From: Borislav Petkov <bp@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
Christoph Hellwig <hch@lst.de>, "H. Peter Anvin" <hpa@zytor.com>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
Jerome Glisse <j.glisse@gmail.com>,
markk@clara.co.uk, Joerg Roedel <jroedel@suse.de>,
lkml <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [BUG] Devices breaking due to CONFIG_ZONE_DEVICE
Date: Sun, 24 Jan 2016 10:40:56 +0100 [thread overview]
Message-ID: <20160124094056.GA27266@pd.tnic> (raw)
In-Reply-To: <CAPcyv4ivKNb2=505ytkVMbmOd=49da1EsHoG=Di60XJyoQTs8g@mail.gmail.com>
+ linux-mm
On Fri, Jan 22, 2016 at 10:15:17PM -0800, Dan Williams wrote:
> On Fri, Jan 22, 2016 at 9:47 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> > On Fri, Jan 22, 2016 at 8:46 PM, Sudip Mukherjee
> > <sudipm.mukherjee@gmail.com> wrote:
> >> Hi All,
> >> Commit 033fbae988fc ("mm: ZONE_DEVICE for "device memory"") has
> >> introduced CONFIG_ZONE_DEVICE while sacrificing CONFIG_ZONE_DMA.
> >> Distributions like Ubuntu has started enabling CONFIG_ZONE_DEVICE and
> >> thus breaking parallel port. Please have a look at
> >> https://bugzilla.kernel.org/show_bug.cgi?id=110931 for the bug report.
> >>
> >> Apart from parallel port I can see some sound drivers will also break.
> >>
> >> Now what is the possible solution for this?
> >
> > The tradeoff here is enabling direct-I/O for persistent memory vs
> > support for legacy devices.
> >
> > One possible solution is to alias ZONE_DMA and ZONE_DEVICE. At early
> > boot if pmem is detected disable these legacy devices, or the reverse
> > disable DMA to persistent memory if a legacy device is detected. The
> > latter is a bit harder to do as I think we would want to make the
> > decision early during memory init before we would know if any parallel
> > ports or ISA sound cards are present.
>
> ...another option that might be cleaner is to teach GFP_DMA to get
> memory from a different mechanism. I.e. don't use the mm-zone
> infrastructure to organize that small 16MB pool of memory.
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix ImendA?rffer, Jane Smithard, Graham Norton, HRB 21284 (AG NA 1/4 rnberg)
--
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
Christoph Hellwig <hch@lst.de>, "H. Peter Anvin" <hpa@zytor.com>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
Jerome Glisse <j.glisse@gmail.com>,
markk@clara.co.uk, Joerg Roedel <jroedel@suse.de>,
lkml <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [BUG] Devices breaking due to CONFIG_ZONE_DEVICE
Date: Sun, 24 Jan 2016 10:40:56 +0100 [thread overview]
Message-ID: <20160124094056.GA27266@pd.tnic> (raw)
In-Reply-To: <CAPcyv4ivKNb2=505ytkVMbmOd=49da1EsHoG=Di60XJyoQTs8g@mail.gmail.com>
+ linux-mm
On Fri, Jan 22, 2016 at 10:15:17PM -0800, Dan Williams wrote:
> On Fri, Jan 22, 2016 at 9:47 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> > On Fri, Jan 22, 2016 at 8:46 PM, Sudip Mukherjee
> > <sudipm.mukherjee@gmail.com> wrote:
> >> Hi All,
> >> Commit 033fbae988fc ("mm: ZONE_DEVICE for "device memory"") has
> >> introduced CONFIG_ZONE_DEVICE while sacrificing CONFIG_ZONE_DMA.
> >> Distributions like Ubuntu has started enabling CONFIG_ZONE_DEVICE and
> >> thus breaking parallel port. Please have a look at
> >> https://bugzilla.kernel.org/show_bug.cgi?id=110931 for the bug report.
> >>
> >> Apart from parallel port I can see some sound drivers will also break.
> >>
> >> Now what is the possible solution for this?
> >
> > The tradeoff here is enabling direct-I/O for persistent memory vs
> > support for legacy devices.
> >
> > One possible solution is to alias ZONE_DMA and ZONE_DEVICE. At early
> > boot if pmem is detected disable these legacy devices, or the reverse
> > disable DMA to persistent memory if a legacy device is detected. The
> > latter is a bit harder to do as I think we would want to make the
> > decision early during memory init before we would know if any parallel
> > ports or ISA sound cards are present.
>
> ...another option that might be cleaner is to teach GFP_DMA to get
> memory from a different mechanism. I.e. don't use the mm-zone
> infrastructure to organize that small 16MB pool of memory.
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
next prev parent reply other threads:[~2016-01-24 9:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-23 4:46 [BUG] Devices breaking due to CONFIG_ZONE_DEVICE Sudip Mukherjee
2016-01-23 5:47 ` Dan Williams
2016-01-23 6:15 ` Dan Williams
2016-01-24 9:40 ` Borislav Petkov [this message]
2016-01-24 9:40 ` Borislav Petkov
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=20160124094056.GA27266@pd.tnic \
--to=bp@suse.de \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=hch@lst.de \
--cc=hpa@zytor.com \
--cc=j.glisse@gmail.com \
--cc=jroedel@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=markk@clara.co.uk \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=riel@redhat.com \
--cc=sudipm.mukherjee@gmail.com \
/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.