base/trace_event/winheap_dump_provider_win.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/trace_event/winheap_dump_provider_win.h"
   6
   7 #include <windows.h>
   8
   9 #include "base/debug/profiler.h"
  10 #include "base/trace_event/process_memory_dump.h"
  11 #include "base/win/windows_version.h"
  12
  13 namespace base {
  14 namespace trace_event {
  15
  16 namespace {
  17
  18 // Report a heap dump to a process memory dump. The |heap_info| structure
  19 // contains the information about this heap, and |dump_absolute_name| will be
  20 // used to represent it in the report.
  21 void ReportHeapDump(ProcessMemoryDump* pmd,
  22                     const WinHeapInfo& heap_info,
  23                     const std::string& dump_absolute_name) {
  24   MemoryAllocatorDump* outer_dump =
  25       pmd->CreateAllocatorDump(dump_absolute_name);
  26   outer_dump->AddScalar(MemoryAllocatorDump::kNameSize,
  27                         MemoryAllocatorDump::kUnitsBytes,
  28                         heap_info.committed_size);
  29
  30   MemoryAllocatorDump* inner_dump =
  31       pmd->CreateAllocatorDump(dump_absolute_name + "/allocated_objects");
  32   inner_dump->AddScalar(MemoryAllocatorDump::kNameSize,
  33                         MemoryAllocatorDump::kUnitsBytes,
  34                         heap_info.allocated_size);
  35   inner_dump->AddScalar(MemoryAllocatorDump::kNameObjectsCount,
  36                         MemoryAllocatorDump::kUnitsObjects,
  37                         heap_info.block_count);
  38 }
  39
  40 }  // namespace
  41
  42 WinHeapDumpProvider* WinHeapDumpProvider::GetInstance() {
  43   return Singleton<WinHeapDumpProvider,
  44                    LeakySingletonTraits<WinHeapDumpProvider>>::get();
  45 }
  46
  47 bool WinHeapDumpProvider::OnMemoryDump(ProcessMemoryDump* pmd) {
  48   // This method might be flaky for 2 reasons:
  49   //   - GetProcessHeaps is racy by design. It returns a snapshot of the
  50   //     available heaps, but there's no guarantee that that snapshot remains
  51   //     valid. If a heap disappears between GetProcessHeaps() and HeapWalk()
  52   //     then chaos should be assumed. This flakyness is acceptable for tracing.
  53   //   - The MSDN page for HeapLock says: "If the HeapLock function is called on
  54   //     a heap created with the HEAP_NO_SERIALIZATION flag, the results are
  55   //     undefined.". This is a problem on Windows XP where some system DLLs are
  56   //     known for creating heaps with this particular flag. For this reason
  57   //     this function should be disabled on XP.
  58   //
  59   // See https://crbug.com/487291 for more details about this.
  60   if (base::win::GetVersion() < base::win::VERSION_VISTA)
  61     return false;
  62
  63   // Disable this dump provider for the SyzyASan instrumented build
  64   // because they don't support the heap walking functions yet.
  65 #if defined(SYZYASAN)
  66   if (base::debug::IsBinaryInstrumented())
  67     return false;
  68 #endif
  69
  70   // Retrieves the number of heaps in the current process.
  71   DWORD number_of_heaps = ::GetProcessHeaps(0, NULL);
  72   WinHeapInfo all_heap_info = {0};
  73
  74   // Try to retrieve a handle to all the heaps owned by this process. Returns
  75   // false if the number of heaps has changed.
  76   //
  77   // This is inherently racy as is, but it's not something that we observe a lot
  78   // in Chrome, the heaps tend to be created at startup only.
  79   scoped_ptr<HANDLE[]> all_heaps(new HANDLE[number_of_heaps]);
  80   if (::GetProcessHeaps(number_of_heaps, all_heaps.get()) != number_of_heaps)
  81     return false;
  82
  83   // Skip the pointer to the heap array to avoid accounting the memory used by
  84   // this dump provider.
  85   std::set<void*> block_to_skip;
  86   block_to_skip.insert(all_heaps.get());
  87
  88   // Retrieves some metrics about each heap.
  89   for (size_t i = 0; i < number_of_heaps; ++i) {
  90     WinHeapInfo heap_info = {0};
  91     heap_info.heap_id = all_heaps[i];
  92     GetHeapInformation(&heap_info, block_to_skip);
  93
  94     all_heap_info.allocated_size += heap_info.allocated_size;
  95     all_heap_info.committed_size += heap_info.committed_size;
  96     all_heap_info.block_count += heap_info.block_count;
  97   }
  98   // Report the heap dump.
  99   ReportHeapDump(pmd, all_heap_info, "winheap");
 100   return true;
 101 }
 102
 103 bool WinHeapDumpProvider::GetHeapInformation(
 104     WinHeapInfo* heap_info,
 105     const std::set<void*>& block_to_skip) {
 106   CHECK(::HeapLock(heap_info->heap_id) == TRUE);
 107   PROCESS_HEAP_ENTRY heap_entry;
 108   heap_entry.lpData = nullptr;
 109   // Walk over all the entries in this heap.
 110   while (::HeapWalk(heap_info->heap_id, &heap_entry) != FALSE) {
 111     if (block_to_skip.count(heap_entry.lpData) == 1)
 112       continue;
 113     if ((heap_entry.wFlags & PROCESS_HEAP_ENTRY_BUSY) != 0) {
 114       heap_info->allocated_size += heap_entry.cbData;
 115       heap_info->block_count++;
 116     } else if ((heap_entry.wFlags & PROCESS_HEAP_REGION) != 0) {
 117       heap_info->committed_size += heap_entry.Region.dwCommittedSize;
 118     }
 119   }
 120   CHECK(::HeapUnlock(heap_info->heap_id) == TRUE);
 121   return true;
 122 }
 123
 124 }  // namespace trace_event
 125 }  // namespace base