linux-arm.git - Russell King's ARM Linux kernel tree

Age	Commit message (Collapse)	Author
2025-03-03	xfs: support write life time based data placement	Hans Holmberg
	Add a file write life time data placement allocation scheme that aims to minimize fragmentation and thereby to do two things: a) separate file data to different zones when possible. b) colocate file data of similar life times when feasible. To get best results, average file sizes should align with the zone capacity that is reported through the XFS_IOC_FSGEOMETRY ioctl. This improvement in data placement efficiency reduces the number of blocks requiring relocation by GC, and thus decreases overall write amplification. The impact on performance varies depending on how full the file system is. For RocksDB using leveled compaction, the lifetime hints can improve throughput for overwrite workloads at 80% file system utilization by ~10%, but for lower file system utilization there won't be as much benefit in application performance as there is less need for garbage collection to start with. Lifetime hints can be disabled using the nolifetime mount option. Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
2025-03-03	xfs: implement zoned garbage collection	Christoph Hellwig
	RT groups on a zoned file system need to be completely empty before their space can be reused. This means that partially empty groups need to be emptied entirely to free up space if no entirely free groups are available. Add a garbage collection thread that moves all data out of the least used zone when not enough free zones are available, and which resets all zones that have been emptied. To find empty zone a simple set of 10 buckets based on the amount of space used in the zone is used. To empty zones, the rmap is walked to find the owners and the data is read and then written to the new place. To automatically defragment files the rmap records are sorted by inode and logical offset. This means defragmentation of parallel writes into a single zone happens automatically when performing garbage collection. Because holding the iolock over the entire GC cycle would inject very noticeable latency for other accesses to the inodes, the iolock is not taken while performing I/O. Instead the I/O completion handler checks that the mapping hasn't changed over the one recorded at the start of the GC cycle and doesn't update the mapping if it change. Co-developed-by: Hans Holmberg <hans.holmberg@wdc.com> Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>