Re: [RFC] Hugetlb demotion for x86

[Hugh Dickins <hugh@veritas.com>]

On Wed, 10 May 2006, Adam Litke wrote:
> 
> Strict overcommit is there for shared mappings.  When private mapping

I presume that by "strict overcommit" you mean "strict no overcommit".

> support was added, people agreed that full overcommit should apply to
> private mappings for the same reasons normal page overcommit is desired.

I'm not sure how wide that agreement was.  But what I wanted to say is...

> For one: an application using lots of private huge pages should not be
> prohibited from forking if it's likely to just exec a small helper
> program.

This is an excellent use for madvise(start, length, MADV_DONTFORK).
Though it was added mainly for RDMA issues, it's a great way for a
program with a huge commitment to exclude areas of its address space
from the fork, so making that fork much more likely to succeed.

Hugh