On Tue, Jan 14, 2025 at 01:29:04PM +0000, Christian Loehle wrote: > On 1/14/25 12:47, Florian Schmaus wrote: > > While the rebalance thread is isually not compute bound, it does cause > > s/isually/usually > > > a considerable amount of I/O. Since "reducing" the nice level from 0 > > to 19, also implicitly reduces the threads best-effort I/O scheduling > > class level from 4 to 7, the reblance thread's I/O will be depriotized > > s/depriotized/deprioritized/ > > > over normal I/O. > > > > Furthermore, we set the rebalance thread's scheduling class to BATCH, > > which means that it will potentially receive a higher scheduling > > latency. Making room for threads that need a low > > schedulinglatency (e.g., interactive onces). > > s/schedulinglatency/ > I know nothing about bcachefs internals, but could this also be a problem? > The rebalance thread might not run for O(second) or so?
Actually that is a concern - six locks don't have priority inheritence. For that matter, standard mutexes and rw semaphores don't either, just the RT variants, which seems questionable to me...
