On Sun, 18 Sept 2022 at 13:03, Nikolaus Rath <Nikolaus@xxxxxxxx> wrote: > > Hi, > > Should the FUSE kernel driver perhaps set PR_SET_IO_FLUSHER for the FUSE > userspace process daemon when a connection is opened? > > If I understand correctly, this is necessary to avoid a deadlocks if the > kernel needs to reclaim memory that has to be written back through FUSE. The fuse kernel driver is careful to avoid such deadlocks. When memory reclaim happens, it copies data to temporary buffers and immediately finishes the reclaim from the memory management subsystem's point of view. The temp buffers are then sent to userspace and written back without having to worry about deadlocks. There are lots of details missing from the above description, but this is the essence of the writeback deadlock avoidance. Thanks, Miklos
