On Thu, Apr 15, 2010 at 01:09:01PM +0900, KOSAKI Motohiro wrote: > Hi > > > How about this? For now, we stop direct reclaim from doing writeback > > only on order zero allocations, but allow it for higher order > > allocations. That will prevent the majority of situations where > > direct reclaim blows the stack and interferes with background > > writeout, but won't cause lumpy reclaim to change behaviour. > > This reduces the scope of impact and hence testing and validation > > the needs to be done. > > Tend to agree. but I would proposed slightly different algorithm for > avoind incorrect oom. > > for high order allocation > allow to use lumpy reclaim and pageout() for both kswapd and direct reclaim SO same as current. > for low order allocation > - kswapd: always delegate io to flusher thread > - direct reclaim: delegate io to flusher thread only if vm pressure is low IMO, this really doesn't fix either of the problems - the bad IO patterns nor the stack usage. All it will take is a bit more memory pressure to trigger stack and IO problems, and the user reporting the problems is generating an awful lot of memory pressure... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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>