Re: [PATCH 5/5] [hugetlb] Try to grow pool for MAP_SHARED mappings

["Nish Aravamudan" <nish.aravamudan@gmail.com>]

On 7/20/07, Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:
> On Fri, 2007-07-20 at 13:35 -0700, Nish Aravamudan wrote:
> > On 7/18/07, Paul Mundt <lethal@linux-sh.org> wrote:
> <snip>
> > > It would be quite nice to have some way to have nodes opt-in to the sort
> > > of behaviour they're willing to tolerate. Some nodes are never going to
> > > tolerate spreading of any sort, hugepages, and so forth. Perhaps it makes
> > > more sense to have some flags in the pgdat where we can more strongly
> > > type the sort of behaviour the node is willing to put up with (or capable
> > > of supporting), at least in this case the nodes that explicitly can't
> > > cope are factored out before we even get to cpuset constraints (plus this
> > > gives us a hook for setting up the interleave nodes in both the system
> > > init and default policies). Thoughts?
> >
> > I guess I don't understand which nodes you're talking about now? How
> > do you spread across any particular single node (how I read "Some
> > nodes are never going to tolerate spreading of any sort")? Or do you
> > mean that some cpusets aren't going to want to spread (interleave?).
> >
> > Oh, are you trying to say that some nodes should be dropped from
> > interleave masks (explicitly excluded from all possible interleave
> > masks)? What kind of nodes would these be? We're doing something
> > similar to deal with memoryless nodes, perhaps it could be
> > generalized?
>
> If that's what Paul means [and I think it is, based on a converstation
> at OLS], I have a similar requirement.  I'd like to be able to specify,
> on the command line, at least [run time reconfig not a hard requirement]
> nodes to be excluded from interleave masks, including the hugetlb
> allocation mask [if this is different from the regular interleaving
> nodemask].

Right this would avoid using that DMA node for your systems.

> And, I agree, I think we can add another node_states[] entry or two to
> hold these nodes.  I'll try to work up a patch next week if noone beats
> me to it.

Sounds good. I think the commandline interface might be a bit hairy --
but I'll leave that to you :)

So then, I'd say, by default the interleave masks should be and'd with
this node_states(N_INTERLEAVE), where if not otherwise specified,
node_states(N_INTERLEAVE) == node_states[N_MEMORY]?

Thanks,
Nish

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