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charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 41B5F140011 X-Stat-Signature: 8qy4kezf5chth48tq3bf7iq3c6hcwtaa X-Rspam-User: X-HE-Tag: 1760589605-350417 X-HE-Meta: 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 GDH59ofU kR/axlz76/mloBOVWOCLRnZ/xLq+49j/aNScKt5Y6Na+Nv6I8LTYv9nA3ngG30didC2NEJH56IOu/ZMSImREJ1BgzhwErHZuIT4PpJNpitDG5mgei/qHlRxrb8Rk86uPaohNvJUNmTo/DUVohBV9H5YOWxx8NUf/K3JOPGJKyDbn9wrmjzc1ac8rCrpH6zsvqVGE4vc+BLIvyCJA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Oct 16, 2025 at 07:49:20AM +1100, Dave Chinner wrote: > On Wed, Oct 15, 2025 at 03:27:15PM +0900, Christoph Hellwig wrote: > > The relatively low minimal writeback size of 4MiB leads means that > > written back inodes on rotational media are switched a lot. Besides > > introducing additional seeks, this also can lead to extreme file > > fragmentation on zoned devices when a lot of files are cached relative > > to the available writeback bandwidth. > > > > Add a superblock field that allows the file system to override the > > default size. > > Hmmm - won't changing this for the zoned rtdev also change behaviour > for writeback on the data device? i.e. upping the minimum for the > normal data device on XFS will mean writeback bandwidth sharing is a > lot less "fair" and higher latency when we have a mix of different > file sizes than it currently is... In theory it is. In practice with a zoned file system the main device is: a) typically only used for metadata b) a fast SSD when not actually on the same device So I think these concerns are valid, but not really worth replacing the simple superblock field with a method to query the value. But I'll write a comment documenting these assumptions as that is useful for future readers of the code. > > -Dave. > -- > Dave Chinner > david@fromorbit.com ---end quoted text---