On 4/16/20 11:55 AM, Calvin Cheung wrote:
On 4/16/20 11:12 AM, Ioi Lam wrote:
On 4/16/20 10:08 AM, Calvin Cheung wrote:
Hi Ioi,
Regarding the changes in javaClasses.cpp, I saw that in your new
code in systemDictionaryShared.cpp, the
java_lang_Class::update_archived_mirror_native_pointers(m) won't be
called if MetaspaceShared::relocation_delta() is 0. But I noticed
there's another code path to
java_lang_Class::update_archived_mirror_native_pointers() after
HeapShared::fixup_mapped_heap_regions() is called in
SystemDictionary::resolve_well_known_classes():
java_lang_Class::update_archived_mirror_native_pointers(oop) : void
java_lang_Class::restore_archived_mirror(Klass *, Handle,
Handle, Handle, Thread *) : bool
java_lang_Class::fixup_mirror(Klass *, Thread *) : void
Universe::fixup_mirrors(Thread *) : void
SystemDictionary::resolve_well_known_classes(Thread *) : void
SystemDictionary::initialize(Thread *) : void
Universe::genesis(Thread *) : void
universe2_init() : void
init_globals() : ?
Will MetaspaceShared::relocation_delta() always be non-zero in the
above case?
Hi Calvin,
Thanks for taking a look at this.
As part of this patch, the call path that you mentioned above has
been removed. Now we always call
update_archived_mirror_native_pointers on all archived classes at VM
start-up, so there's no need to patch individual mirrors during class
loading.
See the change on line 1294.
http://cr.openjdk.java.net/~iklam/jdk15/8241158-sa-heap-dump-fails.v01/src/hotspot/share/classfile/javaClasses.cpp.cdiff.html
I see. The proposed change looks good.
Thanks Calvin!
- Ioi
thanks,
Calvin
Thanks
- Ioi
thanks,
Calvin
On 4/14/20 10:07 PM, Ioi Lam wrote:
Hi Chris,
Thanks for the info. I've synced with the latest repo and updated
the webrev in-place:
http://cr.openjdk.java.net/~iklam/jdk15/8241158-sa-heap-dump-fails.v01/
I'll rerun tiers 1-4 as two of the affected tests
(ClhsdbDumpheap.java, TestHeapDumpForInvokeDynamic.java) will now
be executed on macos by mach5.
Thanks
- Ioi
On 4/14/20 3:34 PM, Chris Plummer wrote:
[Not a review]
Hi Ioi,
Your ProblemList.txt is out of date. All those Solaris entries for
8193639 are now gone.
thanks,
Chris
On 4/14/20 3:01 PM, Ioi Lam wrote:
https://bugs.openjdk.java.net/browse/JDK-8241158
http://cr.openjdk.java.net/~iklam/jdk15/8241158-sa-heap-dump-fails.v01/
This is a bug in the CDS relocation code. When
-XX:ArchiveRelocationMode=1 is
specified, the CDS archive is mapped to an address picked by the OS
(instead of the default address 0x800000000). As a result, we
need to patch
the native Klass* pointers inside java.lang.Class instances that are
stored in the CDS archived heap region.
Before this fix, the patching is done incrementally, when a class
is resolved.
However, when SA tries to do a heap dump, it may see a
java.lang.Class instance
that is not yet resolved, whose Klass* pointer has not been patched.
Dereferencing the unpatched pointer causes SA to fail.
(The failure happens on macos only, probably because the invalid
dereference
causes different exceptions on other platforms due to specific
memory layout,
and SA is able to handle such exceptions and limp on).
The fix is to unconditionally patch all the Klass* pointers
during VM
initialization.
We already patch a lot of stuff at start-up when the CDS archive
is relocated,
so doing a little patching more doesn't hurt.
----
Passed mach5 tiers 1-4. Ran the failed test manually on macos and
it passed.
Thanks
- Ioi
