From: Christoph Hellwig <hch@infradead.org>
To: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
nvdimm@lists.linux.dev, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, djwong@kernel.org,
dan.j.williams@intel.com, david@fromorbit.com, hch@infradead.org,
jane.chu@oracle.com
Subject: Re: [PATCH v7 1/8] dax: Use rwsem for dax_{read,write}_lock()
Date: Thu, 14 Oct 2021 23:30:03 -0700 [thread overview]
Message-ID: <YWkf63g44Puobxrp@infradead.org> (raw)
In-Reply-To: <20210924130959.2695749-2-ruansy.fnst@fujitsu.com>
On Fri, Sep 24, 2021 at 09:09:52PM +0800, Shiyang Ruan wrote:
> In order to introduce dax holder registration, we need a write lock for
> dax. Because of the rarity of notification failures and the infrequency
> of registration events, it would be better to be a global lock rather
> than per-device. So, change the current lock to rwsem and introduce a
> write lock for registration.
I don't think taking the rw_semaphore everywhere will scale, as
basically any DAX based I/O will take it (in read mode).
So at a minimum we'd need a per-device percpu_rw_semaphore if we want
to go there.
next prev parent reply other threads:[~2021-10-15 6:30 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 13:09 [PATCH v7 0/8] [PATCH v7 0/8] fsdax: introduce fs query to support reflink Shiyang Ruan
2021-09-24 13:09 ` [PATCH v7 1/8] dax: Use rwsem for dax_{read,write}_lock() Shiyang Ruan
2021-10-14 17:48 ` Darrick J. Wong
2021-10-20 5:19 ` Shiyang Ruan
2021-10-15 6:30 ` Christoph Hellwig [this message]
2021-09-24 13:09 ` [PATCH v7 2/8] dax: Introduce holder for dax_device Shiyang Ruan
2021-10-14 18:00 ` Darrick J. Wong
2021-10-20 6:58 ` Shiyang Ruan
2021-09-24 13:09 ` [PATCH v7 3/8] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2021-10-14 18:02 ` Darrick J. Wong
2021-10-15 6:33 ` Christoph Hellwig
2021-09-24 13:09 ` [PATCH v7 4/8] pagemap,pmem: Introduce ->memory_failure() Shiyang Ruan
2021-10-14 18:05 ` Darrick J. Wong
2021-10-20 5:25 ` Shiyang Ruan
2021-10-15 6:36 ` Christoph Hellwig
2021-09-24 13:09 ` [PATCH v7 5/8] fsdax: Introduce dax_lock_mapping_entry() Shiyang Ruan
2021-10-14 18:17 ` Darrick J. Wong
2021-09-24 13:09 ` [PATCH v7 6/8] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2021-10-14 19:32 ` Darrick J. Wong
2021-10-20 5:47 ` Shiyang Ruan
2021-09-24 13:09 ` [PATCH v7 7/8] xfs: Implement ->notify_failure() for XFS Shiyang Ruan
2021-10-14 19:21 ` Darrick J. Wong
2021-10-15 6:41 ` Christoph Hellwig
2021-09-24 13:09 ` [PATCH v7 8/8] fsdax: add exception for reflinked files Shiyang Ruan
2021-10-14 19:24 ` Darrick J. Wong
2021-10-15 6:38 ` Christoph Hellwig
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