• Andreas Haas's avatar
    [predictable] Run worker task on the foreground task runner · d6a02c02
    Andreas Haas authored
    On the PredictablePlatform, worker tasks were executed immediately
    instead of posting them in a task queue first. This approach caused
    problems because the execution of the worker task blocked progress of
    the posting task, and the worker task was always executed in the
    context of the posting task, e.g. with an already open HandleScope.
    
    With this CL, worker tasks get posted into the foreground task queue
    of the nullptr isolate instead of executing them immediately.
    The tasks of the nullptr isolate are then executed after a task of
    some other task queue is executed. As the worker tasks are thereby
    executed on the same thread as foreground tasks, the behavior is
    deterministic.
    
    A consequence of this approach is that each pumping the message loop
    of an Isolate may also execute other Isolate's background tasks.
    
    This approach is needed because we don't have a BackgroundTaskRunner but
    merely a CallOnWorkerThread method that doesn't know which Isolate the
    task corresponds to.
    
    R=clemensb@chromium.org, mlippautz@chromium.org
    
    Bug: v8:9670
    Change-Id: I6847ae042146431bc2376d27280be8829f529b95
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2182453
    Commit-Queue: Andreas Haas <ahaas@chromium.org>
    Reviewed-by: 's avatarClemens Backes <clemensb@chromium.org>
    Reviewed-by: 's avatarMichael Lippautz <mlippautz@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#67616}
    d6a02c02
d8.cc 132 KB