Re: [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU

[Michal Hocko]

On Tue 11-02-20 16:28:39, Linus Torvalds wrote:
> On Tue, Feb 11, 2020 at 3:44 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Testing this will be a challenge, but the issue was real - a 7GB
> > highmem machine isn't crazy and I expect the inode has become larger
> > since those days.
> 
> Hmm. I would say that in the intening years a 7GB highmem machine has
> indeed become crazy.

Absolutely agreed.

> It used to be something we kind of supported.

And it's been few years since we have been actively discouraging people
from using 32b kernels with a lot of memory. There are bug reports
popping out from time to time but I do not remember any case where using
64b kernel would be a no-go. So my strong suspicion is that people
simply keep their kernels on 32b without a good reason because it tends
to work most of the time until they hit one of the lowmem problems and
they move over to 64b.

> But we really should consider HIGHMEM to be something that is on the
> deprecation list. In this day and age, there is no excuse for running
> a 32-bit kernel with lots of physical memory.
> 
> And if you really want to do that, and have some legacy hardware with
> a legacy use case, maybe you should be using a legacy kernel.
> 
> I'd personally be perfectly happy to start removing HIGHMEM support again.

I wouldn't be opposed at all.
-- 
Michal Hocko
SUSE Labs