On Fri, 2011-04-15 at 14:20 -0500, Anthony Liguori wrote: > On 04/15/2011 02:15 PM, Dave Hansen wrote: > > On Fri, 2011-04-15 at 12:17 -0500, Anthony Liguori wrote: > >> If you're in OOM and you need memory, you can't ask the host for more > >> and wait for a response. You have to reclaim it immediately. > > Why not? The call in to the notifier chain the s390 case is > > synchronous. The OOM only affects one task at a time and won't proceed > > elsewhere while this is going on. > > Because if we tell the host, we have to wait for the host to ack which > means we'd sleep waiting for an interrupt. Can you do this in the OOM path?
Sure. One of the s390 handlers sleeps today. > > Why do we even _tell_ qemu, though? The MADV_WILLNEED is nice, but far > > from being necessary. We could just skip the entire notification in OOM > > situations. > > There's really no particular reason to other than symmetry. When we get there, it sounds like we can simply _skip_ the notification in the qemu case. -- Dave
