(cc Kees, LAKML) https://lkml.kernel.org/r/69fa6015256613ed10aee996e181ebd4%40horotw.com On Mon, 15 Jan 2024 at 21:46, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > ... > Yeah, I don't know either. Outside my scope of expertise. > > I received a suggestion off-list that we only do the PMD alignment on > 64-bit, which seems quite reasonable to me. After all, I don't care > about performance on 32-bit just as much as I don't care about security > on 32-bit. > For context, the culprit is commit 1854bc6e2420472676c5c90d3d6b15f6cd640e40 Author: William Kucharski <william.kucharski@xxxxxxxxxx> Date: Sun Sep 22 08:43:15 2019 -0400 mm/readahead: Align file mappings for non-DAX When we have the opportunity to use PMDs to map a file, we want to follow the same rules as DAX. Signed-off-by: William Kucharski <william.kucharski@xxxxxxxxxx> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> which affects *all* 32-bit architectures not just i686. 32-bit ARM user space is still being deployed widely, even on arm64 Chromebooks running 64-bit kernels (at least up until recently) so unfortunately, we're not quite at the point yet where we can just let it rot.
