Re: Auto-tune shared_buffers to use available huge pages

Anthonin Bonnefoy <anthonin(dot)bonnefoy(at)datadoghq(dot)com> writes:
> To help with that, the attached patch provides a new option,
> huge_pages_autotune_buffers, to automatically use leftover huge pages
> as shared_buffers. This requires some changes in the auto-tune logic:

Not expressing an opinion on whether we should do this, but
there is a comment on GetHugePageSize() that you seem to have
falsified without bothering to correct:

* Doing the round-up ourselves also lets us make use of the extra memory,
* rather than just wasting it. Currently, we just increase the available
* space recorded in the shmem header, which will make the extra usable for
* purposes such as additional locktable entries. Someday, for very large
* hugepage sizes, we might want to think about more invasive strategies,
* such as increasing shared_buffers to absorb the extra space.

regards, tom lane