Hi, Christoph. On Fri, Apr 23, 2010 at 12:14 AM, Christoph Lameter <cl@xxxxxxxxx> wrote: > On Thu, 22 Apr 2010, Minchan Kim wrote: > >> For further optimization, we can hold vma->adjust_lock if vma_address >> returns -EFAULT. But I hope we redesigns it without new locking. >> But I don't have good idea, now. :( > > You could make it atomic through the use of RCU. > > Create a new vma entry with the changed parameters and then atomically > switch to the new vma. > Problem is that you have some list_heads in there. That's a good idea if we can do _simply_. That's because there are many confusion anon_vma and vma handling nowadays. (http://thread.gmane.org/gmane.linux.kernel/969907) So I hope we solve the problem without rather complicated rcu locking if it isn't critical path. -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>