> On Jun 22, 2021, at 11:07 AM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Jun 22, 2021 at 11:05 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: >> >> Huh? Last I checked, the fault_in_readable actually read a byte from >> the page. It has to wait for the read to complete before that can >> happen. > > Yeah, we don't have any kind of async fault-in model. > > I'm not sure how that would even look. I don't think it would > necessarily be *impossible* (special marker in the exception table to > let the fault code know that this is a "prepare" fault), but it would > be pretty challenging. I did send an RFC some time ago for “prepare” fault, but it the RFC requires some more work. https://lore.kernel.org/lkml/20210225072910.2811795-1-namit@xxxxxxxxxx/
