[tracing] Dump child processes' memory metrics in browser

components/tracing/process_metrics_memory_dump_provider_posix.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.

[Primiano Tucci (use gerrit), 2015/12/14 10:52:21]

_posix is a bit misleading here, as it suggests that this is also for mac, which
doesn't seem the case here.
I think it's saner to call this _linux.cc (which it's ok if it applies also to
android)

[ssid, 2016/01/04 20:54:38]

Done.

 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/trace_event/process_memory_maps_dump_provider.h"
+#include "components/tracing/process_metrics_memory_dump_provider.h"
 
+#include <fcntl.h>
+
+#include "base/files/file_util.h"
 #include "base/files/scoped_file.h"
 #include "base/format_macros.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/process_memory_dump.h"
 #include "base/trace_event/process_memory_maps.h"
 
-namespace base {
-namespace trace_event {
-
-// static
-FILE* ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = nullptr;
+namespace tracing {
 
 namespace {
 
+bool kernel_supports_rss_peak_reset = true;
+const char kClearPeakRssCommand[] = "5";
+
 const uint32 kMaxLineSize = 4096;
 
 bool ParseSmapsHeader(const char* header_line,
-                      ProcessMemoryMaps::VMRegion* region) {
+                      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 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 |=
-        ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
+        base::trace_event::ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
   }
   if (protection_flags[1] == 'w') {
     region->protection_flags |=
-        ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
+        base::trace_event::ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
   }
   if (protection_flags[2] == 'x') {
     region->protection_flags |=
-        ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
+        base::trace_event::ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
   }
 
   region->mapped_file = mapped_file;
-  TrimWhitespaceASCII(region->mapped_file, TRIM_ALL, &region->mapped_file);
+  base::TrimWhitespaceASCII(region->mapped_file, base::TRIM_ALL,
+                            &region->mapped_file);
 
   return res;
 }
 
 uint64 ReadCounterBytes(char* counter_line) {
   uint64 counter_value = 0;
   int res = sscanf(counter_line, "%*s %" SCNu64 " kB", &counter_value);
   DCHECK_EQ(1, res);
   return counter_value * 1024;
 }
 
-uint32 ParseSmapsCounter(char* counter_line,
-                         ProcessMemoryMaps::VMRegion* region) {
+uint32 ParseSmapsCounter(
+    char* counter_line,
+    base::trace_event::ProcessMemoryMaps::VMRegion* region) {
   // A smaps counter lines looks as follows: "RSS:  0 Kb\n"
   uint32 res = 1;
   char counter_name[20];
   int did_read = sscanf(counter_line, "%19[^\n ]", counter_name);
   DCHECK_EQ(1, did_read);
 
   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 ReadLinuxProcSmapsFile(FILE* smaps_file, ProcessMemoryMaps* pmm) {
+uint32 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 kNumExpectedCountersPerRegion = 6;
   uint32 counters_parsed_for_current_region = 0;
   uint32 num_valid_regions = 0;
-  ProcessMemoryMaps::VMRegion region;
+  base::trace_event::ProcessMemoryMaps::VMRegion region;
   bool should_add_current_region = false;
   for (;;) {
     line[0] = '\0';
     if (fgets(line, kMaxLineSize, smaps_file) == nullptr)
       break;
     DCHECK_GT(strlen(line), 0u);
     if (isxdigit(line[0]) && !isupper(line[0])) {
-      region = ProcessMemoryMaps::VMRegion();
+      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;
 }
 
 }  // namespace
 
 // static
-ProcessMemoryMapsDumpProvider* ProcessMemoryMapsDumpProvider::GetInstance() {
-  return Singleton<ProcessMemoryMapsDumpProvider,
-                   LeakySingletonTraits<ProcessMemoryMapsDumpProvider>>::get();
+FILE* ProcessMetricsMemoryDumpProvider::proc_smaps_for_testing = nullptr;
+
+void ProcessMetricsMemoryDumpProvider::DumpProcessTotals(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  const uint64 rss_bytes = rss_bytes_for_testing
+                               ? rss_bytes_for_testing
+                               : process_metrics_->GetWorkingSetSize();
+
+  uint64 peak_rss_bytes = 0;
+  peak_rss_bytes = process_metrics_->GetPeakWorkingSetSize();
+
+  // This file cannot be wriiten for other processes. So, do not try.
+  if (kernel_supports_rss_peak_reset && process_ == base::kNullProcessHandle) {
+    int clear_refs_fd = open("/proc/self/clear_refs", 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 {
+      kernel_supports_rss_peak_reset = false;
+    }
+    close(clear_refs_fd);
+  }
+
+  DCHECK(rss_bytes);
+  pmd->process_totals()->set_resident_set_bytes(rss_bytes);
+  pmd->process_totals()->set_peak_resident_set_bytes(peak_rss_bytes);
+  pmd->set_has_process_totals();
 }
 
-ProcessMemoryMapsDumpProvider::ProcessMemoryMapsDumpProvider() {
-}
-
-ProcessMemoryMapsDumpProvider::~ProcessMemoryMapsDumpProvider() {
-}
-
-// Called at trace dump point time. Creates a snapshot of the memory maps for
-// the current process.
-bool ProcessMemoryMapsDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
-                                                 ProcessMemoryDump* pmd) {
-  // Snapshot of memory maps is not taken for light dump requests.
-  if (args.level_of_detail == MemoryDumpLevelOfDetail::LIGHT)
-    return true;
+void ProcessMetricsMemoryDumpProvider::DumpProcessMemoryMaps(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  // Snapshot of memory maps is taken only for detailed dump requests.
+  if (args.level_of_detail !=
+      base::trace_event::MemoryDumpLevelOfDetail::DETAILED)
+    return;
 
   uint32 res = 0;
   if (UNLIKELY(proc_smaps_for_testing)) {
     res = ReadLinuxProcSmapsFile(proc_smaps_for_testing, pmd->process_mmaps());
   } else {
-    ScopedFILE smaps_file(fopen("/proc/self/smaps", "r"));
+    std::string file_name = "/proc/" + (process_ == base::kNullProcessHandle
+                                            ? "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 > 0) {
+  if (res)
     pmd->set_has_process_mmaps();

[Primiano Tucci (use gerrit), 2015/12/14 10:52:21]

what happens if something fails? we don't get any output anymore?
Not even a DCHECK?
Why not keeping returning true / false if this can fail?

[ssid, 2016/01/04 20:54:38]

Done.

-    return true;
-  }
-  return false;
 }
 
-}  // namespace trace_event
-}  // namespace base
+}  // namespace tracing