[heap] New API for increasing the heap limit for debugging.

[heap] New API for increasing the heap limit for debugging.

BUG=chromium:675911
Review-Url: https://codereview.chromium.org/2593043002
Cr-Commit-Position: refs/heads/master@{#41957}
Committed: https://chromium.googlesource.com/v8/v8/+/d6c66dbce610713fc96edc94e6a7036a7ef6c695

[ulan, 2016-12-21 17:14:18]

ulan@chromium.org changed reviewers:
+ hpayer@chromium.org, kozyatinskiy@chromium.org, mlippautz@chromium.org

[ulan, 2016-12-21 17:14:18]

PTAL. Open to suggestions for constants.

[Hannes Payer (out of office), 2016-12-22 11:50:29]

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h#newcode958
src/heap/heap.h:958: Min(max_limit, max_old_generation_size_ *
kDebugHeapSizeFactor));
Isn't the requirement on 32-bit to stay within 2G to support dev tools?

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h#newcode963
src/heap/heap.h:963: size_t min_limit = SizeOfObjects() + SizeOfObjects() / 4;
If the restoring of the initial max_old_generation_size_ fails, we are going to
run now with a larger max size. Is that a problem?

[ulan, 2016-12-22 14:04:51]

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h#newcode958
src/heap/heap.h:958: Min(max_limit, max_old_generation_size_ *
kDebugHeapSizeFactor));
On 2016/12/22 11:50:29, Hannes Payer wrote:
> Isn't the requirement on 32-bit to stay within 2G to support dev tools?

Yes, max_limit is 1GB on 32-bit.

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h#newcode963
src/heap/heap.h:963: size_t min_limit = SizeOfObjects() + SizeOfObjects() / 4;
On 2016/12/22 11:50:29, Hannes Payer wrote:
> If the restoring of the initial max_old_generation_size_ fails, we are going
to
> run now with a larger max size. Is that a problem?

Yep, we have no choice there. It is probably ok, because the increase is
requested by the user in devtools.

[Hannes Payer (out of office), 2016-12-23 07:49:56]

lgtm

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h#newcode963
src/heap/heap.h:963: size_t min_limit = SizeOfObjects() + SizeOfObjects() / 4;
On 2016/12/22 14:04:51, ulan wrote:
> On 2016/12/22 11:50:29, Hannes Payer wrote:
> > If the restoring of the initial max_old_generation_size_ fails, we are going
> to
> > run now with a larger max size. Is that a problem?
> 
> Yep, we have no choice there. It is probably ok, because the increase is
> requested by the user in devtools.

We could try to set it at the end of a full gc and retry until we reached the
original maximum. Do you think that makes sense?

[ulan, 2016-12-27 12:41:35]

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/2593043002/diff/1/src/heap/heap.h#newcode963
src/heap/heap.h:963: size_t min_limit = SizeOfObjects() + SizeOfObjects() / 4;
On 2016/12/23 07:49:56, Hannes Payer wrote:
> On 2016/12/22 14:04:51, ulan wrote:
> > On 2016/12/22 11:50:29, Hannes Payer wrote:
> > > If the restoring of the initial max_old_generation_size_ fails, we are
going
> > to
> > > run now with a larger max size. Is that a problem?
> > 
> > Yep, we have no choice there. It is probably ok, because the increase is
> > requested by the user in devtools.
> 
> We could try to set it at the end of a full gc and retry until we reached the
> original maximum. Do you think that makes sense?
It makes sense as mitigation, but there is no guarantee that GC can reduce heap
to the original maximum. Let's for now keep it simple :)

[ulan, 2016-12-27 12:41:38]

The CQ bit was checked by ulan@chromium.org

[ulan, 2016-12-27 12:41:39]

The patchset sent to the CQ was uploaded after l-g-t-m from hpayer@chromium.org
Link to the patchset: https://codereview.chromium.org/2593043002/#ps40001
(title: "add test")

[commit-bot: I haz the power, 2016-12-27 12:41:42]

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, 2016-12-27 13:29:59]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1482842498837440,
"parent_rev": "47e1cc4685af88815b3fa6bf7648544bab7d8d18", "commit_rev":
"d6c66dbce610713fc96edc94e6a7036a7ef6c695"}

[commit-bot: I haz the power, 2016-12-27 13:30:04]

Description was changed from

==========
[heap] New API for increasing the heap limit for debugging.

BUG=chromium:675911
==========

to

==========
[heap] New API for increasing the heap limit for debugging.

BUG=chromium:675911

Review-Url: https://codereview.chromium.org/2593043002
Cr-Commit-Position: refs/heads/master@{#41957}
Committed:
https://chromium.googlesource.com/v8/v8/+/d6c66dbce610713fc96edc94e6a7036a7ef...
==========

[commit-bot: I haz the power, 2016-12-27 13:30:05]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/v8/v8/+/d6c66dbce610713fc96edc94e6a7036a7ef...