On Tue, Nov 14, 2017 at 11:00:20PM -0800, Dave Hansen wrote: > On 11/14/2017 07:44 PM, Matthew Wilcox wrote: > > We don't need to kmap in order to access MOVABLE allocations. kmap is > > only needed for HIGHMEM allocations. So there's nothing wrong with ext4 > > or set_bh_page(). > > Yeah, it's definitely not _buggy_. > > Although, I do wonder what we should do about these for XPFO. Should we > just stick a kmap() in there and comment it? What we really need is a > mechanism to say "use this as a kernel page" and "stop using this as a > kernel page". kmap() does that... kinda. It's not a perfect fit, but > it's pretty close.
It'd be kind of funny if getting XPFO working better means improving how well Linux runs on 32-bit machines with HIGHMEM. I think there's always going to be interest in those -- ARM developed 36 bit physmem before biting the bullet and going to arm64. Maybe OpenRISC will do that next ;-)
