Update: [Automatic] NUMA replicated pagecache on 2.6.23-rc4-mm1

[Lee Schermerhorn <Lee.Schermerhorn@hp.com>]

[Balbir:  see notes re:  replication and memory controller below]

A quick update:  I have rebased the automatic/lazy page migration and
replication patches to 23-rc4-mm1.  If interested, you can find the
entire series that I push in the '070911' tarball at:

	http://free.linux.hp.com/~lts/Patches/Replication/

I haven't gotten around to some of the things you suggested to address
the soft lockups. etc.  I just wanted to keep the patches up to date.  

In the process of doing a quick sanity test, I encountered an issue with
replication and the new memory controller patches.  I had built the
kernel with the memory controller enabled.  I encountered a panic in
reclaim, while attempting to "drop caches", because replication was not
"charging" the replicated pages and reclaim tried to deref a null
"page_container" pointer.  [!!! new member in page struct !!!]

I added code to try_to_create_replica(), __remove_replicated_page() and
release_pcache_desc() to charge/uncharge where I thought appropriate
[replication patch # 02].  That seemed to solve the panic during drop
caches triggered reclaim.  However, when I tried a more stressful load,
I hit another panic ["NaT Consumption" == ia64-ese for invalid pointer
deref, I think] in shrink_active_list() called from direct reclaim.
Still to be investigated.  I wanted to give you and Balbir a heads up
about the interaction of memory controllers with page replication.

Later,
Lee

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