memory-infra: add ProcessType and expose data in RequestGlobalDump()

services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom

Index: services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom
diff --git a/services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom b/services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom
index 160ec1241eeac319982f97580c5506eaee780fd4..64ecc12862e1d6069c611039555c8e67a9c1d3d9 100644
--- a/services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom
+++ b/services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom
@@ -10,7 +10,7 @@ enum DumpType {
   PERIODIC_INTERVAL,
   EXPLICITLY_TRIGGERED,
   PEAK_MEMORY_USAGE,
-  SUMMARY_ONLY 
+  SUMMARY_ONLY
 };
 
 enum LevelOfDetail {
@@ -45,25 +45,58 @@ struct ChromeMemDump {
   uint32 v8_total_kb = 0;
 };
 
-struct MemoryDumpCallbackResult {
+enum ProcessType {
+  OTHER,
+  BROWSER,
+  RENDERER,
+  GPU,
+  UTILITY,
+  PLUGIN
+};
+
+// This struct is used both for:
+// 1) The internal communication between the memory service (Coordinator) and
+//    the client library (ProcessLocalDumpManager).
+// 2) The public-facing API Coordinator::RequestGlobalMemoryDump().
+struct ProcessMemoryDump {
+  ProcessType process_type;

[fmeawad, 2017/05/10 17:09:38]

Can we send it as we register instead of sending it with every message?

[Primiano Tucci (use gerrit), 2017/05/10 17:17:19]

the thing is that we want to expose it publicly to our clients, who obtain the
GlobalMemoryDUmp, so that UMA can make grouping based on this.

We could in theory send it only when registering, then keeping this cached on a
map in the coordinator_impl, than copy this back when we generate the
GlobalMemoryDump.Althgouh I am not sure all this is worth the effort of sending
an extra int :)

[fmeawad, 2017/05/10 18:00:16]

Makes sense.

   OSMemDump os_dump;
   ChromeMemDump chrome_dump;
+
+  // TODO(hjd): add the computed Consistent Memory Metrics footprints here.
+
+  // This is used only in the use-case (1) and only on Linux/CrOS to get
+  // around sandboxing. See crbug.com/461788 .
   map<mojo.common.mojom.ProcessId, OSMemDump> extra_processes_dump;
 };
 
-// There should be at most one implementation of this interface per process.
+
+// This struct is returned by the public-facing API
+// Coordinator::RequestGlobalMemoryDump().
+struct GlobalMemoryDump {
+  array<ProcessMemoryDump> process_dumps;
+};
+
+// This is the interface implemented by the client library. This allows a
+// remote process to contribute of the memory-infra dumps. There should be at
+// most one instance of this per hosting process.
 interface ProcessLocalDumpManager {
-  // When successful, the dump is appended in the process-local trace buffer of
-  // the target process and an ACK. A summary of the dump is also returned in
-  // case of success.
+  // When |success| == true the dump is appended in the process-local trace
+  // buffer of the target process and an ACK. A summary of the dump is also
+  // returned in case of success.
   RequestProcessMemoryDump(RequestArgs args) =>
-      (uint64 dump_guid, bool success, MemoryDumpCallbackResult? result);
+      (uint64 dump_guid, bool success, ProcessMemoryDump? process_memory_dump);
 };
 
-// Memory Infra service implements this interface. ProcessLocalDumpManagers
-// register themselves using the RegisterProcessLocalDumpManager method and
-// suggest a global memory dump using the RequestGlobalMemoryDump method.
+// The memory-infra service implements this interface.
 interface Coordinator {
+  // Used to register a client library to obtain a process-local dump from it
+  // when RequestGlobalMemoryDump() is called.
   RegisterProcessLocalDumpManager(ProcessLocalDumpManager local_manager);
-  RequestGlobalMemoryDump(RequestArgs args) => (uint64 dump_guid, bool success);
+
+  // Broadcasts a dump request to all registered client libraries, injects the
+  // dump in the trace buffer (if tracing is enabled) and returns a summarized
+  // dump back if args.dump_type == SUMMARY_ONLY.
+  RequestGlobalMemoryDump(RequestArgs args) =>
+      (uint64 dump_guid, bool success, GlobalMemoryDump? global_memory_dump);
 };