linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Scott Wood <oss@buserror.net>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
	LinuxPPC-dev <linuxppc-dev@lists.ozlabs.org>,
	Becky Bruce <beckyb@kernel.crashing.org>,
	David Gibson <david@gibson.dropbear.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [RFC] Implementing HUGEPAGE on MPC 8xx
Date: Wed, 08 Jun 2016 19:15:08 -0500	[thread overview]
Message-ID: <1465431308.22191.101.camel@buserror.net> (raw)
In-Reply-To: <b2980a9d-4795-ae1b-16dd-ba244d559a31@c-s.fr>

On Wed, 2016-06-08 at 09:03 +0200, Christophe Leroy wrote:
> In see in the current ppc kernel that for PPC32, SYS_SUPPORTS_HUGETLBFS 
> is selected only if we have PHYS_64BIT.
> What is the reason for only implementing HUGETLBFS with 64 bits phys 
> addresses ?

That's not for PPC32 in general -- it's for 32-bit FSL Book E.  The reason for
the limitation is that there are separate TLB miss handlers depending on
whether PHYS_64BIT is enabled, and we didn't want to have to implement hugetlb
support in both of them unless there was actual demand for it.

>  From your point of view, what would be the best approach to extend 
> support of HUGE PAGES to PPC_8xx ?
> Would the good starting point be to implement a hugepagetlb-8xx.c from 
> hugepagetlb-book3e.c ?

Yes.

-Scott

      parent reply	other threads:[~2016-06-09  0:15 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-08  7:03 [RFC] Implementing HUGEPAGE on MPC 8xx Christophe Leroy
2016-06-08 22:46 ` Dan Malek
2016-06-09  0:15 ` Scott Wood [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1465431308.22191.101.camel@buserror.net \
    --to=oss@buserror.net \
    --cc=beckyb@kernel.crashing.org \
    --cc=benh@kernel.crashing.org \
    --cc=christophe.leroy@c-s.fr \
    --cc=david@gibson.dropbear.id.au \
    --cc=linuxppc-dev@lists.ozlabs.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).