All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dan Williams <dan.j.williams@intel.com>
To: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Linux NVDIMM <nvdimm@lists.linux.dev>,
	linux-s390 <linux-s390@vger.kernel.org>
Subject: Re: can we finally kill off CONFIG_FS_DAX_LIMITED
Date: Mon, 23 Aug 2021 13:21:03 -0700	[thread overview]
Message-ID: <CAPcyv4jijqrb1O5OOTd5ftQ2Q-5SVwNRM7XMQ+N3MAFxEfvxpA@mail.gmail.com> (raw)
In-Reply-To: <20210823214708.77979b3f@thinkpad>

On Mon, Aug 23, 2021 at 12:47 PM Gerald Schaefer
<gerald.schaefer@linux.ibm.com> wrote:
>
> On Mon, 23 Aug 2021 16:05:46 +0200
> Gerald Schaefer <gerald.schaefer@linux.ibm.com> wrote:
>
> > On Fri, 20 Aug 2021 07:43:40 +0200
> > Christoph Hellwig <hch@lst.de> wrote:
> >
> > > Hi all,
> > >
> > > looking at the recent ZONE_DEVICE related changes we still have a
> > > horrible maze of different code paths.  I already suggested to
> > > depend on ARCH_HAS_PTE_SPECIAL for ZONE_DEVICE there, which all modern
>
> Oh, we do have PTE_SPECIAL, actually that took away the last free bit
> in the pte. So, if there is a chance that ZONE_DEVICE would depend
> on PTE_SPECIAL instead of PTE_DEVMAP, we might be back in the game
> and get rid of that CONFIG_FS_DAX_LIMITED.

So PTE_DEVMAP is primarily there to coordinate the
get_user_pages_fast() path, and even there it's usage can be
eliminated in favor of PTE_SPECIAL. I started that effort [1], but
need to rebase on new notify_failure infrastructure coming from Ruan
[2]. So I think you are not in the critical path until I can get the
PTE_DEVMAP requirement out of your way.

[1]: https://lore.kernel.org/r/161604050866.1463742.7759521510383551055.stgit@dwillia2-desk3.amr.corp.intel.com

[2]: https://lore.kernel.org/r/20210730085245.3069812-1-ruansy.fnst@fujitsu.com

  reply	other threads:[~2021-08-23 20:21 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-20  5:43 can we finally kill off CONFIG_FS_DAX_LIMITED Christoph Hellwig
2021-08-20 15:41 ` Dan Williams
2021-08-20 15:41   ` Dan Williams
2021-08-20 17:42   ` Dan Williams
2021-08-20 17:42     ` Dan Williams
2021-08-20 19:03     ` Gerald Schaefer
2021-08-24 14:17     ` Joao Martins
2021-08-23 14:05 ` Gerald Schaefer
2021-08-23 19:47   ` Gerald Schaefer
2021-08-23 20:21     ` Dan Williams [this message]
2021-08-23 20:21       ` Dan Williams
2021-08-24 14:09       ` Joao Martins
2021-08-24 14:53         ` Dan Williams
2021-08-24 14:53           ` Dan Williams
2021-08-24 18:24           ` Gerald Schaefer
2021-08-24 18:44             ` Dan Williams
2021-08-24 18:44               ` Dan Williams
2021-10-14 23:04               ` Jason Gunthorpe
2021-10-15  0:22                 ` Joao Martins
2021-10-18 23:30                   ` Jason Gunthorpe
2021-10-19  4:26                     ` Dan Williams
2021-10-19 14:20                       ` Jason Gunthorpe
2021-10-19 15:20                         ` Joao Martins
2021-10-19 15:38                         ` Felix Kuehling
2021-10-19 17:38                         ` Dan Williams
2021-10-19 17:54                           ` Jason Gunthorpe
2021-08-24  6:49   ` David Hildenbrand

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=CAPcyv4jijqrb1O5OOTd5ftQ2Q-5SVwNRM7XMQ+N3MAFxEfvxpA@mail.gmail.com \
    --to=dan.j.williams@intel.com \
    --cc=borntraeger@de.ibm.com \
    --cc=gerald.schaefer@linux.ibm.com \
    --cc=gor@linux.ibm.com \
    --cc=hca@linux.ibm.com \
    --cc=hch@lst.de \
    --cc=linux-s390@vger.kernel.org \
    --cc=nvdimm@lists.linux.dev \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.