[dpdk-dev] memory allocation requirements

[Thomas Monjalon <thomas.monjalon@6wind.com>]

After looking at the patches for container support, it appears that
some changes are needed in the memory management:
http://thread.gmane.org/gmane.comp.networking.dpdk.devel/32786/focus=32788

I think it is time to collect what are the needs and expectations of
the DPDK memory allocator. The goal is to satisfy every needs while
cleaning the API.
Here is a first try to start the discussion.

The memory allocator has 2 classes of API in DPDK.
First the user/application allows or requires DPDK to take over some
memory resources of the system. The characteristics can be:
	- numa node
	- page size
	- swappable or not
	- contiguous (cannot be guaranteed) or not
	- physical address (as root only)
Then the drivers or other libraries use the memory through
	- rte_malloc
	- rte_memzone
	- rte_mempool
I think we can integrate the characteristics of the requested memory
in rte_malloc. Then rte_memzone would be only a named rte_malloc.
The rte_mempool still focus on collection of objects with cache.

If a rework happens, maybe that the build options CONFIG_RTE_LIBRTE_IVSHMEM
and CONFIG_RTE_EAL_SINGLE_FILE_SEGMENTS can be removed.
The Xen support should also be better integrated.

Currently, the first class of API is directly implemented as command line
parameters. Please let's think of C functions first.
The EAL parameters should simply wrap some API functions and let the
applications tune the memory initialization with a well documented API.

Probably that I forget some needs, e.g. for the secondary processes.
Please comment.