postgresql/doc
Heikki Linnakangas 1a3458b6d8 Allow using huge TLB pages on Linux (MAP_HUGETLB)
This patch adds an option, huge_tlb_pages, which allows requesting the
shared memory segment to be allocated using huge pages, by using the
MAP_HUGETLB flag in mmap(). This can improve performance.

The default is 'try', which means that we will attempt using huge pages,
and fall back to non-huge pages if it doesn't work. Currently, only Linux
has MAP_HUGETLB. On other platforms, the default 'try' behaves the same as
'off'.

In the passing, don't try to round the mmap() size to a multiple of
pagesize. mmap() doesn't require that, and there's no particular reason for
PostgreSQL to do that either. When using MAP_HUGETLB, however, round the
request size up to nearest 2MB boundary. This is to work around a bug in
some Linux kernel versions, but also to avoid wasting memory, because the
kernel will round the size up anyway.

Many people were involved in writing this patch, including Christian Kruse,
Richard Poole, Abhijit Menon-Sen, reviewed by Peter Geoghegan, Andres Freund
and me.
2014-01-29 14:08:30 +02:00
..
src Allow using huge TLB pages on Linux (MAP_HUGETLB) 2014-01-29 14:08:30 +02:00
bug.template Stamp HEAD as 9.4devel. 2013-06-14 14:41:28 -04:00
KNOWN_BUGS
Makefile Remove maintainer-check target, fold into normal build 2013-10-10 20:11:56 -04:00
MISSING_FEATURES
TODO