On 03/20/2012 01:07 PM, Peter Zijlstra wrote: > On Tue, 2012-03-20 at 12:52 +0200, Avi Kivity wrote: > > > You use the dma engine for eager copying, not on demand. > > Sure, but during that time no access to that entire vma is allowed, so > you have to unmap it, and any fault in there will have to wait for the > entire copy to complete. > > Or am I misunderstanding how things would work? Option 1: write-protect the area you are migrating, on write fault allow write access and discard the migration target (marking the page for migration later) Option 2: clear the dirty bits on the area you are migrating, after migration completes examine the dirty bit, and if dirty, discard the migration target. -- error compiling committee.c: too many arguments to function -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>