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From: Matthew Wilcox <willy@infradead.org>
To: Ruan Shiyang <ruansy.fnst@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org, darrick.wong@oracle.com,
	dan.j.williams@intel.com, david@fromorbit.com, hch@lst.de,
	rgoldwyn@suse.de, qi.fuli@fujitsu.com, y-goto@fujitsu.com
Subject: Re: [RFC PATCH 0/8] fsdax: introduce FS query interface to support reflink
Date: Mon, 10 Aug 2020 12:16:57 +0100	[thread overview]
Message-ID: <20200810111657.GL17456@casper.infradead.org> (raw)
In-Reply-To: <9673ed3c-9e42-3d01-000b-b01cda9832ce@cn.fujitsu.com>

On Mon, Aug 10, 2020 at 04:15:50PM +0800, Ruan Shiyang wrote:
> 
> 
> On 2020/8/7 下午9:38, Matthew Wilcox wrote:
> > On Fri, Aug 07, 2020 at 09:13:28PM +0800, Shiyang Ruan wrote:
> > > This patchset is a try to resolve the problem of tracking shared page
> > > for fsdax.
> > > 
> > > Instead of per-page tracking method, this patchset introduces a query
> > > interface: get_shared_files(), which is implemented by each FS, to
> > > obtain the owners of a shared page.  It returns an owner list of this
> > > shared page.  Then, the memory-failure() iterates the list to be able
> > > to notify each process using files that sharing this page.
> > > 
> > > The design of the tracking method is as follow:
> > > 1. dax_assocaite_entry() associates the owner's info to this page
> > 
> > I think that's the first problem with this design.  dax_associate_entry is
> > a horrendous idea which needs to be ripped out, not made more important.
> > It's all part of the general problem of trying to do something on a
> > per-page basis instead of per-extent basis.
> > 
> 
> The memory-failure needs to track owners info from a dax page, so I should
> associate the owner with this page.  In this version, I associate the block
> device to the dax page, so that the memory-failure is able to iterate the
> owners by the query interface provided by filesystem.

No, it doesn't need to track owner info from a DAX page.  What it needs to
do is ask the filesystem.

  reply	other threads:[~2020-08-10 11:17 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-07 13:13 [RFC PATCH 0/8] fsdax: introduce FS query interface to support reflink Shiyang Ruan
2020-08-07 13:13 ` [RFC PATCH 1/8] fs: introduce get_shared_files() for dax&reflink Shiyang Ruan
2020-08-07 16:15   ` Darrick J. Wong
2020-08-10  8:07     ` Ruan Shiyang
2020-08-07 13:13 ` [RFC PATCH 2/8] fsdax, mm: track files sharing dax page for memory-failure Shiyang Ruan
2020-08-07 13:13 ` [RFC PATCH 3/8] fsdax: introduce dax_copy_edges() for COW Shiyang Ruan
2020-08-07 13:13 ` [RFC PATCH 4/8] fsdax: copy data before write Shiyang Ruan
2020-08-07 13:13 ` [RFC PATCH 5/8] fsdax: replace mmap entry in case of CoW Shiyang Ruan
2020-08-07 13:13 ` [RFC PATCH 6/8] fsdax: dedup file range to use a compare function Shiyang Ruan
2020-08-07 13:13 ` [RFC PATCH 7/8] fs/xfs: handle CoW for fsdax write() path Shiyang Ruan
2020-08-07 13:13 ` [RFC PATCH 8/8] fs/xfs: support dedupe for fsdax Shiyang Ruan
2020-08-07 13:38 ` [RFC PATCH 0/8] fsdax: introduce FS query interface to support reflink Matthew Wilcox
2020-08-10  8:15   ` Ruan Shiyang
2020-08-10 11:16     ` Matthew Wilcox [this message]
2020-08-10 21:10       ` Dave Chinner

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