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

[Matthew Wilcox]

On Tue, Feb 11, 2020 at 04:28:39PM -0800, 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.
> 
> It used to be something we kind of supported.
> 
> 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.

Do we have a use case where people want to run modern 32-bit guest kernels
with more than 896MB of memory to support some horrendous legacy app?
Or is our 32-bit compat story good enough that nobody actually does this?
(Contrariwise, maybe those people are also fine with running a ten year
old kernel because a `uname -r` starting with '3' breaks said app)