Re: [PATCH][1/2] adjust dirty threshold for lowmem-only mappings

Andrew Morton
2005-01-02T20:03:59Z

Jens Axboe <axboe@suse.de> wrote:
>
> > Lifting the artificial lowmem restrictions on blockdev mappings
> > (thereby nuking mapping->gfp_mask altogether) would resolve a number of
> > problems, not that anything making that much sense could ever happen.
>
> It should be lifted for block devices, it doesn't make any sense.

Before we can permit blockdev pagecache to use highmem we must convert
every piece of code which accesses the cache to use kmap/kmap_atomic. If
you grep around for b_data you'll see there are a lot of such places.

Probably the migration could be done on a per-fs basis.