topic Re: What does "Memory class setup" mean? in Operating System - HP-UX

What does "Memory class setup" mean?

newa — Sun, 17 Jan 2010 20:46:41 GMT

Hi,

During the booting process of rp3440/hp-ux11i v2. The following was displayed on the console

Memory Class Setup
------------------------------------
Class Physmem Lockmem Swapmem
-------------------------------------
System : 12286 MB 12286 MB 12286 MB
Kernel : 12286 MB 12286 MB 12286 MB
User : 11499 MB 10020 MB 10059 MB
-------------------------------------

What does that mean? Can somebody please give me some explaination by line and columne? What's the total physical memory installed? (I think it's 12G. Is that right?)

Thanks a lot in advance.

Re: What does "Memory class setup" mean?

Johnson Punniyalingam — Mon, 18 Jan 2010 02:19:45 GMT

HP-UX will call firmware in physical-addresing mode.

Please check below thread for step by step explanation of HPUX booting process.

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1244789

>>(I think it's 12G. Is that right?)<<<

Yes its 12GB

Re: What does "Memory class setup" mean?

Kapil Jha — Mon, 18 Jan 2010 02:39:55 GMT

Well that is smthing i never gave any attention.

Well System line shows the memory installed on the server
so 12286 MB is the physical memory installed
12286 MB is the lockable memory for server.
12286 MB can be used as swap [not very sure on this anyone please explain].

for second line is for the kernel.
Kernel can use 12286 MB and lockable 12286 MB of memory

LAst is the memory available for user.

Hope this would help.

BR,
Kapil+

Re: What does "Memory class setup" mean?

Don Morris_1 — Mon, 18 Jan 2010 02:56:48 GMT

Memory Classes are the fundamental basis of memory reservation accounting in HP-UX 11i v1 and higher.

The reservation works by having a User Class (user memory comes from here) and a Kernel Class (kernel memory) -- both of which then reserve from the System Class (which represents the available resources on the box as a whole).

Physmem is physical memory. The amount put in the Class is the available memory to the system minus early boot kernel consumption [and any other memory the system does not consider reservable].

Lockmem is Lockable memory - memory resources that are not going to be eligible for paging out (kernel memory is locked, user memory can be locked via interfaces like mlock and plock).

Swapmem is Memory Swap -- memory resources that are allowed to be reserved in lieu of actual physical (disk or filesystem) swap. These are not particular pages, it is simply a matter of extending virtual address swap resources by knowing that the system will have physical swap resources for paging -- and then memory can stay resident and still back virtual objects. Memory swap appears as the "memory" line in swapinfo output.

Total physical memory at boot is likely close to 12Gb, yes -- but the memory _installed_ could be different as things like bad pages or disabled memory ranges could make the kernel view different from the machine view.

Re: What does "Memory class setup" mean?

newa — Mon, 18 Jan 2010 03:17:55 GMT

Thanks a lot Kapil and Don. You both answered my questions