gecko/mobile/android/base/MemoryMonitor.java

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/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko;
import org.mozilla.gecko.db.BrowserContract;
import org.mozilla.gecko.db.BrowserDB;
import org.mozilla.gecko.favicons.Favicons;
import org.mozilla.gecko.util.ThreadUtils;
import android.content.BroadcastReceiver;
import android.content.ComponentCallbacks2;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Build;
import android.util.Log;
/**
* This is a utility class to keep track of how much memory and disk-space pressure
* the system is under. It receives input from GeckoActivity via the onLowMemory() and
* onTrimMemory() functions, and also listens for some system intents related to
* disk-space notifications. Internally it will track how much memory and disk pressure
* the system is under, and perform various actions to help alleviate the pressure.
*
* Note that since there is no notification for when the system has lots of free memory
* again, this class also assumes that, over time, the system will free up memory. This
* assumption is implemented using a timer that slowly lowers the internal memory
* pressure state if no new low-memory notifications are received.
*
* Synchronization note: MemoryMonitor contains an inner class PressureDecrementer. Both
* of these classes may be accessed from various threads, and have both been designed to
* be thread-safe. In terms of lock ordering, code holding the PressureDecrementer lock
* is allowed to pick up the MemoryMonitor lock, but not vice-versa.
*/
class MemoryMonitor extends BroadcastReceiver {
private static final String LOGTAG = "GeckoMemoryMonitor";
private static final String ACTION_MEMORY_DUMP = "org.mozilla.gecko.MEMORY_DUMP";
private static final String ACTION_FORCE_PRESSURE = "org.mozilla.gecko.FORCE_MEMORY_PRESSURE";
// Memory pressue levels, keep in sync with those in AndroidJavaWrappers.h
private static final int MEMORY_PRESSURE_NONE = 0;
private static final int MEMORY_PRESSURE_CLEANUP = 1;
private static final int MEMORY_PRESSURE_LOW = 2;
private static final int MEMORY_PRESSURE_MEDIUM = 3;
private static final int MEMORY_PRESSURE_HIGH = 4;
private static MemoryMonitor sInstance = new MemoryMonitor();
static MemoryMonitor getInstance() {
return sInstance;
}
private final PressureDecrementer mPressureDecrementer;
private int mMemoryPressure;
private boolean mStoragePressure;
private MemoryMonitor() {
mPressureDecrementer = new PressureDecrementer();
mMemoryPressure = MEMORY_PRESSURE_NONE;
mStoragePressure = false;
}
public void init(Context context) {
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_DEVICE_STORAGE_LOW);
filter.addAction(Intent.ACTION_DEVICE_STORAGE_OK);
filter.addAction(ACTION_MEMORY_DUMP);
filter.addAction(ACTION_FORCE_PRESSURE);
context.getApplicationContext().registerReceiver(this, filter);
}
public void onLowMemory() {
Log.d(LOGTAG, "onLowMemory() notification received");
if (increaseMemoryPressure(MEMORY_PRESSURE_HIGH)) {
// We need to wait on Gecko here, because if we haven't reduced
// memory usage enough when we return from this, Android will kill us.
GeckoAppShell.sendEventToGeckoSync(GeckoEvent.createNoOpEvent());
}
}
public void onTrimMemory(int level) {
Log.d(LOGTAG, "onTrimMemory() notification received with level " + level);
if (Build.VERSION.SDK_INT < 14) {
// this won't even get called pre-ICS
return;
}
if (level >= ComponentCallbacks2.TRIM_MEMORY_COMPLETE) {
increaseMemoryPressure(MEMORY_PRESSURE_HIGH);
} else if (level >= ComponentCallbacks2.TRIM_MEMORY_MODERATE) {
increaseMemoryPressure(MEMORY_PRESSURE_MEDIUM);
} else if (level >= ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN) {
// includes TRIM_MEMORY_BACKGROUND
increaseMemoryPressure(MEMORY_PRESSURE_CLEANUP);
} else {
// levels down here mean gecko is the foreground process so we
// should be less aggressive with wiping memory as it may impact
// user experience.
increaseMemoryPressure(MEMORY_PRESSURE_LOW);
}
}
@Override
public void onReceive(Context context, Intent intent) {
if (Intent.ACTION_DEVICE_STORAGE_LOW.equals(intent.getAction())) {
Log.d(LOGTAG, "Device storage is low");
mStoragePressure = true;
ThreadUtils.postToBackgroundThread(new StorageReducer(context));
} else if (Intent.ACTION_DEVICE_STORAGE_OK.equals(intent.getAction())) {
Log.d(LOGTAG, "Device storage is ok");
mStoragePressure = false;
} else if (ACTION_MEMORY_DUMP.equals(intent.getAction())) {
String label = intent.getStringExtra("label");
if (label == null) {
label = "default";
}
GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent("Memory:Dump", label));
} else if (ACTION_FORCE_PRESSURE.equals(intent.getAction())) {
increaseMemoryPressure(MEMORY_PRESSURE_HIGH);
}
}
private boolean increaseMemoryPressure(int level) {
int oldLevel;
synchronized (this) {
// bump up our level if we're not already higher
if (mMemoryPressure > level) {
return false;
}
oldLevel = mMemoryPressure;
mMemoryPressure = level;
}
// since we don't get notifications for when memory pressure is off,
// we schedule our own timer to slowly back off the memory pressure level.
// note that this will reset the time to next decrement if the decrementer
// is already running, which is the desired behaviour because we just got
// a new low-mem notification.
mPressureDecrementer.start();
if (oldLevel == level) {
// if we're not going to a higher level we probably don't
// need to run another round of the same memory reductions
// we did on the last memory pressure increase.
return false;
}
// TODO hook in memory-reduction stuff for different levels here
if (level >= MEMORY_PRESSURE_MEDIUM) {
//Only send medium or higher events because that's all that is used right now
if (GeckoThread.checkLaunchState(GeckoThread.LaunchState.GeckoRunning)) {
GeckoAppShell.dispatchMemoryPressure();
}
Favicons.clearMemCache();
}
return true;
}
private boolean decreaseMemoryPressure() {
int newLevel;
synchronized (this) {
if (mMemoryPressure <= 0) {
return false;
}
newLevel = --mMemoryPressure;
}
Log.d(LOGTAG, "Decreased memory pressure to " + newLevel);
return true;
}
class PressureDecrementer implements Runnable {
private static final int DECREMENT_DELAY = 5 * 60 * 1000; // 5 minutes
private boolean mPosted;
synchronized void start() {
if (mPosted) {
// cancel the old one before scheduling a new one
ThreadUtils.getBackgroundHandler().removeCallbacks(this);
}
ThreadUtils.getBackgroundHandler().postDelayed(this, DECREMENT_DELAY);
mPosted = true;
}
@Override
public synchronized void run() {
if (!decreaseMemoryPressure()) {
// done decrementing, bail out
mPosted = false;
return;
}
// need to keep decrementing
ThreadUtils.getBackgroundHandler().postDelayed(this, DECREMENT_DELAY);
}
}
class StorageReducer implements Runnable {
private final Context mContext;
public StorageReducer(final Context context) {
this.mContext = context;
}
@Override
public void run() {
// this might get run right on startup, if so wait 10 seconds and try again
if (!GeckoThread.checkLaunchState(GeckoThread.LaunchState.GeckoRunning)) {
ThreadUtils.getBackgroundHandler().postDelayed(this, 10000);
return;
}
if (!mStoragePressure) {
// pressure is off, so we can abort
return;
}
BrowserDB.expireHistory(mContext.getContentResolver(),
BrowserContract.ExpirePriority.AGGRESSIVE);
BrowserDB.removeThumbnails(mContext.getContentResolver());
// TODO: drop or shrink disk caches
}
}
}