Consolidate code monitoring low memory kills and OOM kills to MemoryKillsMonitor on ChromeOS.

components/arc/metrics/oom_kills_monitor.cc

Index: components/arc/metrics/oom_kills_monitor.cc
diff --git a/components/arc/metrics/oom_kills_monitor.cc b/components/arc/metrics/oom_kills_monitor.cc
deleted file mode 100644
index 719b778eaf9dbc3e54d9939ce11a0eb2e6fe233d..0000000000000000000000000000000000000000
--- a/components/arc/metrics/oom_kills_monitor.cc
+++ /dev/null
@@ -1,206 +0,0 @@
-// Copyright 2016 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/arc/metrics/oom_kills_monitor.h"
-
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-
-#include <vector>
-
-#include "base/bind.h"
-#include "base/debug/leak_annotations.h"
-#include "base/files/file_util.h"
-#include "base/files/scoped_file.h"
-#include "base/location.h"
-#include "base/logging.h"
-#include "base/memory/ptr_util.h"
-#include "base/metrics/histogram_macros.h"
-#include "base/posix/safe_strerror.h"
-#include "base/sequenced_task_runner.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_piece.h"
-#include "base/strings/string_split.h"
-#include "base/time/time.h"
-#include "components/arc/metrics/oom_kills_histogram.h"
-#include "third_party/re2/src/re2/re2.h"
-#include "third_party/re2/src/re2/stringpiece.h"
-
-namespace arc {
-
-using base::StringPiece;
-
-using base::SequencedWorkerPool;
-using base::TimeDelta;
-
-namespace {
-
-int64_t GetTimestamp(const StringPiece& line) {
-  std::vector<StringPiece> fields = base::SplitStringPiece(
-      line, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
-
-  int64_t timestamp = -1;
-  // Timestamp is the third field in a line of /dev/kmsg.
-  if (fields.size() < 3 || !base::StringToInt64(fields[2], &timestamp))
-    return -1;
-  return timestamp;
-}
-
-bool GetTimeDelta(
-    const StringPiece& line, int64_t* last, TimeDelta* time_delta) {
-  int64_t now = GetTimestamp(line);
-  if (now < 0)
-    return false;
-
-  // Sets to |kMaxOomMemoryKillTimeSecs| for the first kill event.
-  if (*last < 0)
-    *time_delta = TimeDelta::FromSeconds(kMaxOomMemoryKillTimeDeltaSecs);
-  else
-    *time_delta = TimeDelta::FromMicroseconds(now - *last);
-
-  *last = now;
-
-  return true;
-}
-
-void LogOOMKill(const StringPiece& line) {
-  static int64_t last_timestamp = -1;
-  static int oom_kills = 0;
-
-  // Sample log line:
-  // 3,1362,97646497541,-;Out of memory: Kill process 29582 (android.vending)
-  // score 961 or sacrifice child.
-  int oom_badness;
-  TimeDelta time_delta;
-  if (RE2::PartialMatch(re2::StringPiece(line.data(), line.size()),
-                        "Out of memory: Kill process .* score (\\d+)",
-                        &oom_badness)) {
-    ++oom_kills;
-    // Report the cumulative count of killed process in one login session.
-    // For example if there are 3 processes killed, it would report 1 for the
-    // first kill, 2 for the second kill, then 3 for the final kill.
-    // It doesn't report a final count at the end of a user session because
-    // the code runs in a dedicated thread and never ends until browser shutdown
-    // (or logout on Chrome OS). And on browser shutdown the thread may be
-    // terminated brutally so there's no chance to execute a "final" block.
-    // More specifically, code outside the main loop of OomKillsMonitor::Run()
-    // are not guaranteed to be executed.
-    UMA_HISTOGRAM_CUSTOM_COUNTS(
-        "Arc.OOMKills.Count", oom_kills, 1, 1000, 1001);
-
-    // In practice most process has oom_badness < 1000, but
-    // strictly speaking the number could be [1, 2000]. What it really
-    // means is the baseline, proportion of memory used (normalized to
-    // [0, 1000]), plus an adjustment score oom_score_adj [-1000, 1000],
-    // truncated to 1 if negative (0 means never kill).
-    // Ref: https://lwn.net/Articles/396552/
-    UMA_HISTOGRAM_CUSTOM_COUNTS(
-        "Arc.OOMKills.Score", oom_badness, 1, 2000, 2001);
-
-    if (GetTimeDelta(line, &last_timestamp, &time_delta)) {
-      UMA_HISTOGRAM_OOM_KILL_TIME_INTERVAL(
-          "Arc.OOMKills.TimeDelta", time_delta);
-    }
-  }
-}
-
-void LogLowMemoryKill(const StringPiece& line) {
-  static int64_t last_timestamp = -1;
-  static int low_memory_kills = 0;
-
-  int freed_size;
-  TimeDelta time_delta;
-  // Sample log line:
-  // 6,2302,533604004,-;lowmemorykiller: Killing 'externalstorage' (21742),
-  // adj 1000,\x0a   to free 27320kB on behalf of 'kswapd0' (47) because\x0a
-  // cache 181920kB is below limit 184320kB for oom_score_adj 1000\x0a
-  // Free memory is 1228kB above reserved
-  if (RE2::PartialMatch(re2::StringPiece(line.data(), line.size()),
-                        "lowmemorykiller: .* to free (\\d+)kB",
-                        &freed_size)) {
-    // Report the count for each lowmemorykill event. See comments in
-    // LogOOMKill().
-    ++low_memory_kills;
-    UMA_HISTOGRAM_CUSTOM_COUNTS(
-        "Arc.LowMemoryKiller.Count", low_memory_kills, 1, 1000, 1001);
-
-    UMA_HISTOGRAM_MEMORY_KB("Arc.LowMemoryKiller.FreedSize", freed_size);
-
-    if (GetTimeDelta(line, &last_timestamp, &time_delta)) {
-      UMA_HISTOGRAM_OOM_KILL_TIME_INTERVAL(
-          "Arc.LowMemoryKiller.TimeDelta", time_delta);
-    }
-  }
-}
-
-}  // namespace
-
-OomKillsMonitor::Handle::Handle(OomKillsMonitor* outer) : outer_(outer) {
-  DCHECK(outer_);
-}
-
-OomKillsMonitor::Handle::~Handle() {
-  outer_->is_shutting_down_.Set();
-}
-
-OomKillsMonitor::OomKillsMonitor() {
-  base::SimpleThread::Options non_joinable_options;
-  non_joinable_options.joinable = false;
-  non_joinable_worker_thread_ = base::MakeUnique<base::DelegateSimpleThread>(
-      this, "oom_kills_monitor", non_joinable_options);
-  non_joinable_worker_thread_->Start();
-}
-
-OomKillsMonitor::~OomKillsMonitor() {
-  // The instance has to be leaked on shutdown as it is referred to by a
-  // non-joinable thread but ~OomKillsMonitor() can't be explicitly deleted as
-  // it overrides ~SimpleThread(), it should nevertheless never be invoked.
-  NOTREACHED();
-}
-
-// static
-OomKillsMonitor::Handle OomKillsMonitor::StartMonitoring() {
-#if DCHECK_IS_ON()
-  static volatile bool monitoring_active = false;
-  DCHECK(!monitoring_active);
-  monitoring_active = true;
-#endif
-
-  // Instantiate the OomKillsMonitor and its underlying thread. The
-  // OomKillsMonitor itself has to be leaked on shutdown per having a
-  // non-joinable thread associated to its state. The OomKillsMonitor::Handle
-  // will notify the OomKillsMonitor when it is destroyed so that the underlying
-  // thread can at a minimum not do extra work during shutdown.
-  OomKillsMonitor* instance = new OomKillsMonitor;
-  ANNOTATE_LEAKING_OBJECT_PTR(instance);
-  return Handle(instance);
-}
-
-void OomKillsMonitor::Run() {
-  base::ScopedFILE kmsg_handle(
-      base::OpenFile(base::FilePath("/dev/kmsg"), "r"));
-  if (!kmsg_handle) {
-    LOG(WARNING) << "Open /dev/kmsg failed: " << base::safe_strerror(errno);
-    return;
-  }
-  // Skip kernel messages prior to the instantiation of this object to avoid
-  // double reporting.
-  fseek(kmsg_handle.get(), 0, SEEK_END);
-
-  static const int kMaxBufSize = 512;
-  char buf[kMaxBufSize];
-
-  while (fgets(buf, kMaxBufSize, kmsg_handle.get())) {
-    if (is_shutting_down_.IsSet()) {
-      DVLOG(1) << "Chrome is shutting down, exit now.";
-      break;
-    }
-    const StringPiece buf_string(buf);
-    LogOOMKill(buf_string);
-    LogLowMemoryKill(buf_string);
-  }
-}
-
-}  // namespace arc