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 for low order allocation - kswapd: always delegate io to flusher thread - direct reclaim: delegate io to flusher thread only if vm pressure is low This seems more safely. I mean Who want see incorrect oom regression? I've made some pathes for this. I'll post it as another mail. > Then we can work towards allowing lumpy reclaim to use background > threads as Chris suggested for doing specific writeback operations > to solve the remaining problems being seen. Does this seem like a > reasonable compromise and approach to dealing with the problem? Tend to agree. probably now we are discussing right approach. but this is definitely needed deep thinking. then, I can't take exactly answer yet. -- 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>