Hello, this patch series fixes estimate of writeback throughput when device is not fully busy doing writeback. Michael Stapelberg has reported that such workload (e.g. generated by linking) tends to push estimated throughput down to 0 and as a result writeback on the device is practically stalled. The first three patches fix the reported issue, the remaining two patches are unrelated cleanups of problems I've noticed when reading the code. Michael, can you try whether these patches fix the problems you've observed? I cannot trigger the "bandwidth going down" spiral with them anymore. Honza
