application coredump behavior differences between FreeBSD 7.0 and FreeBSD 10.1

[Gavin Mu]

Hi,

We have an application running on old FreeBSD 7.0, and we are upgrading the base system to FreeBSD 10.1. The application uses sysv_shm, and will allocate a lot of share memory, though most of time only a part of the allocated memory is used. aka. large SIZE and small RES from /usr/bin/top view.

When the application core dump, the core dump file will be large, and in FreeBSD 7.0, it uses only a little more memory to do core dump, but in FreeBSD 10.1, it seems all share memory are touched and uses a lot of physical memory (RES in /usr/bin/top output will increase very much) and cause memory drain.

I have been debugging but can not find any clue yet. Could someone provide some points where the issue happen? Thanks.

Regards,
Gavin Mu