On Thu, 15 Feb 2007 23:08:02 -0800 Jeremy Fitzhardinge <jeremy at goop.org> wrote: > Andrew Morton wrote: > > This won't work when CONFIG_PREEMPT=y. The pagefault handler will see > > in_atomic() and will scram. > > > > Is there some other way to get the pagetable populated for the address > range? > If you really need to run atomically, that gets ugly. Even of one were to run handle_mm_fault() by hand, it still needs to allocate memory. Two ugly options might be: a) touch all the pages, then go atomic, then touch them all again. If one of them faults (ie: you raced with swapout) then go back and try again. Obviously susceptible to livelocking. b) Do get_user_pages() against all the pages, then go atomic, then do put_page() against them all. Of course, they can immediately get swapped out. But that function's already racy against swapout and I guess it works OK. I don't have clue what it is actually trying to do, so I'm guessing madly here.
