Re: [RFC][PATCH 2/3] hugetlb: numafy several functions

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

On Wed, 2007-05-23 at 10:51 -0700, Nishanth Aravamudan wrote:
> On 16.05.2007 [16:31:55 -0700], Nishanth Aravamudan wrote:
> > Add node-parameterized helpers for dequeue_huge_page,
> > alloc_fresh_huge_page and try_to_free_low. Also have
> > update_and_free_page() take a nid parameter. This is necessary to add a
> > per-node sysfs attribute to specify the number of hugepages on that
> > node.
> 
> I saw that 1/3 was picked up by Andrew, but have not got any responses
> to the other two (I know Adam is out of town...).

Nish:  I haven't had a chance to test these patches.  Other alligators
in the swamp right now.

> 
> Thoughts, comments? Bad idea, good idea?
> 
> I found it pretty handy to specify the exact layout of hugepages on each
> node.

Could be useful for system with unequal memory per node, or where you
know you want more huge pages on a given node.  I recall that Tru64 Unix
used to support something similar:  most vm tunables that involved sizes
or percentages of memory, such as page cache limits, locked memory
limits, reserved huge pages, ..., could be specified as a single value
that was distributed across nodes [backwards compatibility] or as list
of per node values.  However, I don't recall if marketing/customers
asked for this or if it was a case of gratuitous design excess ;-).

I see that we'll need to reconcile the modified alloc_fresh_huge_page
with the patch to skip unpopulated nodes when/if they collide in -mm.

Lee


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