[tracing] Dump child processes' memory metrics in browser

components/tracing/process_metrics_memory_dump_provider.cc

Index: components/tracing/process_metrics_memory_dump_provider.cc
diff --git a/components/tracing/process_metrics_memory_dump_provider.cc b/components/tracing/process_metrics_memory_dump_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e73ea78711dc4818e86d3926899fd23bf82a3fc1
--- /dev/null
+++ b/components/tracing/process_metrics_memory_dump_provider.cc
@@ -0,0 +1,305 @@
+// Copyright 2015 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 "components/tracing/process_metrics_memory_dump_provider.h"
+
+#include <fcntl.h>
+#include <stdint.h>
+
+#include <map>
+
+#include "base/files/file_util.h"
+#include "base/files/scoped_file.h"
+#include "base/format_macros.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/process/process_metrics.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/process_memory_maps.h"
+#include "base/trace_event/process_memory_totals.h"
+#include "build/build_config.h"
+
+namespace tracing {
+
+namespace {
+
+base::LazyInstance<
+    std::map<base::ProcessId, scoped_ptr<ProcessMetricsMemoryDumpProvider>>>::
+    Leaky g_dump_providers_map = LAZY_INSTANCE_INITIALIZER;
+
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+const char kClearPeakRssCommand[] = "5";
+
+const uint32_t kMaxLineSize = 4096;
+
+bool ParseSmapsHeader(const char* header_line,
+                      base::trace_event::ProcessMemoryMaps::VMRegion* region) {
+  // e.g., "00400000-00421000 r-xp 00000000 fc:01 1234  /foo.so\n"
+  bool res = true;  // Whether this region should be appended or skipped.
+  uint64_t end_addr = 0;
+  char protection_flags[5] = {0};
+  char mapped_file[kMaxLineSize];
+
+  if (sscanf(header_line, "%" SCNx64 "-%" SCNx64 " %4c %*s %*s %*s%4095[^\n]\n",
+             &region->start_address, &end_addr, protection_flags,
+             mapped_file) != 4)
+    return false;
+
+  if (end_addr > region->start_address) {
+    region->size_in_bytes = end_addr - region->start_address;
+  } else {
+    // This is not just paranoia, it can actually happen (See crbug.com/461237).
+    region->size_in_bytes = 0;
+    res = false;
+  }
+
+  region->protection_flags = 0;
+  if (protection_flags[0] == 'r') {
+    region->protection_flags |=
+        base::trace_event::ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
+  }
+  if (protection_flags[1] == 'w') {
+    region->protection_flags |=
+        base::trace_event::ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
+  }
+  if (protection_flags[2] == 'x') {
+    region->protection_flags |=
+        base::trace_event::ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
+  }
+
+  region->mapped_file = mapped_file;
+  base::TrimWhitespaceASCII(region->mapped_file, base::TRIM_ALL,
+                            &region->mapped_file);
+
+  return res;
+}
+
+uint64_t ReadCounterBytes(char* counter_line) {
+  uint64_t counter_value = 0;
+  int res = sscanf(counter_line, "%*s %" SCNu64 " kB", &counter_value);
+  return res == 1 ? counter_value * 1024 : 0;
+}
+
+uint32_t ParseSmapsCounter(
+    char* counter_line,
+    base::trace_event::ProcessMemoryMaps::VMRegion* region) {
+  // A smaps counter lines looks as follows: "RSS:  0 Kb\n"
+  uint32_t res = 1;
+  char counter_name[20];
+  int did_read = sscanf(counter_line, "%19[^\n ]", counter_name);
+  if (did_read != 1)
+    return 0;
+
+  if (strcmp(counter_name, "Pss:") == 0) {
+    region->byte_stats_proportional_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Private_Dirty:") == 0) {
+    region->byte_stats_private_dirty_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Private_Clean:") == 0) {
+    region->byte_stats_private_clean_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Shared_Dirty:") == 0) {
+    region->byte_stats_shared_dirty_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Shared_Clean:") == 0) {
+    region->byte_stats_shared_clean_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Swap:") == 0) {
+    region->byte_stats_swapped = ReadCounterBytes(counter_line);
+  } else {
+    res = 0;
+  }
+
+  return res;
+}
+
+uint32_t ReadLinuxProcSmapsFile(FILE* smaps_file,
+                                base::trace_event::ProcessMemoryMaps* pmm) {
+  if (!smaps_file)
+    return 0;
+
+  fseek(smaps_file, 0, SEEK_SET);
+
+  char line[kMaxLineSize];
+  const uint32_t kNumExpectedCountersPerRegion = 6;
+  uint32_t counters_parsed_for_current_region = 0;
+  uint32_t num_valid_regions = 0;
+  base::trace_event::ProcessMemoryMaps::VMRegion region;
+  bool should_add_current_region = false;
+  for (;;) {
+    line[0] = '\0';
+    if (fgets(line, kMaxLineSize, smaps_file) == nullptr || !strlen(line))
+      break;
+    if (isxdigit(line[0]) && !isupper(line[0])) {
+      region = base::trace_event::ProcessMemoryMaps::VMRegion();
+      counters_parsed_for_current_region = 0;
+      should_add_current_region = ParseSmapsHeader(line, &region);
+    } else {
+      counters_parsed_for_current_region += ParseSmapsCounter(line, &region);
+      DCHECK_LE(counters_parsed_for_current_region,
+                kNumExpectedCountersPerRegion);
+      if (counters_parsed_for_current_region == kNumExpectedCountersPerRegion) {
+        if (should_add_current_region) {
+          pmm->AddVMRegion(region);
+          ++num_valid_regions;
+          should_add_current_region = false;
+        }
+      }
+    }
+  }
+  return num_valid_regions;
+}
+#endif  // defined(OS_LINUX) || defined(OS_ANDROID)
+
+scoped_ptr<base::ProcessMetrics> CreateProcessMetrics(base::ProcessId process) {
+  if (process == base::kNullProcessId)
+    return make_scoped_ptr(base::ProcessMetrics::CreateCurrentProcessMetrics());
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  // Just pass ProcessId instead of handle since they are the same in linux and
+  // android.
+  return make_scoped_ptr(base::ProcessMetrics::CreateProcessMetrics(process));
+#else
+  // Creating process metrics for child processes in mac or windows requires
+  // additional information like ProcessHandle or port provider. This is a non
+  // needed use case.
+  NOTREACHED();
+  return scoped_ptr<base::ProcessMetrics>();
+#endif  // defined(OS_LINUX) || defined(OS_ANDROID)
+}
+
+}  // namespace
+
+// static
+uint64_t ProcessMetricsMemoryDumpProvider::rss_bytes_for_testing = 0;
+
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+
+// static
+FILE* ProcessMetricsMemoryDumpProvider::proc_smaps_for_testing = nullptr;
+
+bool ProcessMetricsMemoryDumpProvider::DumpProcessMemoryMaps(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  uint32_t res = 0;
+  if (proc_smaps_for_testing) {
+    res = ReadLinuxProcSmapsFile(proc_smaps_for_testing, pmd->process_mmaps());
+  } else {
+    std::string file_name = "/proc/" + (process_ == base::kNullProcessId
+                                            ? "self"
+                                            : base::IntToString(process_)) +
+                            "/smaps";
+    base::ScopedFILE smaps_file(fopen(file_name.c_str(), "r"));
+    res = ReadLinuxProcSmapsFile(smaps_file.get(), pmd->process_mmaps());
+  }
+
+  if (res)
+    pmd->set_has_process_mmaps();
+  return res;
+}
+#endif  // defined(OS_LINUX) || defined(OS_ANDROID)
+
+// static
+void ProcessMetricsMemoryDumpProvider::RegisterForProcess(
+    base::ProcessId process) {
+  scoped_ptr<ProcessMetricsMemoryDumpProvider> metrics_provider(
+      new ProcessMetricsMemoryDumpProvider(process));
+  base::trace_event::MemoryDumpProvider::Options options(process);
+  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
+      metrics_provider.get(), "ProcessMemoryMetrics", nullptr, options);
+  bool did_insert =
+      g_dump_providers_map.Get()
+          .insert(std::make_pair(process, std::move(metrics_provider)))
+          .second;
+  if (!did_insert) {
+    DLOG(ERROR) << "ProcessMetricsMemoryDumpProvider already registered for "
+                << (process == base::kNullProcessId
+                        ? "current process"
+                        : "process id " + base::IntToString(process));
+  }
+}
+
+// static
+void ProcessMetricsMemoryDumpProvider::UnregisterForProcess(
+    base::ProcessId process) {
+  auto iter = g_dump_providers_map.Get().find(process);
+  if (iter == g_dump_providers_map.Get().end()) {
+    return;
+  }
+  base::trace_event::MemoryDumpManager::GetInstance()
+      ->UnregisterAndDeleteDumpProviderSoon(std::move(iter->second));
+  g_dump_providers_map.Get().erase(iter);
+}
+
+ProcessMetricsMemoryDumpProvider::ProcessMetricsMemoryDumpProvider(
+    base::ProcessId process)
+    : process_(process),
+      process_metrics_(CreateProcessMetrics(process)),
+      is_rss_peak_resettable_(true) {}
+
+ProcessMetricsMemoryDumpProvider::~ProcessMetricsMemoryDumpProvider() {}
+
+// Called at trace dump point time. Creates a snapshot of the memory maps for
+// the current process.
+bool ProcessMetricsMemoryDumpProvider::OnMemoryDump(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  bool res = DumpProcessTotals(args, pmd);
+
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  if (args.level_of_detail ==
+      base::trace_event::MemoryDumpLevelOfDetail::DETAILED)
+    res &= DumpProcessMemoryMaps(args, pmd);
+#endif
+  return res;
+}
+
+bool ProcessMetricsMemoryDumpProvider::DumpProcessTotals(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  const uint64_t rss_bytes = rss_bytes_for_testing
+                                 ? rss_bytes_for_testing
+                                 : process_metrics_->GetWorkingSetSize();
+
+  // rss_bytes will be 0 if the process ended while dumping.
+  if (!rss_bytes)
+    return false;
+
+  uint64_t peak_rss_bytes = 0;
+
+#if !defined(OS_IOS)
+  peak_rss_bytes = process_metrics_->GetPeakWorkingSetSize();
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  if (is_rss_peak_resettable_) {
+    std::string clear_refs_file =
+        "/proc/" +
+        (process_ == base::kNullProcessId ? "self"
+                                          : base::IntToString(process_)) +
+        "/clear_refs";
+    int clear_refs_fd = open(clear_refs_file.c_str(), O_WRONLY);
+    if (clear_refs_fd > 0 &&
+        base::WriteFileDescriptor(clear_refs_fd, kClearPeakRssCommand,
+                                  sizeof(kClearPeakRssCommand))) {
+      pmd->process_totals()->set_is_peak_rss_resetable(true);
+    } else {
+      is_rss_peak_resettable_ = false;
+    }
+    close(clear_refs_fd);
+  }
+#elif defined(MACOSX)
+  size_t private_bytes;
+  bool res = process_metrics_->GetMemoryBytes(&private_bytes,
+                                              nullptr /* shared_bytes */);
+  if (res)
+    pmd->process_totals()->SetExtraFieldInBytes("private_bytes", private_bytes);
+#endif  // defined(OS_LINUX) || defined(OS_ANDROID)
+#endif  // !defined(OS_IOS)
+
+  pmd->process_totals()->set_resident_set_bytes(rss_bytes);
+  pmd->set_has_process_totals();
+  pmd->process_totals()->set_peak_resident_set_bytes(peak_rss_bytes);
+
+  // Returns true even if other metrics failed, since rss is reported.
+  return true;
+}
+
+}  // namespace tracing