From: Christoph Hellwig <hch@lst.de>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Jan Kara <jack@suse.cz>, Ashok Raj <ashok.raj@intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-rdma@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Joerg Roedel <joro@8bytes.org>,
Dave Chinner <david@fromorbit.com>,
linux-xfs@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
Jeff Moyer <jmoyer@redhat.com>,
Linux API <linux-api@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
David Woodhouse <dwmw2@infradead.org>,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH v7 07/12] dma-mapping: introduce dma_has_iommu()
Date: Fri, 13 Oct 2017 09:09:29 +0200 [thread overview]
Message-ID: <20171013070929.GA26652@lst.de> (raw)
In-Reply-To: <20171009191820.GD15336@obsidianresearch.com>
On Mon, Oct 09, 2017 at 01:18:20PM -0600, Jason Gunthorpe wrote:
> > > If RDMA is driving this need, why not invalidate backing RDMA MRs
> > > instead of requiring a IOMMU to do it? RDMA MR are finer grained and
> > > do not suffer from the re-use problem David W. brought up with IOVAs..
> >
> > Sounds promising. All I want in the end is to be sure that the kernel
> > is enabled to stop any in-flight RDMA at will without asking
> > userspace. Does this require per-RDMA driver opt-in or is there a
> > common call that can be made?
>
> I don't think this has ever come up in the context of an all-device MR
> invalidate requirement. Drivers already have code to invalidate
> specifc MRs, but to find all MRs that touch certain pages and then
> invalidate them would be new code.
The whole point is that we should not need that IFF we provide the
right interface.
If we have a new 'register memory with a lease', the driver (or in fact
probably the umem core for the drivers using it) has the lease associated
with the ib_umem structure, which will just need a backpointer from the
ib_umem to the to the MR to unregister it.
Which might be a good opportunity to break the user MR from the in-kernel
ones and merge it with ib_umem, but that's a different story..
--
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>
next prev parent reply other threads:[~2017-10-13 7:09 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-06 22:35 [PATCH v7 00/12] MAP_DIRECT for DAX RDMA and userspace flush Dan Williams
2017-10-06 22:35 ` [PATCH v7 01/12] mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags Dan Williams
2017-10-06 22:35 ` [PATCH v7 02/12] fs, mm: pass fd to ->mmap_validate() Dan Williams
2017-10-06 22:35 ` [PATCH v7 03/12] fs: introduce i_mapdcount Dan Williams
2017-10-09 3:08 ` Dave Chinner
2017-10-06 22:35 ` [PATCH v7 04/12] fs: MAP_DIRECT core Dan Williams
2017-10-06 22:35 ` [PATCH v7 05/12] xfs: prepare xfs_break_layouts() for reuse with MAP_DIRECT Dan Williams
2017-10-06 22:35 ` [PATCH v7 06/12] xfs: wire up MAP_DIRECT Dan Williams
2017-10-09 3:40 ` Dave Chinner
2017-10-09 17:08 ` Dan Williams
2017-10-09 22:50 ` Dave Chinner
2017-10-06 22:35 ` [PATCH v7 07/12] dma-mapping: introduce dma_has_iommu() Dan Williams
2017-10-06 22:45 ` David Woodhouse
2017-10-06 22:52 ` Dan Williams
2017-10-06 23:10 ` David Woodhouse
2017-10-06 23:15 ` Dan Williams
2017-10-07 11:08 ` David Woodhouse
2017-10-07 23:33 ` Dan Williams
2017-10-06 23:12 ` Dan Williams
2017-10-08 3:45 ` [PATCH v8] dma-mapping: introduce dma_get_iommu_domain() Dan Williams
2017-10-09 10:37 ` Robin Murphy
2017-10-09 17:32 ` Dan Williams
2017-10-10 14:40 ` Raj, Ashok
2017-10-09 18:58 ` [PATCH v7 07/12] dma-mapping: introduce dma_has_iommu() Jason Gunthorpe
2017-10-09 19:05 ` Dan Williams
2017-10-09 19:18 ` Jason Gunthorpe
2017-10-09 19:28 ` Dan Williams
2017-10-10 17:25 ` Jason Gunthorpe
2017-10-10 17:39 ` Dan Williams
2017-10-10 18:05 ` Jason Gunthorpe
2017-10-10 20:17 ` Dan Williams
2017-10-12 18:27 ` Jason Gunthorpe
2017-10-12 20:10 ` Dan Williams
2017-10-13 6:50 ` Christoph Hellwig
2017-10-13 15:03 ` Jason Gunthorpe
2017-10-15 15:14 ` Matan Barak
2017-10-15 15:21 ` Dan Williams
2017-10-13 7:09 ` Christoph Hellwig [this message]
2017-10-06 22:36 ` [PATCH v7 08/12] fs, mapdirect: introduce ->lease_direct() Dan Williams
2017-10-06 22:36 ` [PATCH v7 09/12] xfs: wire up ->lease_direct() Dan Williams
2017-10-09 3:45 ` Dave Chinner
2017-10-09 17:10 ` Dan Williams
2017-10-06 22:36 ` [PATCH v7 10/12] device-dax: " Dan Williams
2017-10-06 22:36 ` [PATCH v7 11/12] IB/core: use MAP_DIRECT to fix / enable RDMA to DAX mappings Dan Williams
2017-10-08 4:02 ` [PATCH v8 1/2] iommu: up-level sg_num_pages() from amd-iommu Dan Williams
2017-10-08 4:04 ` [PATCH v8 2/2] IB/core: use MAP_DIRECT to fix / enable RDMA to DAX mappings Dan Williams
2017-10-08 6:45 ` kbuild test robot
2017-10-08 15:49 ` Dan Williams
2017-10-06 22:36 ` [PATCH v7 12/12] tools/testing/nvdimm: enable rdma unit tests Dan Williams
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=20171013070929.GA26652@lst.de \
--to=hch@lst.de \
--cc=ashok.raj@intel.com \
--cc=dan.j.williams@intel.com \
--cc=darrick.wong@oracle.com \
--cc=david@fromorbit.com \
--cc=dwmw2@infradead.org \
--cc=gregkh@linuxfoundation.org \
--cc=jack@suse.cz \
--cc=jgunthorpe@obsidianresearch.com \
--cc=jmoyer@redhat.com \
--cc=joro@8bytes.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nvdimm@lists.01.org \
--cc=linux-rdma@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=m.szyprowski@samsung.com \
--cc=robin.murphy@arm.com \
--cc=ross.zwisler@linux.intel.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 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).