On 9/19/22 05:20, Miklos Szeredi wrote:
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
Miklos, does this mean that FUSE servers shouldn't bother setting
PR_SET_IO_FLUSHER? Are there any benefits to setting it explicitly or
detriments to not setting it?
