Nicholas Piggin [npig...@gmail.com] wrote: > cp_abort is only required or user windows, because kernel context > must not be preempted between a copy/paste pair.
Yes, that is a good optimization. > > Without this patch, the init task gets used_vas set when it runs > the nx842_powernv_init initcall, which opens windows for kernel > usage. > > used_vas is then never cleared anywhere, so it gets propagated > into all other tasks. It's a property of the address space, so it > should really be cleared when a new mm is created (or in dup_mmap > if the mmaps are marked as VM_DONTCOPY). For now we seem to have > no such driver, so leave that for another patch. If the parent process has the paste address mapped, the child inherits those mappings - so we can't clear the ->used_vas in a process until it has unmapped all the send windows right? If VM_DONCOPY is set, then we can clear it. > > Cc: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com> > Signed-off-by: Nicholas Piggin <npig...@gmail.com> Reviewed-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
