[heap] Make slot set state and operations atomic.

[heap] Make slot set state and operations atomic.

Here we only change the type of the slot set fields to atomic values and use CAS to change the state. There is no change in behavior or semantics of the slot set.

BUG=chromium:648568
Committed: https://crrev.com/e05e735a8ab39b5f871c9356b993d52d562e7fee
Cr-Commit-Position: refs/heads/master@{#39557}

[Hannes Payer (out of office), 2016-09-20 12:12:39]

Description was changed from

==========
[heap] Make slot set state and operations atomic.

BUG=chromium:648568
==========

to

==========
[heap] Make slot set state and operations atomic.

Here we only change the type of the slot set fields to atomic values and use CAS
to change the state. There is no change in behavior or semantics of the slot
set.

BUG=chromium:648568
==========

[Hannes Payer (out of office), 2016-09-20 12:12:39]

hpayer@chromium.org changed reviewers:
+ ulan@chromium.org

[ulan, 2016-09-20 12:33:02]

https://codereview.chromium.org/2353553003/diff/20001/src/base/atomic-utils.h
File src/base/atomic-utils.h (right):

https://codereview.chromium.org/2353553003/diff/20001/src/base/atomic-utils.h...
src/base/atomic-utils.h:75: V8_INLINE void SetBits(T bits, int mask) {
mask also should be T

https://codereview.chromium.org/2353553003/diff/20001/src/base/atomic-utils.h...
src/base/atomic-utils.h:85: V8_INLINE void SetBit(int bit) { SetBits(1 << bit, 1
<< bit); }
How about static_cast<T>(1) << bit to avoid potential overflows?

https://codereview.chromium.org/2353553003/diff/20001/src/heap/slot-set.h
File src/heap/slot-set.h (right):

https://codereview.chromium.org/2353553003/diff/20001/src/heap/slot-set.h#new...
src/heap/slot-set.h:41: void Insert(int slot_offset) {
Could you please add a comment that this method should be called only from the
main thread?

https://codereview.chromium.org/2353553003/diff/20001/src/heap/slot-set.h#new...
src/heap/slot-set.h:166: current_bucket[i].SetValue(new_cell);
As discussed offline, we should use CAS here.

[Hannes Payer (out of office), 2016-09-20 13:51:29]

https://codereview.chromium.org/2353553003/diff/20001/src/base/atomic-utils.h
File src/base/atomic-utils.h (right):

https://codereview.chromium.org/2353553003/diff/20001/src/base/atomic-utils.h...
src/base/atomic-utils.h:75: V8_INLINE void SetBits(T bits, int mask) {
On 2016/09/20 12:33:02, ulan wrote:
> mask also should be T

Done.

https://codereview.chromium.org/2353553003/diff/20001/src/base/atomic-utils.h...
src/base/atomic-utils.h:85: V8_INLINE void SetBit(int bit) { SetBits(1 << bit, 1
<< bit); }
On 2016/09/20 12:33:02, ulan wrote:
> How about static_cast<T>(1) << bit to avoid potential overflows?

Done.

https://codereview.chromium.org/2353553003/diff/20001/src/heap/slot-set.h
File src/heap/slot-set.h (right):

https://codereview.chromium.org/2353553003/diff/20001/src/heap/slot-set.h#new...
src/heap/slot-set.h:41: void Insert(int slot_offset) {
On 2016/09/20 12:33:02, ulan wrote:
> Could you please add a comment that this method should be called only from the
> main thread?

Done.

https://codereview.chromium.org/2353553003/diff/20001/src/heap/slot-set.h#new...
src/heap/slot-set.h:166: current_bucket[i].SetValue(new_cell);
On 2016/09/20 12:33:02, ulan wrote:
> As discussed offline, we should use CAS here.

Done.

[Hannes Payer (out of office), 2016-09-20 13:51:35]

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

[commit-bot: I haz the power, 2016-09-20 13:51:43]

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

[ulan, 2016-09-20 13:55:48]

lgtm!

[Hannes Payer (out of office), 2016-09-20 14:02:05]

The CQ bit was unchecked by hpayer@chromium.org

[Hannes Payer (out of office), 2016-09-20 14:02:08]

The CQ bit was checked by hpayer@chromium.org

[commit-bot: I haz the power, 2016-09-20 14:02:13]

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, 2016-09-20 14:58:42]

Description was changed from

==========
[heap] Make slot set state and operations atomic.

Here we only change the type of the slot set fields to atomic values and use CAS
to change the state. There is no change in behavior or semantics of the slot
set.

BUG=chromium:648568
==========

to

==========
[heap] Make slot set state and operations atomic.

Here we only change the type of the slot set fields to atomic values and use CAS
to change the state. There is no change in behavior or semantics of the slot
set.

BUG=chromium:648568
==========

[commit-bot: I haz the power, 2016-09-20 14:58:43]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-09-20 14:59:04]

Description was changed from

==========
[heap] Make slot set state and operations atomic.

Here we only change the type of the slot set fields to atomic values and use CAS
to change the state. There is no change in behavior or semantics of the slot
set.

BUG=chromium:648568
==========

to

==========
[heap] Make slot set state and operations atomic.

Here we only change the type of the slot set fields to atomic values and use CAS
to change the state. There is no change in behavior or semantics of the slot
set.

BUG=chromium:648568

Committed: https://crrev.com/e05e735a8ab39b5f871c9356b993d52d562e7fee
Cr-Commit-Position: refs/heads/master@{#39557}
==========

[commit-bot: I haz the power, 2016-09-20 14:59:04]

Patchset 3 (id:??) landed as
https://crrev.com/e05e735a8ab39b5f871c9356b993d52d562e7fee
Cr-Commit-Position: refs/heads/master@{#39557}