Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 301 insertions, 0 deletions

diff --git a/ipc/glue/IdleSchedulerParent.cpp b/ipc/glue/IdleSchedulerParent.cpp
new file mode 100644
index 0000000000..292f75eb01
--- /dev/null
+++ b/ipc/glue/IdleSchedulerParent.cpp
@@ -0,0 +1,301 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "mozilla/StaticPrefs_page_load.h"
+#include "mozilla/Unused.h"
+#include "mozilla/ipc/IdleSchedulerParent.h"
+#include "nsSystemInfo.h"
+#include "nsThreadUtils.h"
+#include "nsITimer.h"
+
+namespace mozilla {
+namespace ipc {
+
+base::SharedMemory* IdleSchedulerParent::sActiveChildCounter = nullptr;
+std::bitset<NS_IDLE_SCHEDULER_COUNTER_ARRAY_LENGHT>
+    IdleSchedulerParent::sInUseChildCounters;
+LinkedList<IdleSchedulerParent> IdleSchedulerParent::sWaitingForIdle;
+Atomic<int32_t> IdleSchedulerParent::sMaxConcurrentIdleTasksInChildProcesses(
+    -1);
+uint32_t IdleSchedulerParent::sChildProcessesRunningPrioritizedOperation = 0;
+uint32_t IdleSchedulerParent::sChildProcessesAlive = 0;
+nsITimer* IdleSchedulerParent::sStarvationPreventer = nullptr;
+
+IdleSchedulerParent::IdleSchedulerParent() {
+  sChildProcessesAlive++;
+
+  if (sMaxConcurrentIdleTasksInChildProcesses == -1) {
+    // nsISystemInfo can be initialized only on the main thread.
+    // While waiting for the real logical core count behave as if there was just
+    // one core.
+    sMaxConcurrentIdleTasksInChildProcesses = 1;
+    nsCOMPtr<nsIThread> thread = do_GetCurrentThread();
+    nsCOMPtr<nsIRunnable> runnable =
+        NS_NewRunnableFunction("cpucount getter", [thread]() {
+          // Always pretend that there is at least one core for child processes.
+          // If there are multiple logical cores, reserve one for the parent
+          // process and for the non-main threads.
+          ProcessInfo processInfo = {};
+          if (NS_SUCCEEDED(CollectProcessInfo(processInfo)) &&
+              processInfo.cpuCount > 1) {
+            // On one and two processor (or hardware thread) systems this will
+            // allow one concurrent idle task.
+            sMaxConcurrentIdleTasksInChildProcesses =
+                std::max(processInfo.cpuCount - 1, 1);
+            // We have a new cpu count, reschedule idle scheduler.
+            nsCOMPtr<nsIRunnable> runnable =
+                NS_NewRunnableFunction("IdleSchedulerParent::Schedule", []() {
+                  if (sActiveChildCounter && sActiveChildCounter->memory()) {
+                    static_cast<Atomic<int32_t>*>(sActiveChildCounter->memory())
+                        [NS_IDLE_SCHEDULER_INDEX_OF_CPU_COUNTER] =
+                            static_cast<int32_t>(
+                                sMaxConcurrentIdleTasksInChildProcesses);
+                  }
+                  IdleSchedulerParent::Schedule(nullptr);
+                });
+            thread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+          }
+        });
+    NS_DispatchBackgroundTask(runnable.forget(), NS_DISPATCH_EVENT_MAY_BLOCK);
+  }
+}
+
+IdleSchedulerParent::~IdleSchedulerParent() {
+  // We can't know if an active process just crashed, so we just always expect
+  // that is the case.
+  if (mChildId) {
+    sInUseChildCounters[mChildId] = false;
+    if (sActiveChildCounter && sActiveChildCounter->memory() &&
+        static_cast<Atomic<int32_t>*>(
+            sActiveChildCounter->memory())[mChildId]) {
+      --static_cast<Atomic<int32_t>*>(
+          sActiveChildCounter
+              ->memory())[NS_IDLE_SCHEDULER_INDEX_OF_ACTIVITY_COUNTER];
+      static_cast<Atomic<int32_t>*>(sActiveChildCounter->memory())[mChildId] =
+          0;
+    }
+  }
+
+  if (mRunningPrioritizedOperation) {
+    --sChildProcessesRunningPrioritizedOperation;
+  }
+
+  if (isInList()) {
+    remove();
+  }
+
+  MOZ_ASSERT(sChildProcessesAlive > 0);
+  sChildProcessesAlive--;
+  if (sChildProcessesAlive == 0) {
+    MOZ_ASSERT(sWaitingForIdle.isEmpty());
+    delete sActiveChildCounter;
+    sActiveChildCounter = nullptr;
+
+    if (sStarvationPreventer) {
+      sStarvationPreventer->Cancel();
+      NS_RELEASE(sStarvationPreventer);
+    }
+  }
+
+  Schedule(nullptr);
+}
+
+IPCResult IdleSchedulerParent::RecvInitForIdleUse(
+    InitForIdleUseResolver&& aResolve) {
+  // This must already be non-zero, if it is zero then the cleanup code for the
+  // shared memory (initialised below) will never run.  The invariant is that if
+  // the shared memory is initialsed, then this is non-zero.
+  MOZ_ASSERT(sChildProcessesAlive > 0);
+
+  MOZ_ASSERT(IsNotDoingIdleTask());
+
+  // Create a shared memory object which is shared across all the relevant
+  // processes.
+  if (!sActiveChildCounter) {
+    sActiveChildCounter = new base::SharedMemory();
+    size_t shmemSize = NS_IDLE_SCHEDULER_COUNTER_ARRAY_LENGHT * sizeof(int32_t);
+    if (sActiveChildCounter->Create(shmemSize) &&
+        sActiveChildCounter->Map(shmemSize)) {
+      memset(sActiveChildCounter->memory(), 0, shmemSize);
+      sInUseChildCounters[NS_IDLE_SCHEDULER_INDEX_OF_ACTIVITY_COUNTER] = true;
+      sInUseChildCounters[NS_IDLE_SCHEDULER_INDEX_OF_CPU_COUNTER] = true;
+      static_cast<Atomic<int32_t>*>(
+          sActiveChildCounter
+              ->memory())[NS_IDLE_SCHEDULER_INDEX_OF_CPU_COUNTER] =
+          static_cast<int32_t>(sMaxConcurrentIdleTasksInChildProcesses);
+    } else {
+      delete sActiveChildCounter;
+      sActiveChildCounter = nullptr;
+    }
+  }
+  Maybe<SharedMemoryHandle> activeCounter;
+  SharedMemoryHandle handle;
+  if (sActiveChildCounter &&
+      sActiveChildCounter->ShareToProcess(OtherPid(), &handle)) {
+    activeCounter.emplace(handle);
+  }
+
+  uint32_t unusedId = 0;
+  for (uint32_t i = 0; i < NS_IDLE_SCHEDULER_COUNTER_ARRAY_LENGHT; ++i) {
+    if (!sInUseChildCounters[i]) {
+      sInUseChildCounters[i] = true;
+      unusedId = i;
+      break;
+    }
+  }
+
+  // If there wasn't an empty item, we'll fallback to 0.
+  mChildId = unusedId;
+
+  aResolve(Tuple<const mozilla::Maybe<SharedMemoryHandle>&, const uint32_t&>(
+      activeCounter, mChildId));
+  return IPC_OK();
+}
+
+IPCResult IdleSchedulerParent::RecvRequestIdleTime(uint64_t aId,
+                                                   TimeDuration aBudget) {
+  MOZ_ASSERT(aBudget);
+  MOZ_ASSERT(IsNotDoingIdleTask());
+
+  mCurrentRequestId = aId;
+  mRequestedIdleBudget = aBudget;
+
+  sWaitingForIdle.insertBack(this);
+
+  Schedule(this);
+  return IPC_OK();
+}
+
+IPCResult IdleSchedulerParent::RecvIdleTimeUsed(uint64_t aId) {
+  // The client can either signal that they've used the idle time or they're
+  // canceling the request.  We cannot use a seperate cancel message because it
+  // could arrive after the parent has granted the request.
+  MOZ_ASSERT(IsWaitingForIdle() || IsDoingIdleTask());
+
+  // The parent process will always know the ID of the current request (since
+  // the IPC channel is reliable).  The IDs are provided so that the client can
+  // check them (it's possible for the client to race ahead of the server).
+  MOZ_ASSERT(mCurrentRequestId == aId);
+
+  if (IsWaitingForIdle()) {
+    remove();
+  }
+  mRequestedIdleBudget = TimeDuration();
+  Schedule(nullptr);
+  return IPC_OK();
+}
+
+IPCResult IdleSchedulerParent::RecvSchedule() {
+  Schedule(nullptr);
+  return IPC_OK();
+}
+
+IPCResult IdleSchedulerParent::RecvRunningPrioritizedOperation() {
+  ++mRunningPrioritizedOperation;
+  if (mRunningPrioritizedOperation == 1) {
+    ++sChildProcessesRunningPrioritizedOperation;
+  }
+  return IPC_OK();
+}
+
+IPCResult IdleSchedulerParent::RecvPrioritizedOperationDone() {
+  MOZ_ASSERT(mRunningPrioritizedOperation);
+
+  --mRunningPrioritizedOperation;
+  if (mRunningPrioritizedOperation == 0) {
+    --sChildProcessesRunningPrioritizedOperation;
+    Schedule(nullptr);
+  }
+  return IPC_OK();
+}
+
+int32_t IdleSchedulerParent::ActiveCount() {
+  if (sActiveChildCounter) {
+    return (static_cast<Atomic<int32_t>*>(
+        sActiveChildCounter
+            ->memory())[NS_IDLE_SCHEDULER_INDEX_OF_ACTIVITY_COUNTER]);
+  }
+  return 0;
+}
+
+bool IdleSchedulerParent::HasSpareCycles(int32_t aActiveCount) {
+  // We can run a new task if we have a spare core.  If we're running a
+  // prioritised operation we halve the number of regular spare cores.
+  //
+  // sMaxConcurrentIdleTasksInChildProcesses will always be >0 so on 1 and 2
+  // core systems this will allow 1 idle tasks (0 if running a prioritized
+  // operation).
+  MOZ_ASSERT(sMaxConcurrentIdleTasksInChildProcesses > 0);
+  return sChildProcessesRunningPrioritizedOperation
+             ? sMaxConcurrentIdleTasksInChildProcesses / 2 > aActiveCount
+             : sMaxConcurrentIdleTasksInChildProcesses > aActiveCount;
+}
+
+void IdleSchedulerParent::SendIdleTime() {
+  // We would assert that IsWaiting() except after removing the task from it's
+  // list this will return false.  Instead check IsDoingIdleTask()
+  MOZ_ASSERT(IsDoingIdleTask());
+  Unused << SendIdleTime(mCurrentRequestId, mRequestedIdleBudget);
+}
+
+void IdleSchedulerParent::Schedule(IdleSchedulerParent* aRequester) {
+  // Tasks won't update the active count until after they receive their message
+  // and start to run, so make a copy of it here and increment it for every task
+  // we schedule. It will become an estimate of how many tasks will be active
+  // shortly.
+  int32_t activeCount = ActiveCount();
+
+  if (aRequester && aRequester->mRunningPrioritizedOperation) {
+    // If the requester is prioritized, just let it run itself.
+    if (aRequester->isInList()) {
+      aRequester->remove();
+    }
+    aRequester->SendIdleTime();
+    activeCount++;
+  }
+
+  while (!sWaitingForIdle.isEmpty() && HasSpareCycles(activeCount)) {
+    // We can run an idle task.
+    RefPtr<IdleSchedulerParent> idleRequester = sWaitingForIdle.popFirst();
+    idleRequester->SendIdleTime();
+    activeCount++;
+  }
+
+  if (!sWaitingForIdle.isEmpty()) {
+    EnsureStarvationTimer();
+  }
+}
+
+void IdleSchedulerParent::EnsureStarvationTimer() {
+  // Even though idle runnables aren't really guaranteed to get run ever (which
+  // is why most of them have the timer fallback), try to not let any child
+  // process' idle handling to starve forever in case other processes are busy
+  if (!sStarvationPreventer) {
+    // Reuse StaticPrefs::page_load_deprioritization_period(), since that
+    // is used on child side when deciding the minimum idle period.
+    NS_NewTimerWithFuncCallback(
+        &sStarvationPreventer, StarvationCallback, nullptr,
+        StaticPrefs::page_load_deprioritization_period(),
+        nsITimer::TYPE_ONE_SHOT_LOW_PRIORITY, "StarvationCallback");
+  }
+}
+
+void IdleSchedulerParent::StarvationCallback(nsITimer* aTimer, void* aData) {
+  if (!sWaitingForIdle.isEmpty()) {
+    RefPtr<IdleSchedulerParent> first = sWaitingForIdle.getFirst();
+    // Treat the first process waiting for idle time as running prioritized
+    // operation so that it gets run.
+    ++first->mRunningPrioritizedOperation;
+    ++sChildProcessesRunningPrioritizedOperation;
+    Schedule(first);
+    --first->mRunningPrioritizedOperation;
+    --sChildProcessesRunningPrioritizedOperation;
+  }
+  NS_RELEASE(sStarvationPreventer);
+}
+
+}  // namespace ipc
+}  // namespace mozilla