Ok. The changes look fine to me then.
thanks,
Chris
On 2/20/19 6:02 PM, Yasumasa Suenaga wrote:
Hi Chris,
I grep'ed with "MAP_SHARED" on jdk/src.
Shared memory is used in ZGC (ZBackingFile and ZPhysicalMemoryBacking)
and in FileChannel::map at least.
I think we have memory footprint concern about them, but shared memory
should be dumped.
If we did not get them, we cannot analyze ZGC related behavior and
other code which uses shared memory.
(We can pass FD to os::reserve_memory - it will use shared memory if
FD is passed.)
Thus I want to introduce `DumpSharedMappingsInCore` for dumping shared
memory and set it to true by default.
Thanks,
Yasumasa
2019年2月21日(木) 3:10 Chris Plummer <chris.plum...@oracle.com>:
[adding runtime]
Hi Yasumasa,
Overall looks good. Just a couple of questions.
Do we have the same footprint concerns with the shared mappings as we
did with the private mappings? If not, possibly it doesn't need an
option and should always be enabled.
thanks,
Chris
On 2/20/19 12:03 AM, Yasumasa Suenaga wrote:
Hi all,
Please review this webrev:
JBS: https://bugs.openjdk.java.net/browse/JDK-8219414
webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8219414/webrev.00/
I tried to get PerfCounter values via `jhsdb jsnap` from core image
which is generated by `gcore` (provided by GDB), but I encountered
UnmappedAddressException.
It is caused by `generate-core-file` on GDB regards `coredump_filter` on procfs.
https://sourceware.org/gdb/onlinedocs/gdb/Core-File-Generation.html
JDK-8200613 introduced `DumpPrivateMappingsInCore` for CDS. I want to
introduce `DumpSharedMappingsInCore` for shared memory mapping.
Currently `DumpPrivateMappingsInCore` affects when `UseSharedSpaces` is enabled.
I want `DumpPrivateMappingsInCore` to affect independently in this
change because file-backed private memory which is not CDS might be
useful in the future.
Thanks,
Yasumasa
