From: David Gibson <david@gibson.dropbear.id.au>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org, Mel Gorman <MELGOR@ie.ibm.com>,
Anton Blanchard <anton@samba.org>
Subject: Re: powerpc: Move 64bit heap above 1TB on machines with 1TB segments
Date: Wed, 23 Sep 2009 10:03:14 +1000 [thread overview]
Message-ID: <20090923000314.GB26739@yookeroo.seuss> (raw)
In-Reply-To: <1253653702.7103.244.camel@pasglop>
On Wed, Sep 23, 2009 at 07:08:22AM +1000, Benjamin Herrenschmidt wrote:
>
> > Unfortunately, I am not sensitive to issues surrounding 1TB segments or how
> > they are currently being used. However, as this clearly helps performance
> > for large amounts of memory, is it worth providing an option to
> > libhugetlbfs to locate 16MB pages above 1TB when they are otherwise being
> > unused?
>
> AFAIK, that is already the case, at least the kernel will hand out pages
> above 1T preferentially iirc.
>
> There were talks about making huge pages below 1T not even come up
> untily you ask for them with MAP_FIXED, dunno where that went.
That was already the case as far as I remember. But it's just
possible that changed when the general slice handling code came in,
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
next prev parent reply other threads:[~2009-09-23 0:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-22 2:52 powerpc: Move 64bit heap above 1TB on machines with 1TB segments Anton Blanchard
2009-09-22 14:47 ` Mel Gorman
2009-09-22 21:08 ` Benjamin Herrenschmidt
2009-09-23 0:03 ` David Gibson [this message]
2009-09-23 12:50 ` Mel Gorman
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