This prevents an issue where if the signal schedules
hwuiTask it will immediately block and go back to sleep due
to mLock still being held.
This costs 10us in thread scheduling ping-ponging bouncing
between hwuiTask and RenderThread
Change-Id: I47595c1bf5736576483a6aa7aada0b1be1e04268
If hwuiTask thread is exited while HWUI renders something,
some tasks can remain unfinished forever.
This can make ANR problem if RenderThread waits this kind of tasks.
According to the current implementation, hwuiTask threads are
exited when HWUI receives trimMemory() callback with level >= 20
and some applications such as SystemUI can receive trimMemory()
with level >= 20 even though they renders something yet.
(For instance, when RecentsActivity in SystemUI is finished,
HWUI receives trimMemory() callback with level >= 20
but SystemUI should still render the status bar and navigation bar.)
This patch prevents the tasks from remaining unfinished and
make the tasks executed immediately if they cannot be added
to their TaskProcessors.
Change-Id: I5bd26439aa5f183b1a7c1ce466362e27554b4d16
This API can be used to run arbitrary tasks on a pool of worker
threads. The number of threads is calculated based on the number
of CPU cores available.
The API is made of 3 classes:
TaskManager
Creates and manages the worker threads.
Task
Describes the work to be done and the type of the output.
A task contains a future used to wait for the worker thread
to be done computing the result of the task.
TaskProcessor
The processor dispatches tasks to the TaskManager and is
responsible for performing the computation required by
each task. A processor will only be asked to process tasks
sent to the manager through the processor.
A typical use case:
class MyTask: Task<MyType>
class MyProcessor: TaskProcessor<MyType>
TaskManager m = new TaskManager();
MyProcessor p = new MyProcessor(m);
MyTask t = new MyTask();
p.add(t);
// Waits until the result is available
MyType result = t->getResult();
Change-Id: I1fe845ba4c49bb0e1b0627ab147f9a861c8e0749
