On Fri, Nov 07, 2025 at 02:54:42PM +0530, Kundan Kumar wrote: > Predicting the Allocation Group (AG) for aged filesystems and passing > this information to per-AG writeback threads appears to be a complex > task.
Yes. But in the end aged file systems are what will see most usage. Fresh file systems look nice in benchmarks, but they aren't what users will mostly deal with. > To segregate these I/O requests by AG, it is necessary to associate > AG-specific information with the pages/folios in the page cache. Two > possible approaches are: > (1) storing AG information in the folio->private field, or > (2) introducing new markers in the xarray to track AG-specific data. > > The AG-affined writeback thread processes specific pages from the page > cache marked for its AG. Is this a viable approach, or are there > alternative solutions that could be more effective? Or maybe the per-AG scheme isn't that great after all and we just need some other simple sharding scheme? Of course lock contention will be nicer on a per-AG basis, but as you found out actually mapping high-level writeback to AGs is pretty hard. _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
