Re: [PATCH 0/6] Sizing zones and holes in an architecture independentmanner V9

From: Mel Gorman
Date: Tue Aug 22 2006 - 04:36:34 EST

On Mon, 21 Aug 2006, Keith Mannthey wrote:

On 8/21/06, Mel Gorman <mel@xxxxxxxxx> wrote:
This is V9 of the patchset to size zones and memory holes in an
architecture-independent manner. It booted successfully on 5 different
machines (arches were x86, x86_64, ppc64 and ia64) in a number of different
configurations and successfully built a kernel. If it fails on any machine,
booting with loglevel=8 and the console log should tell me what went wrong.

I am wondering why this new api didn't cleanup the pfn_to_nid code
path as well. Arches are left to still keep another set of
nid-start-end info around. We are sending info like

pfn_to_nid() is used at runtime and the early_node_map[] is deleted by then. As this step, I only want to get the initialisation correct. What can be replaced is the architecture-specific early_pfn_to_nid() function which I did for power and x86.

add_active_range(unsigned int nid, unsigned long start_pfn, unsigned
long end_pfn)

With this info making a common pnf_to_nid seems to be of intrest so we
don't have to keep redundant information in both generic and arch
specific data structures.

To implement a common one of interest, the array would have to be converted to a linked list at the end of boot so it could be modified by memory hot-add, then pfn_to_nid() would walk the linked list rather than the existing array. pfn_valid() would probably be replaced as well. However, this is going to be slower (if more accurate in some cases) than the existing pfn_valid() and so I would treat it as a separate issue.

Are you intending the hot-add memory code path to call add_active_range or ???

Not at this time. I want to make sure the memory initialisation is right before dealing with additional complications.


Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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