Wait for concurrent unmapping tasks in GC prologue.

Wait for concurrent unmapping tasks in GC prologue.

BUG=chromium:525372
LOG=n

Committed: https://crrev.com/ebda415e30c1124145f941575ca1d9aee4ed1744
Cr-Commit-Position: refs/heads/master@{#30411}

[Hannes Payer (out of office), 2015-08-27 11:29:27]

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

[Michael Lippautz, 2015-08-27 11:37:42]

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.cc
File src/heap/heap.cc (right):

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.cc#newcode6540
src/heap/heap.cc:6540: if (concurrent_unmaping_tasks_active_ > 0) {
We could make this more general, so that we can start as many unmapping
tasks as we like:

  while(concurrent_unmapping_tasks_active_ > 0) {
    pending_unmap_tasks_semaphore_.Wait();
    concurrent_unmapping_tasks_active_--;
  }

wdyt?

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.h#newcode2379
src/heap/heap.h:2379: unsigned int concurrent_unmaping_tasks_active_;
size_t maybe?

[Hannes Payer (out of office), 2015-08-27 12:34:37]

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.cc
File src/heap/heap.cc (right):

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.cc#newcode6540
src/heap/heap.cc:6540: if (concurrent_unmaping_tasks_active_ > 0) {
On 2015/08/27 11:37:41, Michael Lippautz wrote:
> We could make this more general, so that we can start as many unmapping
> tasks as we like:
> 
>   while(concurrent_unmapping_tasks_active_ > 0) {
>     pending_unmap_tasks_semaphore_.Wait();
>     concurrent_unmapping_tasks_active_--;
>   }
> 
> wdyt?

The intention was to assert if we are waiting for an unexpected number of tasks.
But that may be a bit too static. I will change it to what you proposed. Done.

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.h#newcode2379
src/heap/heap.h:2379: unsigned int concurrent_unmaping_tasks_active_;
On 2015/08/27 11:37:41, Michael Lippautz wrote:
> size_t maybe?

Done.

https://codereview.chromium.org/1320893002/diff/20001/src/heap/heap.cc
File src/heap/heap.cc (right):

https://codereview.chromium.org/1320893002/diff/20001/src/heap/heap.cc#newcod...
src/heap/heap.cc:5764: WaitUntilUnmappingOfFreeChunksCompleted();
We should also wait when we tear down the heap.

[Michael Lippautz, 2015-08-27 12:40:51]

On 2015/08/27 12:34:37, Hannes Payer (slow OOO soon) wrote:
> https://codereview.chromium.org/1320893002/diff/1/src/heap/heap.h#newcode2379
> src/heap/heap.h:2379: unsigned int concurrent_unmaping_tasks_active_;
> On 2015/08/27 11:37:41, Michael Lippautz wrote:
> > size_t maybe?
> 
> Done.
> 

Liar! 

still lgtm

[Hannes Payer (out of office), 2015-08-27 12:47:57]

The CQ bit was checked by hpayer@chromium.org

[Hannes Payer (out of office), 2015-08-27 12:47:58]

The patchset sent to the CQ was uploaded after l-g-t-m from
mlippautz@chromium.org
Link to the patchset: https://codereview.chromium.org/1320893002/#ps60001
(title: " ")

[commit-bot: I haz the power, 2015-08-27 12:48:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1320893002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1320893002/60001

[commit-bot: I haz the power, 2015-08-27 13:28:59]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-08-27 13:29:08]

Patchset 4 (id:??) landed as
https://crrev.com/ebda415e30c1124145f941575ca1d9aee4ed1744
Cr-Commit-Position: refs/heads/master@{#30411}