From: Christoph Hellwig <hch@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>,
Jane Chu <jane.chu@oracle.com>,
Vishal L Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
"Weiny, Ira" <ira.weiny@intel.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Linux NVDIMM <nvdimm@lists.linux.dev>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 0/3] dax: clear poison on the fly along pwrite
Date: Thu, 16 Sep 2021 08:11:44 +0100 [thread overview]
Message-ID: <YULuMO86NrQAPcpf@infradead.org> (raw)
In-Reply-To: <CAPcyv4jaCiSXU61gsQTaoN_cdDTDMvFSfMYfBz2yLKx11fdwOQ@mail.gmail.com>
On Wed, Sep 15, 2021 at 01:27:47PM -0700, Dan Williams wrote:
> > Yeah, Christoph suggested that we make the clearing operation explicit
> > in a related thread a few weeks ago:
> > https://lore.kernel.org/linux-fsdevel/YRtnlPERHfMZ23Tr@infradead.org/
>
> That seemed to be tied to a proposal to plumb it all the way out to an
> explicit fallocate() mode, not make it a silent side effect of
> pwrite().
Yes.
> >
> > Each of the dm drivers has to add their own ->clear_poison operation
> > that remaps the incoming (sector, len) parameters as appropriate for
> > that device and then calls the lower device's ->clear_poison with the
> > translated parameters.
> >
> > This (AFAICT) has already been done for dax_zero_page_range, so I sense
> > that Dan is trying to save you a bunch of code plumbing work by nudging
> > you towards doing s/dax_clear_poison/dax_zero_page_range/ to this series
> > and then you only need patches 2-3.
>
> Yes, but it sounds like Christoph was saying don't overload
> dax_zero_page_range(). I'd be ok splitting the difference and having a
> new fallocate clear poison mode map to dax_zero_page_range()
> internally.
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.
>
> >
> > > BTW, our customer doesn't care about creating dax volume thru DM, so.
> >
> > They might not care, but anything going upstream should work in the
> > general case.
>
> Agree.
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.
next prev parent reply other threads:[~2021-09-16 7:12 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 [this message]
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
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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