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// 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.
#ifndef CHROME_BROWSER_RESOURCE_COORDINATOR_TAB_MANAGER_DELEGATE_CHROMEOS_H_
#define CHROME_BROWSER_RESOURCE_COORDINATOR_TAB_MANAGER_DELEGATE_CHROMEOS_H_
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "base/containers/flat_map.h"
#include "base/gtest_prod_util.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/process/process.h"
#include "base/timer/timer.h"
#include "chrome/browser/chromeos/arc/process/arc_process.h"
#include "chrome/browser/resource_coordinator/tab_manager.h"
#include "chrome/browser/resource_coordinator/tab_stats.h"
#include "chrome/browser/ui/browser_list_observer.h"
#include "chromeos/dbus/debug_daemon_client.h"
#include "components/arc/common/process.mojom.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
#include "ui/wm/public/activation_change_observer.h"
namespace resource_coordinator {
// Possible types of Apps/Tabs processes. From most important to least
// important.
enum class ProcessType {
// Conceptually, the system cannot have both FOCUSED_TAB and FOCUSED_APP at
// the same time, but because Chrome cannot retrieve FOCUSED_APP status
// synchronously, Chrome may still see both at the same time. When that
// happens, treat FOCUSED_TAB as the most important since the (synchronously
// retrieved) tab information is more reliable and up-to-date.
FOCUSED_TAB = 1,
FOCUSED_APP = 2,
// Important apps are protected in two ways: 1) Chrome never kills them, and
// 2) the kernel is still allowed to kill them, but their OOM adjustment
// scores are better than BACKGROUND_TABs and BACKGROUND_APPs.
IMPORTANT_APP = 3,
BACKGROUND_APP = 4,
BACKGROUND_TAB = 5,
UNKNOWN_TYPE = 6,
};
// The Chrome OS TabManagerDelegate is responsible for keeping the
// renderers' scores up to date in /proc/<pid>/oom_score_adj.
class TabManagerDelegate : public wm::ActivationChangeObserver,
public content::NotificationObserver,
public BrowserListObserver {
public:
class MemoryStat;
explicit TabManagerDelegate(const base::WeakPtr<TabManager>& tab_manager);
TabManagerDelegate(const base::WeakPtr<TabManager>& tab_manager,
TabManagerDelegate::MemoryStat* mem_stat);
~TabManagerDelegate() override;
void OnBrowserSetLastActive(Browser* browser) override;
// aura::ActivationChangeObserver overrides.
void OnWindowActivated(wm::ActivationChangeObserver::ActivationReason reason,
aura::Window* gained_active,
aura::Window* lost_active) override;
// Kills a process on memory pressure.
void LowMemoryKill(DiscardReason reason);
// Returns oom_score_adj of a process if the score is cached by |this|.
// If couldn't find the score in the cache, returns -1001 since the valid
// range of oom_score_adj is [-1000, 1000].
int GetCachedOomScore(base::ProcessHandle process_handle);
// Called when the timer fires, sets oom_adjust_score for all renderers.
void AdjustOomPriorities(const TabStatsList& tab_list);
// Returns true if the process has recently been killed.
// Virtual for unit testing.
virtual bool IsRecentlyKilledArcProcess(const std::string& process_name,
const base::TimeTicks& now);
protected:
// Kills an ARC process. Returns true if the kill request is successfully sent
// to Android. Virtual for unit testing.
virtual bool KillArcProcess(const int nspid);
// Kills a tab. Returns true if the tab is killed successfully.
// Virtual for unit testing.
virtual bool KillTab(const TabStats& tab_stats, DiscardReason reason);
// Get debugd client instance. Virtual for unit testing.
virtual chromeos::DebugDaemonClient* GetDebugDaemonClient();
private:
FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest, CandidatesSorted);
FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest,
CandidatesSortedWithFocusedAppAndTab);
FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest,
DoNotKillRecentlyKilledArcProcesses);
FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest, IsRecentlyKilledArcProcess);
FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest, KillMultipleProcesses);
FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest, SetOomScoreAdj);
class Candidate;
class FocusedProcess;
friend std::ostream& operator<<(std::ostream& out,
const Candidate& candidate);
// content::NotificationObserver:
void Observe(int type,
const content::NotificationSource& source,
const content::NotificationDetails& details) override;
// Pair to hold child process host id and ProcessHandle.
typedef std::pair<int, base::ProcessHandle> ProcessInfo;
// Cache OOM scores in memory.
typedef base::flat_map<base::ProcessHandle, int> ProcessScoreMap;
// A map from an ARC process name to a monotonic timestamp when it's killed.
typedef base::flat_map<std::string, base::TimeTicks> KilledArcProcessesMap;
// Get the list of candidates to kill, sorted by descending importance.
static std::vector<Candidate> GetSortedCandidates(
const TabStatsList& tab_list,
const std::vector<arc::ArcProcess>& arc_processes);
// Sets OOM score for the focused tab.
void OnFocusTabScoreAdjustmentTimeout();
// Kills a process after getting all info of tabs and apps.
void LowMemoryKillImpl(DiscardReason reason,
const TabStatsList& tab_list,
const std::vector<arc::ArcProcess>& arc_processes);
// Public interface to adjust OOM scores.
void AdjustOomPriorities(const TabStatsList& tab_list,
const std::vector<arc::ArcProcess>& arc_processes);
// Sets a newly focused tab the highest priority process if it wasn't.
void AdjustFocusedTabScore(base::ProcessHandle pid);
// Called by AdjustOomPriorities. Runs on the main thread.
void AdjustOomPrioritiesImpl(const TabStatsList& tab_list,
std::vector<arc::ArcProcess> arc_processes);
// Sets OOM score for processes in the range [|rbegin|, |rend|) to integers
// distributed evenly in [|range_begin|, |range_end|).
// The new score is set in |new_map|.
void DistributeOomScoreInRange(
std::vector<TabManagerDelegate::Candidate>::const_iterator begin,
std::vector<TabManagerDelegate::Candidate>::const_iterator end,
int range_begin,
int range_end,
ProcessScoreMap* new_map);
// Changes |candidates|' OOM scores to |score|. The new scores are set in
// |new_map|.
void SetOomScore(const std::vector<TabManagerDelegate::Candidate>& candidates,
int score,
ProcessScoreMap* new_map);
// Initiates an oom priority adjustment.
void ScheduleEarlyOomPrioritiesAdjustment();
// Returns a TimeDelta object that represents a minimum delay for killing
// the same ARC process again. ARC processes sometimes respawn right after
// being killed. In that case, killing them every time is just a waste of
// resources.
static constexpr base::TimeDelta GetArcRespawnKillDelay() {
return base::TimeDelta::FromSeconds(60);
}
// The lowest OOM adjustment score that will make the process non-killable.
static const int kLowestOomScore;
// Holds a reference to the owning TabManager.
const base::WeakPtr<TabManager> tab_manager_;
// Registrar to receive renderer notifications.
content::NotificationRegistrar registrar_;
// Timer to guarantee that the tab or app is focused for a certain amount of
// time.
base::OneShotTimer focus_process_score_adjust_timer_;
// Holds the info of the newly focused tab or app. Its OOM score would be
// adjusted when |focus_process_score_adjust_timer_| is expired.
std::unique_ptr<FocusedProcess> focused_process_;
// Map maintaining the process handle - oom_score mapping.
ProcessScoreMap oom_score_map_;
// Map maintaing ARC process names and their last killed time.
KilledArcProcessesMap recently_killed_arc_processes_;
// Util for getting system memory status.
std::unique_ptr<TabManagerDelegate::MemoryStat> mem_stat_;
// Weak pointer factory used for posting tasks to other threads.
base::WeakPtrFactory<TabManagerDelegate> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(TabManagerDelegate);
};
// On ARC enabled machines, either a tab or an app could be a possible
// victim of low memory kill process. This is a helper class which holds a
// pointer to an app or a tab (but not both) to facilitate prioritizing the
// victims.
class TabManagerDelegate::Candidate {
public:
explicit Candidate(const TabStats* tab)
: tab_(tab), app_(nullptr), process_type_(GetProcessTypeInternal()) {
DCHECK(tab_);
}
explicit Candidate(const arc::ArcProcess* app)
: tab_(nullptr), app_(app), process_type_(GetProcessTypeInternal()) {
DCHECK(app_);
}
// Move-only class.
Candidate(Candidate&&) = default;
Candidate& operator=(Candidate&& other);
// Higher priority first.
bool operator<(const Candidate& rhs) const;
const TabStats* tab() const { return tab_; }
const arc::ArcProcess* app() const { return app_; }
ProcessType process_type() const { return process_type_; }
private:
// Derive process type for this candidate. Used to initialize |process_type_|.
ProcessType GetProcessTypeInternal() const;
const TabStats* tab_;
const arc::ArcProcess* app_;
ProcessType process_type_;
DISALLOW_COPY_AND_ASSIGN(Candidate);
};
// A thin wrapper over library process_metric.h to get memory status so unit
// test get a chance to mock out.
class TabManagerDelegate::MemoryStat {
public:
MemoryStat() {}
virtual ~MemoryStat() {}
// Returns target size of memory to free given current memory pressure and
// pre-configured low memory margin.
virtual int TargetMemoryToFreeKB();
// Returns estimated memory to be freed if the process |pid| is killed.
virtual int EstimatedMemoryFreedKB(base::ProcessHandle pid);
private:
// Returns the low memory margin system config. Low memory condition is
// reported if available memory is under the number.
static int LowMemoryMarginKB();
// Reads in an integer.
static int ReadIntFromFile(const char* file_name, int default_val);
};
} // namespace resource_coordinator
#endif // CHROME_BROWSER_RESOURCE_COORDINATOR_TAB_MANAGER_DELEGATE_CHROMEOS_H_