Instrument SSL sockets using MemoryDumpProvider

net/http/http_network_session.cc

Index: net/http/http_network_session.cc
diff --git a/net/http/http_network_session.cc b/net/http/http_network_session.cc
index cbe28807c501264b4112e13a86b7a87155f5ce9f..3099291ca9e6e9bccddc665d8553fa830aaae708 100644
--- a/net/http/http_network_session.cc
+++ b/net/http/http_network_session.cc
@@ -15,6 +15,9 @@
 #include "base/profiler/scoped_tracker.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "base/trace_event/memory_allocator_dump.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "base/values.h"
 #include "net/base/network_throttle_manager_impl.h"
 #include "net/http/http_auth_handler_factory.h"
@@ -377,6 +380,29 @@ void HttpNetworkSession::GetSSLConfig(const HttpRequestInfo& request,
   }
 }
 
+void HttpNetworkSession::DumpMemoryStats(
+    base::trace_event::ProcessMemoryDump* pmd,
+    const std::string& parent_absolute_name) const {
+  std::string name = base::StringPrintf("net/http_network_session_%p", this);
+  base::trace_event::MemoryAllocatorDump* http_network_session_dump =
+      pmd->GetAllocatorDump(name);
+  // If memory dump already exists, it means that this is not the first
+  // DumpMemoryStats() invocation on this object and it is reached by another
+  // "parent." If that's the case, add an ownership edge and return early.
+  // This is needed because URLRequestContexts can share an HttpNetworkSession.
+  if (http_network_session_dump != nullptr) {
+    pmd->AddOwnershipEdge(pmd->GetAllocatorDump(parent_absolute_name)->guid(),

[Primiano Tucci (use gerrit), 2016/12/06 17:06:28]

Hmm I think this is not going to make anything useful (if not hit a DCHECK).
What is the intented result of this?

The part where you check if network_session_X exists and early out is okay. But
creating two edges between the same nodes doesn't make lot of sense.

[xunjieli, 2016/12/06 18:36:08]

No, it won't ever create two edges between the same nodes.

Say we have context1 and context2, which share a http_network_session.
context1->OnMemoryDump() calls http_network_session::DumpMemoryStats() and adds
an edge between context1 and http_network_session.
context2->OnMemoryDump() will add an edge between context2 and
http_network_session.

[Primiano Tucci (use gerrit), 2016/12/06 20:15:41]

We had an offline chat on this. I dumped my brain on
https://docs.google.com/document/d/1-dmr_dVgO090Y5_3K9itjsE0MsBTmbqwovu6lup1i...

The rest of this CL makes sense to me, and I think we are aligned on two
possible options here.
My suggestion is to go ahead and land this regardless of this conversation (%
net owners being okay with the rest of the code) in order to avoid a cross
timezone round-trip-time.
Even in the worst case this is the kind of thing that can be fixed quite easily
in a follow-up.
So speculatively LGTM from the memory-reporting viewpoint.

Thanks a lot for working on this, It's quite conceptually challenging (also fun)
:)

[xunjieli, 2016/12/06 21:22:11]

Thanks for the follow-up! I tried your suggestion (Option #2), but I don't think
the UI gives what we want. I will keep this as it is and continue this
discussion via email.

+                          http_network_session_dump->guid());
+
+    return;
+  }
+  http_network_session_dump = pmd->CreateAllocatorDump(name);
+  normal_socket_pool_manager_->DumpMemoryStats(
+      pmd, http_network_session_dump->absolute_name());
+  pmd->AddOwnershipEdge(pmd->GetAllocatorDump(parent_absolute_name)->guid(),
+                        http_network_session_dump->guid());
+}
+
 ClientSocketPoolManager* HttpNetworkSession::GetSocketPoolManager(
     SocketPoolType pool_type) {
   switch (pool_type) {