Re: [PATCH] Use MAP_HUGETLB where supported (v3)

From: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
To: Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>
Cc: Christian Kruse <christian(at)2ndQuadrant(dot)com>, Andres Freund <andres(at)2ndQuadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Bruce Momjian <bruce(at)momjian(dot)us>, Peter Eisentraut <peter_e(at)gmx(dot)net>, Abhijit Menon-Sen <ams(at)2ndQuadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] Use MAP_HUGETLB where supported (v3)
Date: 2014-02-26 16:13:02
Message-ID: 20140226161302.GD4759@eldon.alvh.no-ip.org
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There's one thing that rubs me the wrong way about all this
functionality, which is that we've named it "huge TLB pages". That is
wrong -- the TLB pages are not huge. In fact, as far as I understand,
the TLB doesn't have pages at all. It's the pages that are huge, but
those pages are not TLB pages, they are just memory pages.

I think we have named it this way only because Linux for some reason
named the mmap() flag MAP_HUGETLB for some reason. The TLB is not huge
either (in fact you can't alter the size of the TLB at all; it's a
hardware thing.) I think this flag means "use the TLB entries reserved
for huge pages for the memory I'm requesting".

Since we haven't released any of this, should we discuss renaming it to
just "huge pages"?

--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

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