Re: Huge pages not working on PG 9.4

Michael Heaney <mheaney(at)jcvi(dot)org> writes:
> On 1/16/2015 6:58 PM, Tom Lane wrote:
>> A quick look at the PG source code says that that message means that
>> MAP_HUGETLB isn't defined. Our code is expecting <sys/mman.h> to provide
>> that symbol, which it should do by default according to what I can see on
>> my RHEL 6.6 box. Perhaps you've defined some of the feature restriction
>> macros like _POSIX_SOURCE?

> Thanks for the helpful clue, Tom. I haven't knowingly defined
> _POSIX_SOURCE or any other macros. I go through the same configure/make
> process on the Centos 6.6 VM on my home PC, and huge pages works just
> fine. Maybe it's an issue with CentOS 6.4?

Dunno, hard to believe that hugetlb support wasn't there in 6.4. A quick
troll through the RHEL 6.5 and 6.6 release notes finds something about
better hugetlb support for System Z processors, but what we're discussing
here shouldn't be architecture-specific.

You might try comparing /usr/include/sys/mman.h, /usr/include/bits/mman.h,
and /usr/include/features.h between your 6.4 and 6.6 systems to see if
you can spot any relevant differences.

regards, tom lane