[tracing] Display the locked size of discardable memory segment.

content/common/discardable_shared_memory_heap.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/common/discardable_shared_memory_heap.h"
 
 #include <algorithm>
 
 #include "base/format_macros.h"
 #include "base/memory/discardable_shared_memory.h"
@@ skipping 260 matching lines @@
 }
 
 scoped_ptr<DiscardableSharedMemoryHeap::Span>
 DiscardableSharedMemoryHeap::Carve(Span* span, size_t blocks) {
   scoped_ptr<Span> serving = RemoveFromFreeList(span);
 
   const int extra = serving->length_ - blocks;
   if (extra) {
     scoped_ptr<Span> leftover(
         new Span(serving->shared_memory_, serving->start_ + blocks, extra));
+    leftover->set_is_locked(false);
     DCHECK_IMPLIES(extra > 1, spans_.find(leftover->start_) == spans_.end());
     RegisterSpan(leftover.get());
 
     // No need to coalesce as the previous span of |leftover| was just split
     // and the next span of |leftover| was not previously coalesced with
     // |span|.
     InsertIntoFreeList(leftover.Pass());
 
     serving->length_ = blocks;
     spans_[serving->start_ + blocks - 1] = serving.get();
@@ skipping 69 matching lines @@
   }
 }
 
 void DiscardableSharedMemoryHeap::OnMemoryDump(
     const base::DiscardableSharedMemory* shared_memory,
     size_t size,
     int32_t segment_id,
     base::trace_event::ProcessMemoryDump* pmd) {
   size_t allocated_objects_count = 0;
   size_t allocated_objects_size_in_bytes = 0;
+  size_t locked_size_in_bytes = 0;

[reveman, 2015/10/01 10:34:39]

nit: locked_objects_size_in_bytes to be consistent with above variables.

[ssid, 2015/10/01 14:08:46]

Done.

   size_t offset =
       reinterpret_cast<size_t>(shared_memory->memory()) / block_size_;
   size_t end = offset + size / block_size_;
   while (offset < end) {
     Span* span = spans_[offset];
     if (!IsInFreeList(span)) {
+      const size_t span_size = span->length_ * block_size_;

[reveman, 2015/10/01 10:34:39]

How about computing allocated_objects_size_in_blocks and
locked_objects_size_in_blocks and convert to bytes when you call AddScalar
instead multiplying with block_size_ for each iteration? that also removes the
need for this temporary variable.

[ssid, 2015/10/01 14:08:46]

Done.

+      allocated_objects_size_in_bytes += span_size;
+      locked_size_in_bytes += span->is_locked_ ? span_size : 0;
       allocated_objects_count++;
-      allocated_objects_size_in_bytes += span->length_ * block_size_;
     }
     offset += span->length_;
   }
 
   std::string segment_dump_name =
       base::StringPrintf("discardable/segment_%d", segment_id);
   base::trace_event::MemoryAllocatorDump* segment_dump =
       pmd->CreateAllocatorDump(segment_dump_name);
   segment_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                           base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                           static_cast<uint64_t>(size));
 
   base::trace_event::MemoryAllocatorDump* obj_dump =
       pmd->CreateAllocatorDump(segment_dump_name + "/allocated_objects");
   obj_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameObjectCount,
                       base::trace_event::MemoryAllocatorDump::kUnitsObjects,
                       static_cast<uint64_t>(allocated_objects_count));
   obj_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                       base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                       static_cast<uint64_t>(allocated_objects_size_in_bytes));
+  obj_dump->AddScalar("locked_size",
+                      base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                      locked_size_in_bytes);

[reveman, 2015/10/01 10:34:39]

why no static_cast<uint64_t> here but we have one above? either way is fine with
me as long as it's consistent.

[ssid, 2015/10/01 14:08:46]

I think initially it was added since the AddScalar did not accept 64 bit
numbers, that changed now, cleaning up.

 
   // Emit an ownership edge towards a global allocator dump node. This allows
   // to avoid double-counting segments when both browser and child process emit
   // them. In the special case of single-process-mode, this will be the only
   // dumper active and the single ownership edge will become a no-op in the UI.
   const uint64 tracing_process_id =
       base::trace_event::MemoryDumpManager::GetInstance()
           ->GetTracingProcessId();
   base::trace_event::MemoryAllocatorDumpGuid shared_segment_guid =
       GetSegmentGUIDForTracing(tracing_process_id, segment_id);
@@ skipping 29 matching lines @@
   ScopedVector<ScopedMemorySegment>::const_iterator it =
       std::find_if(memory_segments_.begin(), memory_segments_.end(),
                    [span](const ScopedMemorySegment* segment) {
                      return segment->ContainsSpan(span);
                    });
   DCHECK(it != memory_segments_.end());
   return (*it)->CreateMemoryAllocatorDump(span, block_size_, name, pmd);
 }
 
 }  // namespace content