1. Add code to grow the heap instead of collecting garbage in Heap::AllocateOld when allocation is …

1. Add code to grow the heap instead of collecting garbage in Heap::AllocateOld when allocation is done by a non mutator thread which is at a safepoint. Garbage collection is triggered after the safepoint is done.

2. Add code to avoid multiple garbage collection requests on different threads to sync up and allow only one request to proceed at a time, other requests wait for this garbage collection request to be done and then proceed to allocation once the request is done.

R=iposva@google.com

Committed: https://github.com/dart-lang/sdk/commit/a0fedf387973d19db2cf0eecb3096fe80c970c8d

[siva, 2016-01-06 20:09:57]

Description was changed from

==========
1. Add code to grow the heap instead of collecting garbage in Heap::AllocateOld
when allocation is done by non mutator thread which is at a safepoint. garbage
collection is triggerred after the safepoint is done.

2. Add code to avoid multiple garbage collection requests on different threads
to sync up and allow only one request to proceed at a time, other requests wait
for this garbage collection request to be done and then proceed to allocation
once the request is done.
==========

to

==========
1. Add code to grow the heap instead of collecting garbage in Heap::AllocateOld
when allocation is done by a non mutator thread which is at a safepoint. Garbage
collection is triggered after the safepoint is done.

2. Add code to avoid multiple garbage collection requests on different threads
to sync up and allow only one request to proceed at a time, other requests wait
for this garbage collection request to be done and then proceed to allocation
once the request is done.
==========

[siva, 2016-01-06 20:32:46]

asiva@google.com changed reviewers:
+ iposva@google.com

[Ivan Posva, 2016-01-11 06:14:10]

LGTM -ip

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/compiler.cc
File runtime/vm/compiler.cc (right):

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/compiler.cc#...
runtime/vm/compiler.cc:1064: // We do not Garbage collect during this stage and
allow the
// Do not allow garbage collection during this stage and instead allow the heap
to grow.

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/heap.cc
File runtime/vm/heap.cc (right):

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/heap.cc#newc...
runtime/vm/heap.cc:83: CollectGarbage(kNew);
Please add a comment that the CollectGarbage(kNew) here might actually end up
"reusing" a collection spawned from a different thread and will be racing to
allocate the memory requested with other threads being released after the
collection.

Not sure how to easily break this race here, although it is very unlikely.

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/heap.cc#newc...
runtime/vm/heap.cc:132: // Force growth before attempting a synchronous GC.
a -> another

[siva, 2016-01-11 18:27:47]

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/compiler.cc
File runtime/vm/compiler.cc (right):

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/compiler.cc#...
runtime/vm/compiler.cc:1064: // We do not Garbage collect during this stage and
allow the
On 2016/01/11 06:14:09, Ivan Posva wrote:
> // Do not allow garbage collection during this stage and instead allow the
heap
> to grow.

Done.

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/heap.cc
File runtime/vm/heap.cc (right):

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/heap.cc#newc...
runtime/vm/heap.cc:83: CollectGarbage(kNew);
On 2016/01/11 06:14:09, Ivan Posva wrote:
> Please add a comment that the CollectGarbage(kNew) here might actually end up
> "reusing" a collection spawned from a different thread and will be racing to
> allocate the memory requested with other threads being released after the
> collection.
> 
> Not sure how to easily break this race here, although it is very unlikely.


Added a comment.

If a new space collection happened it is likely that space will be available for
all the threads and if we are at the edge then it probably makes sense to
allocate in old.

https://codereview.chromium.org/1562853003/diff/20001/runtime/vm/heap.cc#newc...
runtime/vm/heap.cc:132: // Force growth before attempting a synchronous GC.
On 2016/01/11 06:14:09, Ivan Posva wrote:
> a -> another

Done.

[siva, 2016-01-11 19:01:02]

Description was changed from

==========
1. Add code to grow the heap instead of collecting garbage in Heap::AllocateOld
when allocation is done by a non mutator thread which is at a safepoint. Garbage
collection is triggered after the safepoint is done.

2. Add code to avoid multiple garbage collection requests on different threads
to sync up and allow only one request to proceed at a time, other requests wait
for this garbage collection request to be done and then proceed to allocation
once the request is done.
==========

to

==========
1. Add code to grow the heap instead of collecting garbage in Heap::AllocateOld
when allocation is done by a non mutator thread which is at a safepoint. Garbage
collection is triggered after the safepoint is done.

2. Add code to avoid multiple garbage collection requests on different threads
to sync up and allow only one request to proceed at a time, other requests wait
for this garbage collection request to be done and then proceed to allocation
once the request is done.

R=iposva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/a0fedf387973d19db2cf0eecb3096fe80c970c8d
==========

[siva, 2016-01-11 19:01:03]

Committed patchset #3 (id:40001) manually as
a0fedf387973d19db2cf0eecb3096fe80c970c8d (presubmit successful).