Hi Roman,
A few things:
1) The code uses the "mgr" short name for "manager" in a bunch of names.
I would be happy if we could write out the whole thing instead of the
abbreviation.
2) It would be great if a generation would have a pointer to its
manager, so we do not have to pass around the manager where we already
pass around the generation (such as GenCollectedHeap::collect_generation).
The generation could be created first, then the pools, then the
managers, then do something like generation->set_memory_manager(x).
3) In cmsHeap.cpp:54: maxSize should preferably not use camel case.
Otherwise I think it looks good.
Thanks,
/Erik
On 2017-11-27 10:30, Roman Kennke wrote:
Erik implemented a few more refactorings and touch-ups, and here is
our final (pending reviews) webrev:
http://cr.openjdk.java.net/~rkennke/8191564/webrev.04/
Compared to webrev.02, it improves the handling of gc-end-message,
avoids dragging the GCMemoryManager through Generation and a few
little related refactorings.
Ok to push now?
Roman
After a few more discussions with Erik I made some more changes.
MemoryService is now unaware of the number and meaning of GC memory
managers (minor vs major). This should be better for GCs that don't
make that distinction and/or use more different GCs (e.g. minor,
intermediate, full).
This means that I needed to add some abstractions:
- GCMemoryManager now has gc_end_message() which is used by
GCNotifier::pushNotification().
- gc_begin() and gc_end() methods in MemoryService now accept a
GCMemoryManager* instead of bull full_gc
- Same for TraceMemoryManagerStats
- Generation now knows about the corresponding GCMemoryManager
Please review the full change:
http://cr.openjdk.java.net/~rkennke/8191564/webrev.02/
Thanks, Roman
I had some off-band discussions with Erik Helin and re-did most of
the changeset:
- The GC interface now resides in CollectedHeap, specifically the
two methods memory_managers() and memory_pools(), and is implemented
in the various concrete subclasses.
- Both methods return (by value) a GrowableArray<GCMemoryManager*>
and GrowableArray<MemoryPool> respectively. Returning a
stack-allocated GrowableArray seemed least complicated (avoid
explicit cleanup of short-lived array object), and most
future-proof, e.g. currently there is an implicit expectation to get
2 GCMemoryManagers, even though some GCs don't necessarily have two.
The API allows for easy extension of the situation.
http://cr.openjdk.java.net/~rkennke/8191564/webrev.01/
I think this requires reviews from both the GC and Serviceability team.
Roman
Currently, there's lots of GC specific code sprinkled over
src/hotspot/share/services. This change introduces a GC interface
for that, and moves all GC specific code to their respective
src/hotspot/share/gc directory.
http://cr.openjdk.java.net/~rkennke/8191564/webrev.00/
<http://cr.openjdk.java.net/%7Erkennke/8191564/webrev.00/>
Testing: hotspot_gc and hotspot_serviceability, none showed
regressions
Built minimal and server without regressions
What do you think?
Roman
