Throttle GpuWatchdogThread task posting

Throttle GpuWatchdogThread task posting

The GpuWatchdogThread currently allows multiple tasks to disarm the
watchdog to be posted in a row, only stopping posting when the watchdog
is actually disarmed. This is fairly wasteful, as all but the first
task will just early out. This change adjusts the logic so that we only
post one disarm task, at a time, blocking future disarm tasks until
we have successfully disarmed / rearmed the watchdog.

This change also removes the current "volatile bool", and replaces this with a
base::subtle::Atomic32, which makes the expectations regarding synchronization
more explicit.

BUG=612219
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Committed: https://crrev.com/6971ec6d658d06cace0a6d873608127a99367aee
Cr-Commit-Position: refs/heads/master@{#422549}

[ericrk, 2016-10-03 20:07:02]

Description was changed from

==========
Throttle GpuWatchdogThread task posting

The GpuWatchdogThread currently allows multiple tasks to disarm the
watchdog to be posted in a row, only stopping posting when the watchdog
is actually disarmed. This is fairly wasteful, as all but the first
task will just early out. This change adjusts the logic so that we only
post one disarm task, at a time, blocking future disarm tasks until
we have successfully disarmed / rearmed the watchdog.

This change also removes the current "volatile bool", and replaces this with a
base::subtle::Atomic32, which makes the expectations regarding synchronization
more explicit.

BUG=612219
==========

to

==========
Throttle GpuWatchdogThread task posting

The GpuWatchdogThread currently allows multiple tasks to disarm the
watchdog to be posted in a row, only stopping posting when the watchdog
is actually disarmed. This is fairly wasteful, as all but the first
task will just early out. This change adjusts the logic so that we only
post one disarm task, at a time, blocking future disarm tasks until
we have successfully disarmed / rearmed the watchdog.

This change also removes the current "volatile bool", and replaces this with a
base::subtle::Atomic32, which makes the expectations regarding synchronization
more explicit.

BUG=612219
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
==========

[ericrk, 2016-10-03 20:09:03]

ericrk@chromium.org changed reviewers:
+ danakj@chromium.org, vmiura@chromium.org

[ericrk, 2016-10-03 20:09:09]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-03 20:09:37]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[danakj, 2016-10-03 20:57:50]

LGTM

[vmiura, 2016-10-03 21:06:04]

LGTM

[ericrk, 2016-10-03 21:07:03]

The CQ bit was unchecked by ericrk@chromium.org

[ericrk, 2016-10-03 21:07:10]

The CQ bit was checked by ericrk@chromium.org

[commit-bot: I haz the power, 2016-10-03 21:07:20]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-03 21:52:33]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-03 21:54:51]

Description was changed from

==========
Throttle GpuWatchdogThread task posting

The GpuWatchdogThread currently allows multiple tasks to disarm the
watchdog to be posted in a row, only stopping posting when the watchdog
is actually disarmed. This is fairly wasteful, as all but the first
task will just early out. This change adjusts the logic so that we only
post one disarm task, at a time, blocking future disarm tasks until
we have successfully disarmed / rearmed the watchdog.

This change also removes the current "volatile bool", and replaces this with a
base::subtle::Atomic32, which makes the expectations regarding synchronization
more explicit.

BUG=612219
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
==========

to

==========
Throttle GpuWatchdogThread task posting

The GpuWatchdogThread currently allows multiple tasks to disarm the
watchdog to be posted in a row, only stopping posting when the watchdog
is actually disarmed. This is fairly wasteful, as all but the first
task will just early out. This change adjusts the logic so that we only
post one disarm task, at a time, blocking future disarm tasks until
we have successfully disarmed / rearmed the watchdog.

This change also removes the current "volatile bool", and replaces this with a
base::subtle::Atomic32, which makes the expectations regarding synchronization
more explicit.

BUG=612219
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Committed: https://crrev.com/6971ec6d658d06cace0a6d873608127a99367aee
Cr-Commit-Position: refs/heads/master@{#422549}
==========

[commit-bot: I haz the power, 2016-10-03 21:54:52]

Patchset 1 (id:??) landed as
https://crrev.com/6971ec6d658d06cace0a6d873608127a99367aee
Cr-Commit-Position: refs/heads/master@{#422549}