Messages in this thread | | | Subject | Re: [RFC] Hugetlb demotion for x86 | From | Adam Litke <> | Date | Thu, 11 May 2006 10:59:53 -0500 |
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On Thu, 2006-05-11 at 16:15 +0100, Hugh Dickins wrote: > 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.
I guess it's time for me to take a step back and explain why I am doing this. libhugetlbfs (announced here recently) has the ability to remap an executable's ELF segments into huge pages. So madvise(MADV_DONTFORK) would be pretty bad ;)
-- Adam Litke - (agl at us.ibm.com) IBM Linux Technology Center
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