From: "Ruan, Shiyang" <ruansy.fnst@cn.fujitsu.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"darrick.wong@oracle.com" <darrick.wong@oracle.com>,
"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"david@fromorbit.com" <david@fromorbit.com>,
"hch@lst.de" <hch@lst.de>, "rgoldwyn@suse.de" <rgoldwyn@suse.de>,
"Qi, Fuli" <qi.fuli@fujitsu.com>,
"Gotou, Yasunori" <y-goto@fujitsu.com>
Subject: 回复: Re: [RFC PATCH 0/8] dax: Add a dax-rmap tree to support reflink
Date: Tue, 28 Apr 2020 06:09:47 +0000 [thread overview]
Message-ID: <em33c55fa5-15ca-4c46-8c27-6b0300fa4e51@g08fnstd180058> (raw)
In-Reply-To: <20200427122836.GD29705@bombadil.infradead.org>
在 2020/4/27 20:28:36, "Matthew Wilcox" <willy@infradead.org> 写道:
>On Mon, Apr 27, 2020 at 04:47:42PM +0800, Shiyang Ruan wrote:
>> This patchset is a try to resolve the shared 'page cache' problem for
>> fsdax.
>>
>> In order to track multiple mappings and indexes on one page, I
>> introduced a dax-rmap rb-tree to manage the relationship. A dax entry
>> will be associated more than once if is shared. At the second time we
>> associate this entry, we create this rb-tree and store its root in
>> page->private(not used in fsdax). Insert (->mapping, ->index) when
>> dax_associate_entry() and delete it when dax_disassociate_entry().
>
>Do we really want to track all of this on a per-page basis? I would
>have thought a per-extent basis was more useful. Essentially, create
>a new address_space for each shared extent. Per page just seems like
>a huge overhead.
>
Per-extent tracking is a nice idea for me. I haven't thought of it
yet...
But the extent info is maintained by filesystem. I think we need a way
to obtain this info from FS when associating a page. May be a bit
complicated. Let me think about it...
--
Thanks,
Ruan Shiyang.
next prev parent reply other threads:[~2020-04-28 6:10 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-27 8:47 [RFC PATCH 0/8] dax: Add a dax-rmap tree to support reflink Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 1/8] fs/dax: Introduce dax-rmap btree for reflink Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 2/8] mm: add dax-rmap for memory-failure and rmap Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 3/8] fs/dax: Introduce dax_copy_edges() for COW Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 4/8] fs/dax: copy data before write Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 5/8] fs/dax: replace mmap entry in case of CoW Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 6/8] fs/dax: dedup file range to use a compare function Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 7/8] fs/xfs: handle CoW for fsdax write() path Shiyang Ruan
2020-04-27 8:47 ` [RFC PATCH 8/8] fs/xfs: support dedupe for fsdax Shiyang Ruan
2020-04-27 12:28 ` [RFC PATCH 0/8] dax: Add a dax-rmap tree to support reflink Matthew Wilcox
2020-04-28 6:09 ` Ruan, Shiyang [this message]
2020-04-28 6:43 ` 回复: " Dave Chinner
2020-04-28 9:32 ` Ruan Shiyang
2020-04-28 11:16 ` Matthew Wilcox
2020-04-28 11:24 ` Dave Chinner
2020-04-28 15:37 ` Darrick J. Wong
2020-04-28 22:02 ` Dave Chinner
2020-06-04 7:37 ` Ruan Shiyang
2020-06-04 14:51 ` Darrick J. Wong
2020-06-05 1:30 ` Dave Chinner
2020-06-05 2:30 ` Ruan Shiyang
2020-06-05 2:11 ` Ruan Shiyang
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