Add Web Resources usage to chrome://tracing.

third_party/WebKit/Source/platform/PurgeableVector.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "platform/PurgeableVector.h"
 
 #include "public/platform/Platform.h"
 #include "public/platform/WebDiscardableMemory.h"
+#include "public/platform/WebProcessMemoryDump.h"
 #include "wtf/Assertions.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
 
 #include <cstring>
 
 namespace blink {
 
 // WebDiscardableMemory allocations are expensive and page-grained. We only use
 // them when there's a reasonable amount of memory to be saved by the OS
@@ skipping 26 matching lines @@
         // Using reserveInitialCapacity() on the underlying vector ensures that the vector uses the
         // exact specified capacity to avoid consuming too much memory for small resources.
         m_vector.reserveInitialCapacity(capacity);
     } else {
         m_vector.reserveCapacity(capacity);
     }
 
     moveDataFromDiscardableToVector();
 }
 
+void PurgeableVector::onMemoryDump(const String& dumpName, WebProcessMemoryDump* memoryDump) const
+{
+    WebMemoryAllocatorDump* dump = memoryDump->createDiscardableMemoryAllocatorDump(dumpName, m_discardable.get());
+    if (m_discardable) {
+        dump->AddScalar("discardable_size", "bytes", m_discardableSize);

[haraken, 2015/09/28 14:54:02]

This is confusing. Even if m_discardable is non-null, it is not discardable
while m_discardable.isLocked() returns true. I think this should be:

  if (m_discardable) {
    if (m_discardable.isLocked())
      ...;
    else
      ...;
  } else {
    ...;
  }

[ssid, 2015/09/28 16:24:38]

I am sorry I screwed up the condition here. Now fixed it.

Now it just dumps both, not thinking if locked or not.
It means: if discardable it creates a discardable dump,
and it creates a normal dump with sub-allocations from partition alloc.
This createDiscardableMemoryAllocatorDump is added in the cl
http://crrev.com/1372573003.

Do you think this is fine?

+    } else if (m_vector.size() > 0) {
+        dump->AddScalar("size", "bytes", m_vector.size());
+        memoryDump->AddSuballocation(dump->guid(), String(WTF::Partitions::allocatorPoolNameForTracing()));

[haraken, 2015/09/28 14:54:02]

What does allocatorPoolNameForTracing return? (I couldn't find it in a code
search.)

[ssid, 2015/09/28 16:24:38]

Sorry, this is added in this CL https://codereview.chromium.org/1366203002/.
Just returns "partition_alloc/allocated_objects" meaning this is allocated from
partitionAlloc.

+    }
+}
+
 void PurgeableVector::moveDataFromDiscardableToVector()
 {
     if (m_discardable) {
         m_vector.append(static_cast<const char*>(m_discardable->data()), m_discardableSize);
         clearDiscardable();
     }
 }
 
 void PurgeableVector::clearDiscardable()
 {
@@ skipping 161 matching lines @@
     // fragmentation.
     // Since the page size is only used below to minimize fragmentation it's still safe to use it
     // even if it gets out of sync (e.g. due to the use of huge pages).
     const size_t kPageSize = 4096;
     newCapacity = (newCapacity + kPageSize - 1) & ~(kPageSize - 1);
 
     return std::max(capacity, newCapacity); // Overflow check.
 }
 
 } // namespace blink