On Monday 05 January 2009 22:00:33 Dave Hansen wrote:
> OK, I had to think about this for a good, long time. That's bad. :)
>
> There are two things that we're dealing with here: "active regions" and
> the NODE_DATA's. The if() you've pasted above resizes the reservation
> so that it fits into the current active region. However, as you noted,
> we haven't resized it so that it fits into the NODE_DATA() that we're
> looking at. We call into the bootmem code, and BUG_ON().
>
> The thing I don't like about this is that it might hide bugs in other
> callers. This really is a ppc-specific thing and, although what you
> wrote will fix the bug on ppc, it will probably cause someone in the
> future to call reserve_bootmem_node() with too large a reservation and
> get a silent failure (not reserving the requested size) back.
>
> We really do need to go take a hard look at the whole interaction
> between lmb's, node active regions, and the NUMA code some day. It has
> kinda grown to be a bit ungainly.
>
> How about we just consult the NODE_DATA() in
> mark_reserved_regions_for_nid() instead of reserve_bootmem_node()?
I don't know how you wanted NODE_DATA() to be consulted here. i.e before
calling reserve_bootmem_node() should we have a condition
if (PFN_UP(physbase+reserve_size) > node_end_pfn)
then
resize reserve_size again so that PFN_UP() will equate to
node_end_pfn ??
end
Also I was wondering if in reserve_bootmem_node()
end = PFN_DOWN() ; will do..
With the recent changes from you that went into 2.6.28 stable
(commit:a4c74ddd5ea3db53fc73d29c222b22656a7d05be), it worked on the system
with PFN_DOWN().
Thanks,
Chandru
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