On Tue, Jul 29, 2025 at 12:13:42PM -0400, Tony Battersby wrote: > Improve writeback performance to RAID-4/5/6 by aligning writes to stripe > boundaries. This relies on io_opt being set to the stripe size (or > a multiple) when BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE is set. When you say "aligning writes to stripe boundaries", what you actually seem to be doing here is sending writes down once we hit a write stripe boundary, instead of accumulating writes that cross stripe boundaries. Do I understand correctly? If so, the performance gain we see here is presumably from the DM/MD driver not having to split bios that cross boundaries? Further, wouldn't it be simpler to just put a new condition in iomap_can_add_to_ioend() rather than turning iomap_add_to_ioend() into a nested loop?
