On 8/11/25 21:44, Bart Van Assche wrote: > On 8/11/25 3:52 AM, Christoph Hellwig wrote: >> On Thu, Aug 07, 2025 at 11:48:38AM +0800, Chao Yu wrote: >>> This patch introduces a new sysfs entry /sys/fs/f2fs/<disk>/flush_policy >>> in order to tune performance of f2fs data flush flow. >>> >>> For example, checkpoint will use REQ_FUA to persist CP metadata, however, >>> some kind device has bad performance on REQ_FUA command, result in that >>> checkpoint being blocked for long time, w/ this sysfs entry, we can give >>> an option to use REQ_PREFLUSH command instead of REQ_FUA during checkpoint, >>> it can help to mitigate long latency of checkpoint. >> >> That's and odd place to deal with this. If that's a real issue it >> should be a block layer tweak to disable FUA, potentially with a quirk >> entry in the driver to disable it rather than having to touch a file >> system sysfs attribute. > > Chao, two years ago Christoph already suggested to integrate this > functionality in the UFS driver. From > https://lore.kernel.org/linux-scsi/Y+NCDzvuLJYGwyhC@xxxxxxxxxxxxx/: > "Please add quirks for the actually affected devices, and do not > block fua for an entire transport." > > See also the ufs_fixups[] array in drivers/ufs/core/ufshcd.c. Bart, thank you for letting me know the history and decision there. I had a qemu option here to resolve my current issue, thanks. Thanks, > > Bart.
