* Andrea Arcangeli [2012-06-07 12:33:55 +0200]: > I guess if Xen can't be updated to handle an atomic64_read on a pmd in > the guest,
I'm not sure if it makes a difference, but just in case: I observed the problem in a dom0. > we can add a pmd_read paravirt op? Or if we don't want to > break the paravirt interface a loop like gup_fast with irq disabled > should also work but looping + local_irq_disable()/enable() sounded > worse and more complex than a atomic64_read (gup fast already disables > irqs because it doesn't hold the mmap_sem so it's a different cost > looping there). AFIK Xen disables THP during boot, so a check on THP > being enabled and falling back in the THP=n version of > pmd_read_atomic, would also be safe, but it's not so nice to do it > with a runtime check. > > Thanks, > Andrea -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
