On Tuesday, 23 September 2014 at 18:53:04 UTC, Oscar Martin wrote:
On Tuesday, 23 September 2014 at 15:28:30 UTC, Marc Schütz
wrote:
On Tuesday, 23 September 2014 at 15:23:16 UTC, Kagamin wrote:
And what GC does? Pins the allocated blocks for another
thread?
Assuming there is one thread-local GC per thread, it transfers
responsibility of the allocated data from the sender to the
receiver. This means, the old GC doesn't need to scan it any
more, but the new one does.
Yes. A mechanism for transfer of responsibility and pins would
be needed.
Basically we have to think that a thread GC just look for roots
on his stack/registers and managed memory, and may move the
managed objects in a collection, so a reference used in another
thread may become invalid for that other thread anytime
Physically moving the objects is not necessary, it only needs to
"move" the responsibility. With some work, it might even be
possible to move the objects' metadata from the old to the new
heap, so that each GC would only need to access its own heap
during a scan, which avoids synchronization with the other
threads.
