What does the U-Area & K-Stack mean in HP UX?

[Du, Guang (Wolfee)]

I'm trying to use the pstat APIs to get some system information and process information.
The __pst_status struct contains one element:
_T_LONG_T pst_usize; /* # real pages used for U-Area & K-Stack */

What does this mean in HP UX? I've ever tried to look up in Internet and also this forum, and also related books but got no information.

Thank you for anyone that could give me some information.

[Don Morris_1 · Accepted solution]

It means the physical space set aside for kernel thread operations (the kernel thread stack, some register caching, Whatever Else the Kernel Decides It Wants To Put There ).

Usually, UAREA is used to describe this virtual/physical object. The kernel stack for a kernel thread is a sub-set of the UAREA.

For more information (as with most VM concepts -- well, this one's almost a Process Management issue more than VM, we just have to give them memory), the Memory Management Whitepaper is always a good read:
http://docs.hp.com/en/1218/mem_mgt.html

[Du, Guang (Wolfee)]

Thank you Don for your information :-)

I'm closing this thread now.

[Du, Guang (Wolfee)]

Thank you Don for your information about the U-Area and also the link.