s390: implement atomic exchange on TF

s390: implement atomic exchange on TF

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com
BUG=

Review-Url: https://codereview.chromium.org/2743803002
Cr-Commit-Position: refs/heads/master@{#43728}
Committed: https://chromium.googlesource.com/v8/v8/+/9598bb9335fa4a6f6431b10787f02ea3859ed8dc

[john.yan, 2017-03-10 01:07:29]

ptal

[JoranSiu, 2017-03-10 04:50:58]

https://codereview.chromium.org/2743803002/diff/20001/src/compiler/s390/code-...
File src/compiler/s390/code-generator-s390.cc (right):

https://codereview.chromium.org/2743803002/diff/20001/src/compiler/s390/code-...
src/compiler/s390/code-generator-s390.cc:2268: __ LoadlW(output,
MemOperand(r1));                                       \
Should this load be in the loop?  i.e.  if another thread changed the mem
contents between this LoadlW and the CS, you might be stuck in the do_cs loop
forever.

[john.yan, 2017-03-10 14:02:26]

On 2017/03/10 04:50:58, JoranSiu wrote:
>
https://codereview.chromium.org/2743803002/diff/20001/src/compiler/s390/code-...
> File src/compiler/s390/code-generator-s390.cc (right):
> 
>
https://codereview.chromium.org/2743803002/diff/20001/src/compiler/s390/code-...
> src/compiler/s390/code-generator-s390.cc:2268: __ LoadlW(output,
> MemOperand(r1));                                       \
> Should this load be in the loop?  i.e.  if another thread changed the mem
> contents between this LoadlW and the CS, you might be stuck in the do_cs loop
> forever.

CS does the load if compare was not equal. (according to doc)

[JoranSiu, 2017-03-10 14:04:23]

On 2017/03/10 14:02:26, john.yan wrote:
> On 2017/03/10 04:50:58, JoranSiu wrote:
> >
>
https://codereview.chromium.org/2743803002/diff/20001/src/compiler/s390/code-...
> > File src/compiler/s390/code-generator-s390.cc (right):
> > 
> >
>
https://codereview.chromium.org/2743803002/diff/20001/src/compiler/s390/code-...
> > src/compiler/s390/code-generator-s390.cc:2268: __ LoadlW(output,
> > MemOperand(r1));                                       \
> > Should this load be in the loop?  i.e.  if another thread changed the mem
> > contents between this LoadlW and the CS, you might be stuck in the do_cs
loop
> > forever.
> 
> CS does the load if compare was not equal. (according to doc)

You are right.  Forgot about that.  lgtm.

[john.yan, 2017-03-10 14:06:23]

Description was changed from

==========
s390: implement atomic exchange on TF

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com
BUG=
==========

to

==========
s390: implement atomic exchange on TF

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com
BUG=
==========

[john.yan, 2017-03-10 14:06:23]

jyan@ca.ibm.com changed reviewers:
+ aseemgarg@chromium.org, binji@chromium.org

[john.yan, 2017-03-10 14:07:31]

On 2017/03/10 14:06:23, john.yan wrote:
> mailto:jyan@ca.ibm.com changed reviewers:
> + mailto:aseemgarg@chromium.org, mailto:binji@chromium.org

ptal the builtin change.
@aseemgarg@chromium.org
@binji@chromium.org

Thanks.

[john.yan, 2017-03-10 14:36:33]

The CQ bit was checked by jyan@ca.ibm.com to run a CQ dry run

[commit-bot: I haz the power, 2017-03-10 14:36:38]

Dry run: 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, 2017-03-10 15:02:27]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-10 15:02:28]

Dry run: This issue passed the CQ dry run.

[john.yan, 2017-03-10 17:55:49]

The CQ bit was checked by jyan@ca.ibm.com to run a CQ dry run

[commit-bot: I haz the power, 2017-03-10 17:55:58]

Dry run: 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, 2017-03-10 18:23:07]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-10 18:23:08]

Dry run: This issue passed the CQ dry run.

[binji, 2017-03-10 18:33:59]

lgtm

[john.yan, 2017-03-10 18:39:14]

The CQ bit was unchecked by jyan@ca.ibm.com

[john.yan, 2017-03-10 18:39:20]

The CQ bit was checked by jyan@ca.ibm.com

[john.yan, 2017-03-10 18:39:20]

The patchset sent to the CQ was uploaded after l-g-t-m from joransiu@ca.ibm.com
Link to the patchset: https://codereview.chromium.org/2743803002/#ps40001
(title: "small fix")

[commit-bot: I haz the power, 2017-03-10 18:39:28]

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, 2017-03-10 18:41:06]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1489171160374560,
"parent_rev": "e61add91c1bccc02b101f21267ce9728d662d250", "commit_rev":
"9598bb9335fa4a6f6431b10787f02ea3859ed8dc"}

[commit-bot: I haz the power, 2017-03-10 18:41:12]

Description was changed from

==========
s390: implement atomic exchange on TF

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com
BUG=
==========

to

==========
s390: implement atomic exchange on TF

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com
BUG=

Review-Url: https://codereview.chromium.org/2743803002
Cr-Commit-Position: refs/heads/master@{#43728}
Committed:
https://chromium.googlesource.com/v8/v8/+/9598bb9335fa4a6f6431b10787f02ea3859...
==========

[commit-bot: I haz the power, 2017-03-10 18:41:13]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/v8/v8/+/9598bb9335fa4a6f6431b10787f02ea3859...