Separate mutex for megamorphic cache tables lookup in the background compiler.

Separate mutex for megamorphic cache tables lookup in the background compiler.

Lookup and updates to the megamorphic cache tables should be protected by a
separate mutex - using isolate->mutex() can cause a dead lock if the background
compiler holds this lock while it's being stopped by the mutator thread.

BUG=#26808
R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/858ee49cea3e3cc30f1b444aa49a163de7eb1bf9

[Florian Schneider, 2016-07-01 17:11:53]

Description was changed from

==========
Separate mutex for megamorphic cache tables lookup in the background compiler.

Lookup and updates to the megamorphic cache tables should be protected by a
separate mutex - using isolate->mutex() can cause a dead lock if the background
compiler holds this lock while it's being stopped by the mutator thread.

BUG=
==========

to

==========
Separate mutex for megamorphic cache tables lookup in the background compiler.

Lookup and updates to the megamorphic cache tables should be protected by a
separate mutex - using isolate->mutex() can cause a dead lock if the background
compiler holds this lock while it's being stopped by the mutator thread.

BUG=#26808
==========

[Florian Schneider, 2016-07-01 17:12:01]

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

[Cutch, 2016-07-01 17:16:17]

johnmccutchan@google.com changed reviewers:
+ johnmccutchan@google.com

[Cutch, 2016-07-01 17:16:18]

DBC

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.cc#newco...
runtime/vm/isolate.cc:800: lookup_mutex_(new Mutex()),
where is this mutex deleted?

[siva, 2016-07-01 17:39:29]

lgtm

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.cc#newco...
runtime/vm/isolate.cc:800: lookup_mutex_(new Mutex()),
On 2016/07/01 17:16:18, Cutch wrote:
> where is this mutex deleted?

Yes we need to delete it in the destructor.

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.h
File runtime/vm/isolate.h (right):

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.h#newcod...
runtime/vm/isolate.h:721: Mutex* lookup_mutex_;  // Protects megamorphic table
lookup.
can we call it megamorphic_lookup_mutex_;
so that it is more clear and people don't use it for other lookups.

[Florian Schneider, 2016-07-01 19:31:58]

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.cc#newco...
runtime/vm/isolate.cc:800: lookup_mutex_(new Mutex()),
On 2016/07/01 17:39:29, siva wrote:
> On 2016/07/01 17:16:18, Cutch wrote:
> > where is this mutex deleted?
> 
> Yes we need to delete it in the destructor.

Done.

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.cc#newco...
runtime/vm/isolate.cc:800: lookup_mutex_(new Mutex()),
On 2016/07/01 17:16:18, Cutch wrote:
> where is this mutex deleted?

Done.

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.h
File runtime/vm/isolate.h (right):

https://codereview.chromium.org/2118813003/diff/1/runtime/vm/isolate.h#newcod...
runtime/vm/isolate.h:721: Mutex* lookup_mutex_;  // Protects megamorphic table
lookup.
On 2016/07/01 17:39:29, siva wrote:
> can we call it megamorphic_lookup_mutex_;
> so that it is more clear and people don't use it for other lookups.

Done.

[Florian Schneider, 2016-07-01 19:43:25]

Description was changed from

==========
Separate mutex for megamorphic cache tables lookup in the background compiler.

Lookup and updates to the megamorphic cache tables should be protected by a
separate mutex - using isolate->mutex() can cause a dead lock if the background
compiler holds this lock while it's being stopped by the mutator thread.

BUG=#26808
==========

to

==========
Separate mutex for megamorphic cache tables lookup in the background compiler.

Lookup and updates to the megamorphic cache tables should be protected by a
separate mutex - using isolate->mutex() can cause a dead lock if the background
compiler holds this lock while it's being stopped by the mutator thread.

BUG=#26808
R=asiva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/858ee49cea3e3cc30f1b444aa49a163de7eb1bf9
==========

[Florian Schneider, 2016-07-01 19:43:27]

Committed patchset #2 (id:20001) manually as
858ee49cea3e3cc30f1b444aa49a163de7eb1bf9 (presubmit successful).