On 01/22, Alex Thorlton wrote: > > On Wed, Jan 22, 2014 at 08:43:27PM +0100, Oleg Nesterov wrote: > > On 01/22, Oleg Nesterov wrote: > > > > > > On 01/22, Alex Thorlton wrote: > > > > > + case PR_SET_THP_DISABLE: > > > > > + case PR_GET_THP_DISABLE: > > > > > + down_write(&me->mm->mmap_sem); > > > > > + if (option == PR_SET_THP_DISABLE) { > > > > > + if (arg2) > > > > > + me->mm->def_flags |= VM_NOHUGEPAGE; > > > > > + else > > > > > + me->mm->def_flags &= ~VM_NOHUGEPAGE; > > > > > + } else { > > > > > + error = !!(me->mm->flags && VM_NOHUGEPAGE); > > > > > > > > Should be: > > > > > > > > error = !!(me->mm->def_flags && VM_NOHUGEPAGE); > > > > > > No, we need to return 1 if this bit is set ;) > > > > Damn, you are right of course, we need "&". I didn't notice "&&" > > in the patch I sent and misunderstood your "&&" above ;) Sorry. > > Actually, I didn't catch that either! Looking at it, though, we > definitely do want bitwise AND here, not logical. > > However, what I was originally referring to is: Shouldn't we be > checking mm->***def_flags*** for the VM_NOHUGEPAGE bit, as opposed > to mm->flags? i.e. I think we want this: > > error = !!(me->mm->def_flags & VM_NOHUGEPAGE);
Damn, of course you are right. I misunderstood you twice. But so far I'm afraid this idea can't work anyway, although lets wait for reply from s390 maintainers. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/