Re: [PATCH 1/1] mm: bdi: Initialize bdi_min_ratio when bdi unregister

[Matthew Wilcox]

On Thu, Oct 21, 2021 at 04:16:52AM -0700, Christoph Hellwig wrote:
> On Fri, Oct 22, 2021 at 01:19:43AM +0900, Manjong Lee wrote:
> > Because when sdcard is removed, bdi_min_ratio value will remain.
> > Currently, the only way to reset bdi_ min_ratio is to reboot.
> 
> But bdis that are unregistered are never re-registered.  What is
> the problem you're trying to solve?

The global bdi_min_ratio needs to be adjusted.  See
bdi_set_min_ratio() in mm/page-writeback.c.