Thanks, Erik.
StefanK
On 2019-02-18 10:35, Erik Österlund wrote:
Hi Stefan,
Looks good!
Thanks,
/Erik
On 2019-02-15 20:25, Stefan Karlsson wrote:
Testing showed that the re-enabling of the retiring of TLABs was
broken. This has been fixed with this patch:
http://cr.openjdk.java.net/~stefank/8218922/webrev.03.delta
http://cr.openjdk.java.net/~stefank/8218922/webrev.03
During mark start we change what's considered the "good" view of the
heap, and if -XX:+ZUnmapBadViews is turned on we actually unmap the
previous good view. This happens before TLABs are retired and filler
objects get written. This used to work when we didn't create filler
objects for TLABs, but know that we do, we need to ensure that the
TLAB pointers have the correct colors, otherwise we'll end up crashing
when -XX:+ZUnmapBadViews are used.
With this fix, the patches passes tier1,tier2, and tier3 testing.
Thanks,
StefanK
On 2019-02-13 15:52, Stefan Karlsson wrote:
Hi all,
Please review / comment on this patch to enable a best-effort live
heap region iteration implementation in ZGC.
http://cr.openjdk.java.net/~stefank/8218922/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8218922
The SA has functionally that relies on live heap region information
from the GCs. This is problematic when dead objects are left in the
heap, and their classes have been unloaded.
Because of this ZGC has so far not implemented this feature. However,
we could provide a best-effort implementation that most likely will
work if classes are not unloaded (or class unloading is turned off),
and otherwise might fail to fully parse and report all live heap
regions.
For active, non-relocating pages the patch simply returns [start,
top) and for pages being actively relocated, it reports regions
containing the non-forwarded objects, the other objects are either
dead or could be found in one of the to-regions.
With this patch I'm able to get heap histograms with ZGC.
Maybe this is enough to enable a bit more SA debugging capabilities
when running with ZGC? What do you think, should we bring in this
change?
To be able to implement this more cleanly I've restructured the live
region collection, and pushed GC specific code into the specific GCs.
There are some extra usage of generics to make the code a bit easier
to read and develop.
Thanks,
StefanK
