History log of /art/runtime/lock_word-inl.h
Revision Date Author Comments
ef7d42fca18c16fbaf103822ad16f23246e2905d 06-Jan-2014 Ian Rogers <irogers@google.com> Object model changes to support 64bit.

Modify mirror objects so that references between them use an ObjectReference
value type rather than an Object* so that functionality to compress larger
references can be captured in the ObjectRefererence implementation.
ObjectReferences are 32bit and all other aspects of object layout remain as
they are currently.

Expand fields in objects holding pointers so they can hold 64bit pointers. Its
expected the size of these will come down by improving where we hold compiler
meta-data.
Stub out x86_64 architecture specific runtime implementation.
Modify OutputStream so that reads and writes are of unsigned quantities.
Make the use of portable or quick code more explicit.
Templatize AtomicInteger to support more than just int32_t as a type.
Add missing, and fix issues relating to, missing annotalysis information on the
mutator lock.
Refactor and share implementations for array copy between System and uses
elsewhere in the runtime.
Fix numerous 64bit build issues.

Change-Id: I1a5694c251a42c9eff71084dfdd4b51fff716822
c666ee8c75118d072bfd2a2b81b80915f6040593 24-Jan-2014 Ian Rogers <irogers@google.com> 64bit monitors are forced to 32bit in lock words.

I expect this to change in the future but this at least unblocks building.

Change-Id: I0baf3eb0e93f1e83d8f07947c1f24ba24249733c
590fee9e8972f872301c2d16a575d579ee564bee 13-Sep-2013 Mathieu Chartier <mathieuc@google.com> Compacting collector.

The compacting collector is currently similar to semispace. It works by
copying objects back and forth between two bump pointer spaces. There
are types of objects which are "non-movable" due to current runtime
limitations. These are Classes, Methods, and Fields.

Bump pointer spaces are a new type of continuous alloc space which have
no lock in the allocation code path. When you allocate from these it uses
atomic operations to increase an index. Traversing the objects in the bump
pointer space relies on Object::SizeOf matching the allocated size exactly.

Runtime changes:
JNI::GetArrayElements returns copies objects if you attempt to get the
backing data of a movable array. For GetArrayElementsCritical, we return
direct backing storage for any types of arrays, but temporarily disable
the GC until the critical region is completed.

Added a new runtime call called VisitObjects, this is used in place of
the old pattern which was flushing the allocation stack and walking
the bitmaps.

Changed image writer to be compaction safe and use object monitor word
for forwarding addresses.

Added a bunch of added SIRTs to ClassLinker, MethodLinker, etc..

TODO: Enable switching allocators, compacting on background, etc..

Bug: 8981901

Change-Id: I3c886fd322a6eef2b99388d19a765042ec26ab99
4e6a31eb97f22f4480827474b30b9e64f396eace 31-Oct-2013 Mathieu Chartier <mathieuc@google.com> Lazily compute object identity hash codes.

Before, we computed identity hashcodes whenever we inflated a monitor.
This caused issues since it meant that we would have all of these
hash codes in the image, causing locks to excessively inflate during
application run time.

This change makes it so that we lazily compute hash codes. When a
thin lock gets inflated, we assign a hash code of 0 assigned to it.
This value signifies no hash code. When we try to get the identity
hash code of an object with an inflated monitor, it gets computed if
it is 0.

Change-Id: Iae6acd1960515a36e74644e5b1323ff336731806
ad2541a59c00c2c69e8973088891a2b5257c9780 25-Oct-2013 Mathieu Chartier <mathieuc@google.com> Fix object identity hash.

The object identity hash is now stored in the monitor word after
being computed. Hashes are computed by a pseudo random number
generator.

When we write the image, we eagerly compute object hashes to
prevent pages getting dirtied.

Bug: 8981901

Change-Id: Ic8edacbacb0afc7055fd740a52444929f88ed564
d9c4fc94fa618617f94e1de9af5f034549100753 02-Oct-2013 Ian Rogers <irogers@google.com> Inflate contended lock word by suspending owner.

Bug 6961405.
Don't inflate monitors for Notify and NotifyAll.
Tidy lock word, handle recursive lock case alongside unlocked case and move
assembly out of line (except for ARM quick). Also handle null in out-of-line
assembly as the test is quick and the enter/exit code is already a safepoint.
To gain ownership of a monitor on behalf of another thread, monitor contenders
must not hold the monitor_lock_, so they wait on a condition variable.
Reduce size of per mutex contention log.
Be consistent in calling thin lock thread ids just thread ids.
Fix potential thread death races caused by the use of FindThreadByThreadId,
make it invariant that returned threads are either self or suspended now.

Code size reduction on ARM boot.oat 0.2%.
Old nexus 7 speedup 0.25%, new nexus 7 speedup 1.4%, nexus 10 speedup 2.24%,
nexus 4 speedup 2.09% on DeltaBlue.

Change-Id: Id52558b914f160d9c8578fdd7fc8199a9598576a