Questions about the numa support implementation of Linux

[Christos Margiolas <chrmargiolas@googlemail.com>]

Hello,
Few weeks now, I'm working on a map reduce implementation for numa
systems(cell be and amd64 arch) and I have searched the web and irc
channels for information about numa support on Linux. I study about
the libnuma v2.1 library and I wrote some test programs and I
understood enough good the library api. But I still have enough
questions and I think they're kernel support relative. I will try
indite my questions as simple as possible in order to save your time.

I know that the operating system(Linux) is  running on a single node
and it's not distributed over the nodes.

a)When a process or a process's thread is executing on a node(not the
same with the kernel), the local memory(execution node of process or
thread) has a copy of the text and data segments or there are always
references to the memory of the node with the os where the data and
text segments would legacy be? If the final is true, this is a big
bottleneck.

b)Memory allocation system calls which is used by standard c library
api (malloc, calloc, realloc) are aware about numa policy on memory
systems? Or only with the libnuma calls is possible to allocate memory
effectively with respect on numa bind restrictions?

c)If a strict memory  policy was specified, which designates specific
nodes, and the nodes  are out of memory resources, the system will
kill the process or it will will use the swap as it does for a normal
uniform memory system?

Now a question relative with scheduler conduct:

d)When a processor binding function(scheduler or numa api call)
returns the schedulers has applied the requested policy or the changes
will take effect after the context switch? I have the same question
about memory policy appliance.

e)Also the shared libs running only on the kernel's node, right?

I will appreciate also any link or study material about numa on Linux.

Chris Margiolas
Undergraduate Student
Computer Science Department
University of Crete
Ics Forth Computer Architecture
and VLSI Systems Lab