use of lockable memory in HP

[Dean Chan]

Is there anyone knows how oracle make use the lockable memory in HP. From HP's doc., this part of memory area is accessible by some privilege library call such as plock and mlock. Users who don't belongs to MLOCK privilege group cannot access this part of memory.

My case is that the oracle in my machine does not belongs to the mentioned privileged group but it is running. My concern is that the lockable memory in my machine allocate 75% of the physical memory and only 11% (~330M) of the physical memory is claimed to be unlockable. This means that the instances may use the physical memory inefficiently.

Does anyone know that Oracle can use the lockable in some way or it doesn't use it anyway?
How to query what are resident in lockable memory and what are resident in unlockable memory.

[Mahesh Kumar Malik]

Hi Dean

Please visit follwoing URL:

http://docs.hp.com/en/B8844-90006/apfs02.html

Regards
Mahesh

[Don Morris_1]

I think you're a little confused on the lockable/unlockable status of physical memory. With the default unlockable_mem setting (and swapmem_on set to 1), about 3/4 of the memory would be considered lockable... which just means that the kernel will *allow* that much to be locked... not that only allocations which intend to lock are granted that memory. Oracle presumably is smart enough to handle the failure of the mlock() call and keeps going. It may not get optimal performance if the system load increases to where vhand is active (since Oracle's pages are potentially swapped out as well and would have to be swapped back in on demand) -- but it certainly gets the physical memory if the kernel can provide it.

[Dean Chan]

Thanks folks for the clarification