Re: [PATCH 4/4] hugetlb: add hugepages_node= command-line option

From: Luiz Capitulino
Date: Thu Feb 20 2014 - 11:08:43 EST


On Wed, 19 Feb 2014 20:51:55 -0800 (PST)
David Rientjes <rientjes@xxxxxxxxxx> wrote:

> On Wed, 19 Feb 2014, Luiz Capitulino wrote:
>
> > > Yes, my concrete objection is that the command line interface is
> > > unnecessary if you can dynamically allocate and free 1GB pages at runtime
> > > unless memory will be so fragmented that it cannot be done when userspace
> > > is brought up. That is not your use case, thus this support is not
> >
> > Yes it is. The early boot is the most reliable moment to allocate huge pages
> > and we want to take advantage from that.
> >
>
> Your use case is 8GB of hugepages on a 32GB machine. It shouldn't be
> necessary to do that at boot.

That's shortsighted because it's tied to a particular machine. The same
customer asked for more flexibility, too.

Look, we're also looking forward to allocating 1G huge pages from user-space.
We actually agree here. What we're suggesting is having _both_, the
command-line option (which offers higher reliability and is a low hanging
fruit right now) _and_ later we add support to allocate 1G huge pages from
user-space. No loss here, that's the maximum benefit for all users.
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