debian-packages/vibe-core
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Fix TaskScheduler.waitAndProcess to not block if any tasks were resumed.

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In situations where no events were involved in an multi-task scenario, the old behavior could lead to the process to starve or hang until an event arrived.
This commit is contained in:
Sönke Ludwig 2016-12-10 14:13:44 +01:00
parent df69c86bd4
commit bf2edc7fb2
2 changed files with 20 additions and 8 deletions
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2
source/vibe/core/core.d
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@ -1131,7 +1131,7 @@ package(vibe) void performIdleProcessing()
again = s_idleHandler(); again = s_idleHandler();
else again = false; else again = false;
again = (s_scheduler.schedule() || again) && !getExitFlag(); again = (s_scheduler.schedule() == ScheduleStatus.busy || again) && !getExitFlag();
if (again) { if (again) {
auto er = eventDriver.core.processEvents(0.seconds); auto er = eventDriver.core.processEvents(0.seconds);

26
source/vibe/core/task.d
View file

@ -57,7 +57,6 @@ struct Task {
if (!fiber) return Task.init; if (!fiber) return Task.init;
auto tfiber = cast(TaskFiber)fiber; auto tfiber = cast(TaskFiber)fiber;
assert(tfiber !is null, "Invalid or null fiber used to construct Task handle."); assert(tfiber !is null, "Invalid or null fiber used to construct Task handle.");
if (!tfiber.m_running) return Task.init;
return () @trusted { return Task(tfiber, tfiber.m_taskCounter); } (); return () @trusted { return Task(tfiber, tfiber.m_taskCounter); } ();
} }
@ -104,6 +103,7 @@ struct Task {
md.put(nativeToLittleEndian(() @trusted { return cast(size_t)cast(void*)m_fiber; } ())); md.put(nativeToLittleEndian(() @trusted { return cast(size_t)cast(void*)m_fiber; } ()));
md.put(nativeToLittleEndian(m_taskCounter)); md.put(nativeToLittleEndian(m_taskCounter));
Base64.encode(md.finish()[0 .. 3], dst); Base64.encode(md.finish()[0 .. 3], dst);
if (!this.running) dst.put("-fin");
} }
bool opEquals(in ref Task other) const @safe nothrow { return m_fiber is other.m_fiber && m_taskCounter == other.m_taskCounter; } bool opEquals(in ref Task other) const @safe nothrow { return m_fiber is other.m_fiber && m_taskCounter == other.m_taskCounter; }
@ -458,8 +458,10 @@ final package class TaskFiber : Fiber {
package void handleInterrupt() package void handleInterrupt()
@safe { @safe {
if (m_interrupt) if (m_interrupt) {
m_interrupt = false;
throw new InterruptException; throw new InterruptException;
}
} }
} }
@ -551,7 +553,7 @@ package struct TaskScheduler {
bool any_events = false; bool any_events = false;
while (true) { while (true) {
// process pending tasks // process pending tasks
schedule(); bool any_tasks_processed = schedule() != ScheduleStatus.idle;
logTrace("Processing pending events..."); logTrace("Processing pending events...");
ExitReason er = eventDriver.core.processEvents(0.seconds); ExitReason er = eventDriver.core.processEvents(0.seconds);
@ -565,7 +567,7 @@ package struct TaskScheduler {
break; break;
case ExitReason.timeout: case ExitReason.timeout:
if (!scheduledTaskCount) if (!scheduledTaskCount)
return any_events ? ExitReason.idle : ExitReason.timeout; return any_events || any_tasks_processed ? ExitReason.idle : ExitReason.timeout;
break; break;
case ExitReason.idle: case ExitReason.idle:
any_events = true; any_events = true;
@ -686,8 +688,12 @@ package struct TaskScheduler {
Returns: Returns:
Returns `true` $(I iff) there are more tasks left to process. Returns `true` $(I iff) there are more tasks left to process.
*/ */
bool schedule() ScheduleStatus schedule()
{ {
if (m_taskQueue.empty)
return ScheduleStatus.idle;
if (!m_markerTask) m_markerTask = new TaskFiber; // TODO: avoid allocating an actual task here! if (!m_markerTask) m_markerTask = new TaskFiber; // TODO: avoid allocating an actual task here!
assert(Task.getThis() == Task.init, "TaskScheduler.schedule() may not be called from a task!"); assert(Task.getThis() == Task.init, "TaskScheduler.schedule() may not be called from a task!");
@ -703,13 +709,13 @@ package struct TaskScheduler {
resumeTask(t.task); resumeTask(t.task);
assert(!m_taskQueue.empty, "Marker task got removed from tasks queue!?"); assert(!m_taskQueue.empty, "Marker task got removed from tasks queue!?");
if (m_taskQueue.empty) return false; // handle gracefully in release mode if (m_taskQueue.empty) return ScheduleStatus.idle; // handle gracefully in release mode
} }
// remove marker task // remove marker task
m_taskQueue.popFront(); m_taskQueue.popFront();
return !m_taskQueue.empty; return m_taskQueue.empty ? ScheduleStatus.allProcessed : ScheduleStatus.busy;
} }
/// Resumes execution of a yielded task. /// Resumes execution of a yielded task.
@ -740,6 +746,12 @@ package struct TaskScheduler {
} }
} }
package enum ScheduleStatus {
idle,
allProcessed,
busy
}
private struct TaskFiberQueue { private struct TaskFiberQueue {
@safe nothrow: @safe nothrow: