Bug 1334210 - Handle Large-Allocation process exhaustion more smoothly, r=ehsan

MozReview-Commit-ID: KxnFTSXxWVi

browser/modules/E10SUtils.jsm

@@ -157,10 +157,12 @@ this.E10SUtils = {
     if (aDocShell.QueryInterface(Ci.nsIDocShellTreeItem).sameTypeParent)
       return true;
 
-    // If we are in a fresh process, and it wouldn't be content visible to
-    // change processes, we want to load into a new process so that we can throw
+    // If we are in a Large-Allocation process, and it wouldn't be content visible
+    // to change processes, we want to load into a new process so that we can throw
     // this one out.
-    if (aDocShell.inFreshProcess && aDocShell.isOnlyToplevelInTabGroup) {
+    if (aDocShell.inLargeAllocProcess &&
+        !aDocShell.awaitingLargeAlloc &&
+        aDocShell.isOnlyToplevelInTabGroup) {
       return false;
     }
 

docshell/base/nsDocShell.cpp

@@ -14854,8 +14854,22 @@ nsDocShell::GetIsOnlyToplevelInTabGroup(bool* aResult)
 }
 
 NS_IMETHODIMP
-nsDocShell::GetInFreshProcess(bool* aResult)
+nsDocShell::GetAwaitingLargeAlloc(bool* aResult)
 {
-  *aResult = TabChild::GetWasFreshProcess();
+  MOZ_ASSERT(aResult);
+  nsCOMPtr<nsITabChild> tabChild = GetTabChild();
+  if (!tabChild) {
+    *aResult = false;
+    return NS_OK;
+  }
+  *aResult = static_cast<TabChild*>(tabChild.get())->IsAwaitingLargeAlloc();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShell::GetInLargeAllocProcess(bool* aResult)
+{
+  MOZ_ASSERT(aResult);
+  *aResult = TabChild::InLargeAllocProcess();
   return NS_OK;
 }

docshell/base/nsIDocShell.idl

@@ -1127,7 +1127,14 @@ interface nsIDocShell : nsIDocShellTreeItem
   [infallible] readonly attribute boolean isOnlyToplevelInTabGroup;
 
   /**
-   * Returns `true` if this docshell was created by a Large-Allocation load.
+   * Returns `true` if this docshell is loaded within a Large-Allocation
+   * process.
    */
-  [infallible] readonly attribute boolean inFreshProcess;
+  [infallible] readonly attribute boolean inLargeAllocProcess;
+
+  /**
+   * Returns `true` if this docshell was created due to a Large-Allocation
+   * header, and has not seen the initiating load yet.
+   */
+  [infallible] readonly attribute boolean awaitingLargeAlloc;
 };

dom/base/nsContentUtils.cpp

@@ -9709,8 +9709,8 @@ nsContentUtils::AttemptLargeAllocationLoad(nsIHttpChannel* aChannel)
   TabChild* tabChild = TabChild::GetFrom(outer->AsOuter());
   NS_ENSURE_TRUE(tabChild, false);
 
-  if (tabChild->TakeIsFreshProcess())  {
-    NS_WARNING("Already in a fresh process, ignoring Large-Allocation header!");
+  if (tabChild->TakeAwaitingLargeAlloc())  {
+    NS_WARNING("In a Large-Allocation TabChild, ignoring Large-Allocation header!");
     outer->SetLargeAllocStatus(LargeAllocStatus::SUCCESS);
     return false;
   }

dom/interfaces/base/nsITabChild.idl

@@ -34,7 +34,5 @@ interface nsITabChild : nsISupports
                                   [array, size_is(linksCount)] in nsIDroppedLinkItem links);
 
   readonly attribute uint64_t tabId;
-
-  readonly attribute bool isInFreshProcess;
 };
 

dom/ipc/ContentParent.cpp

@@ -580,8 +580,13 @@ ContentParent::JoinAllSubprocesses()
 ContentParent::GetNewOrUsedBrowserProcess(const nsAString& aRemoteType,
                                           ProcessPriority aPriority,
                                           ContentParent* aOpener,
-                                          bool aLargeAllocationProcess)
+                                          bool aLargeAllocationProcess,
+                                          bool* aNew)
 {
+  if (aNew) {
+    *aNew = false;
+  }
+
   if (!sBrowserContentParents) {
     sBrowserContentParents =
       new nsClassHashtable<nsStringHashKey, nsTArray<ContentParent*>>;
@@ -622,6 +627,9 @@ ContentParent::GetNewOrUsedBrowserProcess(const nsAString& aRemoteType,
   }
 
   RefPtr<ContentParent> p = new ContentParent(aOpener, contentProcessType);
+  if (aNew) {
+    *aNew = true;
+  }
 
   if (!p->LaunchSubprocess(aPriority)) {
     return nullptr;
@@ -901,6 +909,7 @@ ContentParent::CreateBrowser(const TabContext& aContext,
     openerTabId = TabParent::GetTabIdFrom(docShell);
   }
 
+  bool newProcess = false;
   RefPtr<nsIContentParent> constructorSender;
   if (isInContentProcess) {
     MOZ_ASSERT(aContext.IsMozBrowserElement());
@@ -918,7 +927,7 @@ ContentParent::CreateBrowser(const TabContext& aContext,
 
       constructorSender =
         GetNewOrUsedBrowserProcess(remoteType, initialPriority, nullptr,
-                                   aFreshProcess);
+                                   aFreshProcess, &newProcess);
       if (!constructorSender) {
         return nullptr;
       }
@@ -966,7 +975,10 @@ ContentParent::CreateBrowser(const TabContext& aContext,
       constructorSender->IsForBrowser());
 
     if (aFreshProcess) {
-      Unused << browser->SendSetFreshProcess();
+      // Tell the TabChild object that it was created due to a Large-Allocation
+      // request, and whether or not that Large-Allocation request succeeded at
+      // creating a new content process.
+      Unused << browser->SendSetIsLargeAllocation(true, newProcess);
     }
 
     if (browser) {

dom/ipc/ContentParent.h

@@ -148,7 +148,8 @@ public:
                              hal::ProcessPriority aPriority =
                              hal::ProcessPriority::PROCESS_PRIORITY_FOREGROUND,
                              ContentParent* aOpener = nullptr,
-                             bool aLargeAllocationProcess = false);
+                             bool aLargeAllocationProcess = false,
+                             bool* anew = nullptr);
 
   /**
    * Get or create a content process for the given TabContext.  aFrameElement

dom/ipc/PBrowser.ipdl

@@ -908,7 +908,7 @@ child:
      * Tell the child that it is a fresh process created for a Large-Allocation
      * load.
      */
-    async SetFreshProcess();
+    async SetIsLargeAllocation(bool aIsLA, bool aNewProcess);
 
 /*
  * FIXME: write protocol!

dom/ipc/TabChild.cpp

@@ -155,7 +155,7 @@ static const char BEFORE_FIRST_PAINT[] = "before-first-paint";
 
 typedef nsDataHashtable<nsUint64HashKey, TabChild*> TabChildMap;
 static TabChildMap* sTabChildren;
-bool TabChild::sWasFreshProcess = false;
+bool TabChild::sInLargeAllocProcess = false;
 
 TabChildBase::TabChildBase()
   : mTabChildGlobal(nullptr)
@@ -381,7 +381,7 @@ TabChild::TabChild(nsIContentChild* aManager,
   , mParentIsActive(false)
   , mDidSetRealShowInfo(false)
   , mDidLoadURLInit(false)
-  , mIsFreshProcess(false)
+  , mAwaitingLA(false)
   , mSkipKeyPress(false)
   , mLayerObserverEpoch(0)
 #if defined(XP_WIN) && defined(ACCESSIBILITY)
@@ -3100,19 +3100,25 @@ TabChild::RecvThemeChanged(nsTArray<LookAndFeelInt>&& aLookAndFeelIntCache)
 }
 
 mozilla::ipc::IPCResult
-TabChild::RecvSetFreshProcess()
+TabChild::RecvSetIsLargeAllocation(const bool& aIsLA, const bool& aNewProcess)
 {
-  MOZ_ASSERT(!sWasFreshProcess, "Can only be a fresh process once!");
-  mIsFreshProcess = true;
+  mAwaitingLA = aIsLA;
+  sInLargeAllocProcess = aIsLA && aNewProcess;
   return IPC_OK();
 }
 
-NS_IMETHODIMP
-TabChild::GetIsInFreshProcess(bool* aResult)
+bool
+TabChild::IsAwaitingLargeAlloc()
 {
-  MOZ_ASSERT(aResult);
-  *aResult = mIsFreshProcess || sWasFreshProcess;
-  return NS_OK;
+  return mAwaitingLA;
+}
+
+bool
+TabChild::TakeAwaitingLargeAlloc()
+{
+  bool awaiting = mAwaitingLA;
+  mAwaitingLA = false;
+  return awaiting;
 }
 
 mozilla::plugins::PPluginWidgetChild*

dom/ipc/TabChild.h

@@ -661,30 +661,23 @@ public:
   uintptr_t GetNativeWindowHandle() const { return mNativeWindowHandle; }
 #endif
 
-  bool TakeIsFreshProcess()
+  // These methods return `true` if this TabChild is currently awaiting a
+  // Large-Allocation header.
+  bool TakeAwaitingLargeAlloc();
+  bool IsAwaitingLargeAlloc();
+
+  // Returns `true` if this this process was created to load a docshell in a
+  // "Fresh Process". This value is initialized to `false`, and is set to `true`
+  // in RecvSetFreshProcess.
+  static bool InLargeAllocProcess()
   {
-    if (mIsFreshProcess) {
-      MOZ_ASSERT(!sWasFreshProcess,
-                 "At most one tabGroup may be a fresh process per process");
-      sWasFreshProcess = true;
-      mIsFreshProcess = false;
-      return true;
-    }
-    return false;
+    return sInLargeAllocProcess;
   }
 
   already_AddRefed<nsISHistory> GetRelatedSHistory();
 
   mozilla::dom::TabGroup* TabGroup();
 
-  // Returns `true` if this this process was created to load a docshell in a
-  // "Fresh Process". This value is initialized to `false`, and is set to `true`
-  // in RecvSetFreshProcess.
-  static bool GetWasFreshProcess()
-  {
-    return sWasFreshProcess;
-  }
-
 protected:
   virtual ~TabChild();
 
@@ -722,7 +715,8 @@ protected:
 
   virtual mozilla::ipc::IPCResult RecvNotifyPartialSHistoryDeactive() override;
 
-  virtual mozilla::ipc::IPCResult RecvSetFreshProcess() override;
+  virtual mozilla::ipc::IPCResult RecvSetIsLargeAllocation(const bool& aIsLA,
+                                                           const bool& aNewProcess) override;
 
 private:
   void HandleDoubleTap(const CSSPoint& aPoint, const Modifiers& aModifiers,
@@ -813,7 +807,7 @@ private:
   CSSSize mUnscaledInnerSize;
   bool mDidSetRealShowInfo;
   bool mDidLoadURLInit;
-  bool mIsFreshProcess;
+  bool mAwaitingLA;
 
   bool mSkipKeyPress;
 
@@ -834,7 +828,7 @@ private:
   uintptr_t mNativeWindowHandle;
 #endif // defined(XP_WIN)
 
-  static bool sWasFreshProcess;
+  static bool sInLargeAllocProcess;
 
   DISALLOW_EVIL_CONSTRUCTORS(TabChild);
 };

dom/tests/browser/browser_largeAllocation.js

@@ -46,12 +46,10 @@ function getPID(aBrowser) {
   });
 }
 
-function getIsFreshProcess(aBrowser) {
+function getInLAProc(aBrowser) {
   return ContentTask.spawn(aBrowser, null, () => {
     try {
-      return docShell.QueryInterface(Ci.nsIInterfaceRequestor)
-                     .getInterface(Ci.nsITabChild)
-                     .isInFreshProcess;
+      return docShell.inLargeAllocProcess;
     } catch (e) {
       // This must be a non-remote browser, which means it is not fresh
       return false;
@@ -76,7 +74,7 @@ add_task(function*() {
   yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
     info("Starting test 0");
     let pid1 = yield getPID(aBrowser);
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     let epc = expectProcessCreated();
     yield ContentTask.spawn(aBrowser, TEST_URI, TEST_URI => {
@@ -89,7 +87,7 @@ add_task(function*() {
     let pid2 = yield getPID(aBrowser);
 
     isnot(pid1, pid2, "The pids should be different between the initial load and the new load");
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
   });
 
   // When a Large-Allocation document is loaded in an iframe, the header should
@@ -97,7 +95,7 @@ add_task(function*() {
   yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
     info("Starting test 1");
     let pid1 = yield getPID(aBrowser);
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     // Fail the test if we create a process
     let stopExpectNoProcess = expectNoProcess();
@@ -116,7 +114,7 @@ add_task(function*() {
     let pid2 = yield getPID(aBrowser);
 
     is(pid1, pid2, "The PID should not have changed");
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     stopExpectNoProcess();
   });
@@ -125,7 +123,7 @@ add_task(function*() {
   yield BrowserTestUtils.withNewTab("http://example.com", function*(aBrowser) {
     info("Starting test 2");
     let pid1 = yield getPID(aBrowser);
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     // Fail the test if we create a process
     let stopExpectNoProcess = expectNoProcess();
@@ -152,7 +150,7 @@ add_task(function*() {
     let pid2 = yield getPID(aBrowser);
 
     is(pid1, pid2, "The PID should not have changed");
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     stopExpectNoProcess();
   });
@@ -161,7 +159,7 @@ add_task(function*() {
   yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
     info("Starting test 3");
     let pid1 = yield getPID(aBrowser);
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     let epc = expectProcessCreated();
 
@@ -174,7 +172,7 @@ add_task(function*() {
     let pid2 = yield getPID(aBrowser);
 
     isnot(pid1, pid2);
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
 
     yield BrowserTestUtils.browserLoaded(aBrowser);
 
@@ -186,7 +184,7 @@ add_task(function*() {
 
     // We should have been kicked out of the large-allocation process by the
     // load, meaning we're back in a non-fresh process
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     epc = expectProcessCreated();
 
@@ -200,14 +198,14 @@ add_task(function*() {
 
     isnot(pid1, pid4);
     isnot(pid2, pid4);
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
   });
 
   // Load Large-Allocation then about:blank load, then back button press should load from bfcache.
   yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
     info("Starting test 4");
     let pid1 = yield getPID(aBrowser);
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     let epc = expectProcessCreated();
 
@@ -220,7 +218,7 @@ add_task(function*() {
     let pid2 = yield getPID(aBrowser);
 
     isnot(pid1, pid2, "PIDs 1 and 2 should not match");
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
 
     yield BrowserTestUtils.browserLoaded(aBrowser);
 
@@ -235,7 +233,7 @@ add_task(function*() {
 
     // We should have been kicked out of the large-allocation process by the
     // load, meaning we're back in a non-large-allocation process.
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     epc = expectProcessCreated();
 
@@ -252,14 +250,14 @@ add_task(function*() {
     isnot(pid1, pid4, "PID 4 shouldn't match PID 1");
     isnot(pid2, pid4, "PID 4 shouldn't match PID 2");
     isnot(pid3, pid4, "PID 4 shouldn't match PID 3");
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
   });
 
   // Two consecutive large-allocation loads should create two processes.
   yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
     info("Starting test 5");
     let pid1 = yield getPID(aBrowser);
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     let ready = Promise.all([expectProcessCreated(),
                              BrowserTestUtils.browserLoaded(aBrowser)]);
@@ -273,7 +271,7 @@ add_task(function*() {
     let pid2 = yield getPID(aBrowser);
 
     isnot(pid1, pid2, "PIDs 1 and 2 should not match");
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
 
     let epc = expectProcessCreated();
 
@@ -290,7 +288,7 @@ add_task(function*() {
     // this was not a fresh process, we'll need to wait for another process.
     // Start listening now.
     epc = expectProcessCreated();
-    if (!(yield getIsFreshProcess(aBrowser))) {
+    if (!(yield getInLAProc(aBrowser))) {
       yield epc;
     } else {
       epc.kill();
@@ -300,14 +298,14 @@ add_task(function*() {
 
     isnot(pid1, pid3, "PIDs 1 and 3 should not match");
     isnot(pid2, pid3, "PIDs 2 and 3 should not match");
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
   });
 
   // Opening a window from the large-allocation window should prevent the process switch.
   yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
     info("Starting test 6");
     let pid1 = yield getPID(aBrowser);
-    is(false, yield getIsFreshProcess(aBrowser));
+    is(false, yield getInLAProc(aBrowser));
 
     let ready = Promise.all([expectProcessCreated(),
                              BrowserTestUtils.browserLoaded(aBrowser)]);
@@ -321,7 +319,7 @@ add_task(function*() {
     let pid2 = yield getPID(aBrowser);
 
     isnot(pid1, pid2, "PIDs 1 and 2 should not match");
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
 
     let stopExpectNoProcess = expectNoProcess();
 
@@ -335,7 +333,7 @@ add_task(function*() {
     let pid3 = yield getPID(aBrowser);
 
     is(pid3, pid2, "PIDs 2 and 3 should match");
-    is(true, yield getIsFreshProcess(aBrowser));
+    is(true, yield getInLAProc(aBrowser));
 
     stopExpectNoProcess();
 
@@ -344,4 +342,45 @@ add_task(function*() {
       this.__newWindow.close();
     });
   });
+
+  yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
+    info("Starting test 7");
+    yield SpecialPowers.pushPrefEnv({
+      set: [
+        ["dom.ipc.processCount.webLargeAllocation", 1]
+      ],
+    });
+
+    // Loading the first Large-Allocation tab should succeed as normal
+    let pid1 = yield getPID(aBrowser);
+    is(false, yield getInLAProc(aBrowser));
+
+    let ready = Promise.all([expectProcessCreated(),
+                             BrowserTestUtils.browserLoaded(aBrowser)]);
+
+    yield ContentTask.spawn(aBrowser, TEST_URI, TEST_URI => {
+      content.document.location = TEST_URI;
+    });
+
+    yield ready;
+
+    let pid2 = yield getPID(aBrowser);
+
+    isnot(pid1, pid2, "PIDs 1 and 2 should not match");
+    is(true, yield getInLAProc(aBrowser));
+
+    yield BrowserTestUtils.withNewTab("about:blank", function*(aBrowser) {
+      // The second one should load in a non-LA proc because the
+      // webLargeAllocation processes have been exhausted.
+      is(false, yield getInLAProc(aBrowser));
+
+      let ready = Promise.all([BrowserTestUtils.browserLoaded(aBrowser)]);
+      yield ContentTask.spawn(aBrowser, TEST_URI, TEST_URI => {
+        content.document.location = TEST_URI;
+      });
+      yield ready;
+
+      is(false, yield getInLAProc(aBrowser));
+    });
+  });
 });