Re: [PATCH 00/13] Parallelizing filesystem writeback

Christoph Hellwig
2025-06-03T14:05:17Z

On Tue, Jun 03, 2025 at 04:04:45PM +0200, Christoph Hellwig wrote:
> On Tue, Jun 03, 2025 at 07:22:18PM +0530, Anuj gupta wrote:
> > > A mount option is about the worst possible interface for behavior
> > > that depends on file system implementation and possibly hardware
> > > chacteristics. This needs to be set by the file systems, possibly
> > > using generic helpers using hardware information.
> >
> > Right, that makes sense. Instead of using a mount option, we can
> > introduce generic helpers to initialize multiple writeback contexts
> > based on underlying hardware characteristics — e.g., number of CPUs or
> > NUMA topology. Filesystems like XFS and EXT4 can then call these helpers
> > during mount to opt into parallel writeback in a controlled way.
>
> Yes. A mount option might still be useful to override this default,
> but it should not be needed for the normal use case.

.. actually a sysfs file on the bdi is probably the better interface
for the override than a mount option.