On 13/9/25 23:52, Arnd Bergmann wrote: Hi Arnd! Thanks for your reply.
Like most other machines, this one is probably fine with a combination of a custom LOWMEM_SIZE setting and using zram-highmem, even if we end up removing support for highmem page cache.
Good shout - I'm now testing a 2G/2G split which allows for 1536MiB lowmem. I know that's a somewhat aggressive setting for userspace, so we'll see if anything breaks. I read Rasbian shipped similar kernels and had issues with Wine, though that's not a common use case on PowerPC ^^
The smaller devices are probable getting problematic sooner, 96MB in the Wii is already really tight and this only gets worse over time.
The maintainer of that downstream claims to be able to boot modern text-mode distros on the GameCube' 24MB, which I find really impressive!
Just to be clear: there is no general 32-bit deprecation going on. When I talked about phasing out 32-bit platforms over time, that is purely going to be those that have no users left, or the few ones that are causing more work than they are worth. E.g. The ppc405 ones got removed recently (after many years of discussion) because they were making ppc440 maintenance harder and had no known users. Highmem does get in the way, but unless more -mm folks make a strong argument in favor of removing it all, it's more likely that we'll go with Willy's suggestion of keeping highmem on page cache (anon and file mappings) than just keeling zram, and even that would still work.
That's good to hear. I would like to have the page cache, though I'm still going to try and maximise lowmem as well.
Thanks, Ash
