* Use real isolate in concurrent sweeper rather than shallow copy.
The only part of the isolate, other than the page being swept, used by the sweeper is the class table (via RawObject::Size), which is now safe to read concurrently (copy-on-write).
* Do not eagerly destroy a VM thread whenever it exits an isolate.
This extends the lifetime of a VM thread across entering/exiting multiple isolates. This is necessary in case an embedder callback executes during
compilation and switches/spawns isolates.
For embedder threads, since there is no API to signal "I'm done using the VM in this thread", this means we leak the (small) Thread structure.
For our own ThreadPool threads, we explicitly clean up.
BUG=23153
R=iposva@google.com
Review URL: https://codereview.chromium.org//1136143003
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@45810 260f80e4-7a28-3924-810f-c04153c831b5
Since the Thread structure is currently cleared on Enter/ExitIsolate,
there is a risk that CHA is cleared if an embedder callback executes during
compilation and switches/spawns isolates. This CL eliminates that risk.
However, Isolate is still not a good long-term place for CHA,
since it doesn't fit with a concurrent compilation model. Issue 23153 tracks
the work towards a permanent solution that couples its life cycle with
compilation.
R=fschneider@google.com, iposva@google.com
Review URL: https://codereview.chromium.org//1061243003
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@45121 260f80e4-7a28-3924-810f-c04153c831b5
The life cycle of Thread is still coupled with the life cycle of Isolate, but the added indirection allows the migration work to proceed, at negligible performance impact.
This is a small step towards making Thread different from Isolate and allow a many-to-one relationship. In particular, in prepares for being able to have the sweeper have some minimal separate state from the main thread (eliminating the current fake-isolate hack).
Concretely, it moves the thread-local storage key into the Thread class, but for now, keeps a "main_thread" in Isolate for quick access in native/runtime_entry.
Also moves cha_ field to Thread (the first of many fields that will move).
To summarize, this CL enables the next steps:
- moving other fields from Isolate to Thread without circular include-dependencies
- replacing sweeper's fake Isolate with a helper Thread (referencing the original Isolate)
Also add 'volatile' to local variables that clang thinks could be clobbered.
R=asiva@google.com
Review URL: https://codereview.chromium.org//1037453002
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@44703 260f80e4-7a28-3924-810f-c04153c831b5
koda@google.com