Bug 822325: Implement an LRU pool for background app processes. The L…

…RU app will get the smallest oom_adj and get killed last. r=khuey
mozilla-spidermonkey · Oct 1, 2013 · 980d515 · 980d515
1 parent 90f552b
commit 980d515
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Showing 11 changed files with 441 additions and 18 deletions.
diff --git a/b2g/app/b2g.js b/b2g/app/b2g.js
@@ -603,6 +603,11 @@ pref("dom.ipc.processPriorityManager.enabled", true);
 pref("dom.ipc.processPriorityManager.backgroundGracePeriodMS", 1000);
 pref("dom.ipc.processPriorityManager.temporaryPriorityLockMS", 5000);
 
+// Number of different background levels for background processes.  We use
+// these different levels to force the low-memory killer to kill processes in
+// a LRU order.
+pref("dom.ipc.processPriorityManager.backgroundLRUPoolLevels", 5);
+
 // Kernel parameters for process priorities.  These affect how processes are
 // killed on low-memory and their relative CPU priorities.
 //

diff --git a/dom/browser-element/mochitest/browserElementTestHelpers.js b/dom/browser-element/mochitest/browserElementTestHelpers.js
@@ -46,6 +46,7 @@ const browserElementTestHelpers = {
   enableProcessPriorityManager: function() {
     this._setPref('dom.ipc.processPriorityManager.testMode', true);
     this._setPref('dom.ipc.processPriorityManager.enabled', true);
+    this._setPref('dom.ipc.processPriorityManager.backgroundLRUPoolLevels', 2);
   },
 
   setEnabledPref: function(value) {
@@ -193,6 +194,37 @@ function expectPriorityChange(childID, expectedPriority,
   return deferred.promise;
 }
 
+// Returns a promise which is resolved or rejected the next time the background
+// process childID changes its priority.  We resolve if the backgroundLRU
+// matches expectedBackgroundLRU and we reject otherwise.
+
+function expectPriorityWithBackgroundLRUSet(childID, expectedBackgroundLRU) {
+  var deferred = Promise.defer();
+
+  browserElementTestHelpers.addProcessPriorityObserver(
+    'process-priority-with-background-LRU-set',
+    function(subject, topic, data) {
+
+      [id, priority, cpuPriority, backgroundLRU] = data.split(":");
+      if (id != childID) {
+        return;
+      }
+
+      is(backgroundLRU, expectedBackgroundLRU,
+         'Expected backgroundLRU ' + backgroundLRU + ' of childID ' + childID +
+         ' to change to ' + expectedBackgroundLRU);
+
+      if (backgroundLRU == expectedBackgroundLRU) {
+        deferred.resolve();
+      } else {
+        deferred.reject();
+      }
+    }
+  );
+
+  return deferred.promise;
+}
+
 // Returns a promise which is resolved the first time the given iframe fires
 // the mozbrowser##eventName event.
 function expectMozbrowserEvent(iframe, eventName) {

diff --git a/dom/browser-element/mochitest/priority/Makefile.in b/dom/browser-element/mochitest/priority/Makefile.in
@@ -23,6 +23,7 @@ MOCHITEST_FILES = \
 	test_HighPriorityDowngrade.html \
 	test_HighPriorityDowngrade2.html \
 	test_Background.html \
+	test_BackgroundLRU.html \
 	test_Audio.html \
 	file_Audio.html \
 	silence.ogg \

diff --git a/dom/browser-element/mochitest/priority/test_BackgroundLRU.html b/dom/browser-element/mochitest/priority/test_BackgroundLRU.html
@@ -0,0 +1,67 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+Test that calling setVisible('false') on two iframes causes the former one's priority with background LRU to
+change.
+-->
+<head>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="application/javascript" src="../browserElementTestHelpers.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+
+<script type="application/javascript;version=1.7">
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+browserElementTestHelpers.setEnabledPref(true);
+browserElementTestHelpers.addPermission();
+browserElementTestHelpers.enableProcessPriorityManager();
+SpecialPowers.addPermission("embed-apps", true, document);
+
+function runTest() {
+  var iframe1 = document.createElement('iframe');
+  iframe1.setAttribute('mozbrowser', true);
+  iframe1.src = 'file_MultipleFrames.html';
+
+  var iframe2 = null;
+  var childID = null;
+
+  expectProcessCreated().then(function(chid) {
+    childID = chid;
+    return expectPriorityChange(childID, 'FOREGROUND');
+  }).then(function() {
+    return expectMozbrowserEvent(iframe1, 'openwindow');
+  }).then(function() {
+    var p = expectPriorityChange(childID, 'BACKGROUND');
+    iframe1.setVisible(false);
+    return p;
+  }).then(function() {
+    iframe2 = document.createElement('iframe');
+    iframe2.setAttribute('mozbrowser', true);
+    iframe2.setAttribute('mozapp', 'http://example.org/manifest.webapp');
+    iframe2.src = browserElementTestHelpers.emptyPage1;
+
+    document.body.appendChild(iframe2);
+
+    // At this point, we should have iframe1 in background already.
+    // We wait until another one is set to background, too.
+    // Once there are two in background, the first one (LRU order)
+    // should have 'backgroundLRU' equals 1
+    var p = expectPriorityWithBackgroundLRUSet(childID, '1');
+    iframe2.setVisible(false);
+    document.body.removeChild(iframe2);
+
+    return p;
+
+  }).then(SimpleTest.finish);
+
+  document.body.appendChild(iframe1);
+}
+
+addEventListener('testready', runTest);
+
+</script>
+</body>
+</html>