On Wed, 8 Jul 2015 16:34:56 -0400 Eric B Munson <emunson@xxxxxxxxxx> wrote: > > Quick, possibly dumb question: I've been beating my head against these for > > a little bit, and I can't figure out what's supposed to happen in this > > case: > > > > mlock2(addr, len, MLOCK_ONFAULT); > > munlock2(addr, len, MLOCK_LOCKED); > > > > It looks to me like it will clear VM_LOCKED without actually unlocking any > > pages. Is that the intended result? > > This is not quite right, what happens when you call munlock2(addr, len, > MLOCK_LOCKED); is we call apply_vma_flags(addr, len, VM_LOCKED, false). >From your explanation, it looks like what I said *was* right...what I was missing was the fact that VM_LOCKED isn't set in the first place. So that call would be a no-op, clearing a flag that's already cleared. One other question...if I call mlock2(MLOCK_ONFAULT) on a range that already has resident pages, I believe that those pages will not be locked until they are reclaimed and faulted back in again, right? I suspect that could be surprising to users. Thanks, jon
