Hi, Christoph. On 2023/11/26 20:47, Christoph Hellwig wrote: > Back in the days when a single bio could only be filled to the hardware > limits, and we scheduled a work item for each bio completion, chaining > multiple bios for a single ioend made a lot of sense to reduce the number > of completions. But these days bios can be filled until we reach the > number of vectors or total size limit, which means we can always fit at > least 1 megabyte worth of data in the worst case, but usually a lot more > due to large folios. The only thing bio chaining is buying us now is > to reduce the size of the allocation from an ioend with an embedded bio > into a plain bio, which is a 52 bytes differences on 64-bit systems. > > This is not worth the added complexity, so remove the bio chaining and > only use the bio embedded into the ioend. This will help to simplify > further changes to the iomap writeback code. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> A nice cleanup! I'm just a little curious about the writeback performance impact of this patch. Do you have any actual test data on xfs? Thanks, Yi.
