From: Dan Williams <firstname.lastname@example.org>
To: Christoph Hellwig <email@example.com>
Cc: "Darrick J. Wong" <firstname.lastname@example.org>,
Jane Chu <email@example.com>,
Vishal L Verma <firstname.lastname@example.org>,
Dave Jiang <email@example.com>,
"Weiny, Ira" <firstname.lastname@example.org>,
Al Viro <email@example.com>,
Matthew Wilcox <firstname.lastname@example.org>, Jan Kara <email@example.com>,
Linux NVDIMM <firstname.lastname@example.org>,
Linux Kernel Mailing List <email@example.com>,
Shiyang Ruan <firstname.lastname@example.org>
Subject: Re: [PATCH 0/3] dax: clear poison on the fly along pwrite
Date: Fri, 17 Sep 2021 12:37:51 -0700 [thread overview]
Message-ID: <CAPcyv4hJZpoJPF5_6F+wUUjVY5fHXbVRsLfVNPSZxiS+7yzV0Q@mail.gmail.com> (raw)
On Fri, Sep 17, 2021 at 5:57 AM Christoph Hellwig <email@example.com> wrote:
> On Thu, Sep 16, 2021 at 11:40:28AM -0700, Dan Williams wrote:
> > > That was my gut feeling. If everyone feels 100% comfortable with
> > > zeroingas the mechanism to clear poisoning I'll cave in. The most
> > > important bit is that we do that through a dedicated DAX path instead
> > > of abusing the block layer even more.
> > ...or just rename dax_zero_page_range() to dax_reset_page_range()?
> > Where reset == "zero + clear-poison"?
> I'd say that naming is more confusing than overloading zero.
Ok, I see Darrick has a better suggestion for the shed color.
> > > I'm really worried about both patartitions on DAX and DM passing through
> > > DAX because they deeply bind DAX to the block layer, which is just a bad
> > > idea. I think we also need to sort that whole story out before removing
> > > the EXPERIMENTAL tags.
> > I do think it was a mistake to allow for DAX on partitions of a pmemX
> > block-device.
> > DAX-reflink support may be the opportunity to start deprecating that
> > support. Only enable DAX-reflink for direct mounting on /dev/pmemX
> > without partitions (later add dax-device direct mounting),
> I think we need to fully or almost fully sort this out.
> Here is my bold suggestions:
> 1) drop no drop the EXPERMINTAL on the current block layer overload
> at all
s/drop no drop/do not drop/?
> 2) add direct mounting of the nvdimm namespaces ASAP. Because all
> the filesystem currently also need the /dev/pmem0 device add a way
> to open the block device by the dax_device instead of our current
> way of doing the reverse
Oh, interesting. I can get on board with that. There's currently no
/dev entry for namespaces. It's either /dev/pmemX, or /dev/daxX.Y as a
child of /sys/bus/nd/devices/namespaceX.Y. However, I see nothing
glaringly wrong with having /dev/daxX.Y always published regardless of
whether /dev/pmemX is also present.
> 3) deprecate DAX support through block layer mounts with a say 2 year
> deprecation period
> 4) add DAX remapping devices as needed
> I'll volunteer to write the initial code for 2). And I think we should
> not allow DAX+reflink on the block device shim at all.
Yeah, I think this can fly.
next prev parent reply other threads:[~2021-09-17 19:38 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 23:31 [PATCH 0/3] dax: clear poison on the fly along pwrite Jane Chu
2021-09-14 23:31 ` [PATCH 1/3] dax: introduce dax_operation dax_clear_poison Jane Chu
2021-11-04 17:53 ` Christoph Hellwig
2021-09-14 23:31 ` [PATCH 2/3] dax: introduce dax_clear_poison to dax pwrite operation Jane Chu
2021-11-04 17:53 ` Christoph Hellwig
2021-09-14 23:31 ` [PATCH 2/3] dax: introduce dax clear poison to page aligned " Jane Chu
2021-09-14 23:31 ` [PATCH 3/3] libnvdimm/pmem: Provide pmem_dax_clear_poison for dax operation Jane Chu
2021-11-04 17:55 ` Christoph Hellwig
2021-11-04 20:27 ` Jane Chu
2021-09-15 4:44 ` [PATCH 0/3] dax: clear poison on the fly along pwrite Dan Williams
2021-09-15 7:22 ` Jane Chu
2021-09-15 16:15 ` Darrick J. Wong
2021-09-15 20:27 ` Dan Williams
2021-09-16 0:05 ` Darrick J. Wong
2021-09-16 7:11 ` Christoph Hellwig
2021-09-16 18:40 ` Dan Williams
2021-09-17 12:53 ` Christoph Hellwig
2021-09-17 15:27 ` Darrick J. Wong
2021-09-17 20:21 ` Dan Williams
2021-09-18 0:07 ` Darrick J. Wong
2021-09-17 19:37 ` Dan Williams [this message]
2021-09-23 20:48 ` Jane Chu
2021-09-23 20:55 ` Jane Chu
2021-09-23 21:42 ` Dan Williams
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