From: "Darrick J. Wong" <djwong@kernel.org>
To: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Dan Williams <dan.j.williams@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
Linux NVDIMM <nvdimm@lists.linux.dev>,
Linux MM <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
david <david@fromorbit.com>, Jane Chu <jane.chu@oracle.com>
Subject: Re: [PATCH v9 02/10] dax: Introduce holder for dax_device
Date: Thu, 20 Jan 2022 18:22:00 -0800 [thread overview]
Message-ID: <20220121022200.GG13563@magnolia> (raw)
In-Reply-To: <76f5ed28-2df9-890e-0674-3ef2f18e2c2f@fujitsu.com>
On Fri, Jan 21, 2022 at 09:26:52AM +0800, Shiyang Ruan wrote:
>
>
> 在 2022/1/20 16:46, Christoph Hellwig 写道:
> > On Wed, Jan 05, 2022 at 04:12:04PM -0800, Dan Williams wrote:
> > > We ended up with explicit callbacks after hch balked at a notifier
> > > call-chain, but I think we're back to that now. The partition mistake
> > > might be unfixable, but at least bdev_dax_pgoff() is dead. Notifier
> > > call chains have their own locking so, Ruan, this still does not need
> > > to touch dax_read_lock().
> >
> > I think we have a few options here:
> >
> > (1) don't allow error notifications on partitions. And error return from
> > the holder registration with proper error handling in the file
> > system would give us that
Hm, so that means XFS can only support dax+pmem when there aren't
partitions in use? Ew.
> > (2) extent the holder mechanism to cover a rangeo
I don't think I was around for the part where "hch balked at a notifier
call chain" -- what were the objections there, specifically? I would
hope that pmem problems would be infrequent enough that the locking
contention (or rcu expiration) wouldn't be an issue...?
> > (3) bite the bullet and create a new stacked dax_device for each
> > partition
> >
> > I think (1) is the best option for now. If people really do need
> > partitions we'll have to go for (3)
>
> Yes, I agree. I'm doing it the first way right now.
>
> I think that since we can use namespace to divide a big NVDIMM into multiple
> pmems, partition on a pmem seems not so meaningful.
I'll try to find out what will happen if pmem suddenly stops supporting
partitions...
--D
>
> --
> Thanks,
> Ruan.
>
>
next prev parent reply other threads:[~2022-01-21 2:22 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-26 14:34 [PATCH v9 00/10] fsdax: introduce fs query to support reflink Shiyang Ruan
2021-12-26 14:34 ` [PATCH v9 01/10] dax: Use percpu rwsem for dax_{read,write}_lock() Shiyang Ruan
2022-01-04 22:44 ` Dan Williams
2022-01-05 17:45 ` Darrick J. Wong
2022-01-06 11:06 ` Shiyang Ruan
2021-12-26 14:34 ` [PATCH v9 02/10] dax: Introduce holder for dax_device Shiyang Ruan
2022-01-05 18:12 ` Darrick J. Wong
2022-01-05 18:23 ` Dan Williams
2022-01-05 18:56 ` Darrick J. Wong
2022-01-05 19:20 ` Dan Williams
2022-01-05 22:47 ` Darrick J. Wong
2022-01-05 23:01 ` Dan Williams
2022-01-05 23:54 ` Darrick J. Wong
2022-01-06 0:12 ` Dan Williams
2022-01-20 8:46 ` Christoph Hellwig
2022-01-21 1:26 ` Shiyang Ruan
2022-01-21 2:22 ` Darrick J. Wong [this message]
2022-01-21 7:17 ` Christoph Hellwig
2022-02-15 21:51 ` Dan Williams
2021-12-26 14:34 ` [PATCH v9 03/10] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2021-12-26 14:34 ` [PATCH v9 04/10] pagemap,pmem: Introduce ->memory_failure() Shiyang Ruan
2022-01-05 19:06 ` Darrick J. Wong
2021-12-26 14:34 ` [PATCH v9 05/10] fsdax: fix function description Shiyang Ruan
2022-01-05 17:50 ` Darrick J. Wong
2022-01-20 8:47 ` Christoph Hellwig
2021-12-26 14:34 ` [PATCH v9 06/10] fsdax: Introduce dax_lock_mapping_entry() Shiyang Ruan
2022-01-04 22:55 ` Dan Williams
2021-12-26 14:34 ` [PATCH v9 07/10] mm: move pgoff_address() to vma_pgoff_address() Shiyang Ruan
2022-01-20 8:47 ` Christoph Hellwig
2021-12-26 14:34 ` [PATCH v9 08/10] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2022-01-20 8:55 ` Christoph Hellwig
2021-12-26 14:34 ` [PATCH v9 09/10] xfs: Implement ->notify_failure() for XFS Shiyang Ruan
2022-01-05 18:53 ` Darrick J. Wong
2022-01-05 21:17 ` Dan Williams
2021-12-26 14:34 ` [PATCH v9 10/10] fsdax: set a CoW flag when associate reflink mappings Shiyang Ruan
2022-01-20 8:59 ` Christoph Hellwig
2022-01-21 2:33 ` Shiyang Ruan
2022-01-21 7:16 ` Christoph Hellwig
2022-01-21 8:34 ` Shiyang Ruan
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