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/strings/string_util.h"
  11 #include "base/trace_event/process_memory_dump.h"
  12 #include "base/win/windows_version.h"
  13
  14 namespace base {
  15 namespace trace_event {
  16
  17 #define DUMP_ROOT_NAME "winheap"
  18 // static
  19 const char WinHeapDumpProvider::kAllocatedObjects[] =
  20     DUMP_ROOT_NAME "/allocated_objects";
  21
  22 namespace {
  23
  24 // Report a heap dump to a process memory dump. The |heap_info| structure
  25 // contains the information about this heap, and |dump_absolute_name| will be
  26 // used to represent it in the report.
  27 void ReportHeapDump(ProcessMemoryDump* pmd, const WinHeapInfo& heap_info) {
  28   MemoryAllocatorDump* outer_dump = pmd->CreateAllocatorDump(DUMP_ROOT_NAME);
  29   outer_dump->AddScalar(MemoryAllocatorDump::kNameSize,
  30                         MemoryAllocatorDump::kUnitsBytes,
  31                         heap_info.committed_size);
  32
  33   MemoryAllocatorDump* inner_dump =
  34       pmd->CreateAllocatorDump(WinHeapDumpProvider::kAllocatedObjects);
  35   inner_dump->AddScalar(MemoryAllocatorDump::kNameSize,
  36                         MemoryAllocatorDump::kUnitsBytes,
  37                         heap_info.allocated_size);
  38   inner_dump->AddScalar(MemoryAllocatorDump::kNameObjectsCount,
  39                         MemoryAllocatorDump::kUnitsObjects,
  40                         heap_info.block_count);
  41 }
  42
  43 }  // namespace
  44
  45 WinHeapDumpProvider* WinHeapDumpProvider::GetInstance() {
  46   return Singleton<WinHeapDumpProvider,
  47                    LeakySingletonTraits<WinHeapDumpProvider>>::get();
  48 }
  49
  50 bool WinHeapDumpProvider::OnMemoryDump(ProcessMemoryDump* pmd) {
  51   // This method might be flaky for 2 reasons:
  52   //   - GetProcessHeaps is racy by design. It returns a snapshot of the
  53   //     available heaps, but there's no guarantee that that snapshot remains
  54   //     valid. If a heap disappears between GetProcessHeaps() and HeapWalk()
  55   //     then chaos should be assumed. This flakyness is acceptable for tracing.
  56   //   - The MSDN page for HeapLock says: "If the HeapLock function is called on
  57   //     a heap created with the HEAP_NO_SERIALIZATION flag, the results are
  58   //     undefined.". This is a problem on Windows XP where some system DLLs are
  59   //     known for creating heaps with this particular flag. For this reason
  60   //     this function should be disabled on XP.
  61   //
  62   // See https://crbug.com/487291 for more details about this.
  63   if (base::win::GetVersion() < base::win::VERSION_VISTA)
  64     return false;
  65
  66   // Disable this dump provider for the SyzyASan instrumented build
  67   // because they don't support the heap walking functions yet.
  68 #if defined(SYZYASAN)
  69   if (base::debug::IsBinaryInstrumented())
  70     return false;
  71 #endif
  72
  73   // Retrieves the number of heaps in the current process.
  74   DWORD number_of_heaps = ::GetProcessHeaps(0, NULL);
  75   WinHeapInfo all_heap_info = {0};
  76
  77   // Try to retrieve a handle to all the heaps owned by this process. Returns
  78   // false if the number of heaps has changed.
  79   //
  80   // This is inherently racy as is, but it's not something that we observe a lot
  81   // in Chrome, the heaps tend to be created at startup only.
  82   scoped_ptr<HANDLE[]> all_heaps(new HANDLE[number_of_heaps]);
  83   if (::GetProcessHeaps(number_of_heaps, all_heaps.get()) != number_of_heaps)
  84     return false;
  85
  86   // Skip the pointer to the heap array to avoid accounting the memory used by
  87   // this dump provider.
  88   std::set<void*> block_to_skip;
  89   block_to_skip.insert(all_heaps.get());
  90
  91   // Retrieves some metrics about each heap.
  92   for (size_t i = 0; i < number_of_heaps; ++i) {
  93     WinHeapInfo heap_info = {0};
  94     heap_info.heap_id = all_heaps[i];
  95     GetHeapInformation(&heap_info, block_to_skip);
  96
  97     all_heap_info.allocated_size += heap_info.allocated_size;
  98     all_heap_info.committed_size += heap_info.committed_size;
  99     all_heap_info.block_count += heap_info.block_count;
 100   }
 101   // Report the heap dump.
 102   ReportHeapDump(pmd, all_heap_info);
 103   return true;
 104 }
 105
 106 bool WinHeapDumpProvider::GetHeapInformation(
 107     WinHeapInfo* heap_info,
 108     const std::set<void*>& block_to_skip) {
 109   CHECK(::HeapLock(heap_info->heap_id) == TRUE);
 110   PROCESS_HEAP_ENTRY heap_entry;
 111   heap_entry.lpData = nullptr;
 112   // Walk over all the entries in this heap.
 113   while (::HeapWalk(heap_info->heap_id, &heap_entry) != FALSE) {
 114     if (block_to_skip.count(heap_entry.lpData) == 1)
 115       continue;
 116     if ((heap_entry.wFlags & PROCESS_HEAP_ENTRY_BUSY) != 0) {
 117       heap_info->allocated_size += heap_entry.cbData;
 118       heap_info->block_count++;
 119     } else if ((heap_entry.wFlags & PROCESS_HEAP_REGION) != 0) {
 120       heap_info->committed_size += heap_entry.Region.dwCommittedSize;
 121     }
 122   }
 123   CHECK(::HeapUnlock(heap_info->heap_id) == TRUE);
 124   return true;
 125 }
 126
 127 }  // namespace trace_event
 128 }  // namespace base