log_resource_usage(self, usage):
+        """Summarize the resource usage of this build in a log message."""
+
+        if not usage:
+            return
 
         params = dict(
-            duration=duration,
-            cpu_percent=cpu_percent,
-            io_reads=io.read_count,
-            io_writes=io.write_count,
-            io_read_bytes=io.read_bytes,
-            io_write_bytes=io.write_bytes,
-            io_read_time=io.read_time,
-            io_write_time=io.write_time,
+            duration=self.end_time - self.start_time,
+            cpu_percent=usage['cpu_percent'],
+            io_read_bytes=usage['io'].read_bytes,
+            io_write_bytes=usage['io'].write_bytes,
+            io_read_time=usage['io'].read_time,
+            io_write_time=usage['io'].write_time,
         )
 
-        params.update(extra_params)
-
-        message = prefix + ' - Wall time: {duration:.0f}s; ' \
+        message = 'Overall system resources - Wall time: {duration:.0f}s; ' \
             'CPU: {cpu_percent:.0f}%; ' \
             'Read bytes: {io_read_bytes}; Write bytes: {io_write_bytes}; ' \
             'Read time: {io_read_time}; Write time: {io_write_time}'
 
-        self.log(logging.WARNING, m_type, params, message)
+        self.log(logging.WARNING, 'resource_usage', params, message)
+
+        excessive, sin, sout = self.have_excessive_swapping()
+        if excessive is not None and (sin or sout):
+            sin /= 1048576
+            sout /= 1048576
+            self.log(logging.WARNING, 'swap_activity',
+                {'sin': sin, 'sout': sout},
+                'Swap in/out (MB): {sin}/{sout}')
 
     def ccache_stats(self):
         ccache_stats = None
 
         try:
             ccache = which.which('ccache')
             output = subprocess.check_output([ccache, '-s'])
             ccache_stats = CCacheStats(output)

--- a/python/mozbuild/mozbuild/mach_commands.py
+++ b/python/mozbuild/mozbuild/mach_commands.py
@@ -491,17 +491,17 @@ class Build(MachCommandBase):
             # if excessive:
             #    print(EXCESSIVE_SWAP_MESSAGE)
 
             print('To view resource usage of the build, run |mach '
                 'resource-usage|.')
 
             telemetry_handler = getattr(self._mach_context,
                                         'telemetry_handler', None)
-            telemetry_data = monitor.record_resource_usage()
+            telemetry_data = monitor.get_resource_usage()
 
             # Record build configuration data. For now, we cherry pick
             # items we need rather than grabbing everything, in order
             # to avoid accidentally disclosing PII.
             try:
                 moz_artifact_builds = self.substs.get('MOZ_ARTIFACT_BUILDS',
                                                       False)
                 telemetry_data['substs'] = {