On 7/12/2020 5:44 pm, Chris Plummer wrote:
On Mon, 7 Dec 2020 06:27:20 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c line 1560:
1558: * garbage collected while the VM is suspended.
1559: */
1560: commonRef_pinAll();
Can we have multiple VM.suspend calls? The suspendAllCount seems to suggest that. In
which case shouldn't we only pin on the 0->1 transition, and only unpin on the
1->0 transition?
That was something I pointed out in the pre-review, and it has been addressed
in `commonRef_pinAll/unpinAll`:
`568 if (gdata->pinAllCount == 1) {`
`618 if (gdata->pinAllCount == 0) {`
Okay. I would not have handled it at that level, but would have had
pinAll/unpinAll operate unconditionally, but the calls to those methods
being conditional based on the suspendAllCount.
David
Well, that's assuming `pinAll()` will only ever be used by by `suspendAll()`.
One could imaging a future use, such as if `VirtualMachine.disableCollection()`
were ever to be added.
Not really. I consider pinAll should pin-all as the name implies. The
question of when to pin should be handled by the caller of pinAll. If
there were ever to be a second reason to pinAll then you would have to
decide what semantics that has: does it maintain a count, or is it like
thread suspension.
David
-------------
PR: https://git.openjdk.java.net/jdk/pull/1595
