On Tue 19-03-13 11:08:23, Simon Jeons wrote: > Hi Mel, > On 03/17/2013 09:04 PM, Mel Gorman wrote: > >kswapd stops raising the scanning priority when at least SWAP_CLUSTER_MAX > >pages have been reclaimed or the pgdat is considered balanced. It then > >rechecks if it needs to restart at DEF_PRIORITY and whether high-order > >reclaim needs to be reset. This is not wrong per-se but it is confusing > > per-se is short for what? > > >to follow and forcing kswapd to stay at DEF_PRIORITY may require several > >restarts before it has scanned enough pages to meet the high watermark even > >at 100% efficiency. This patch irons out the logic a bit by controlling > >when priority is raised and removing the "goto loop_again". > > > >This patch has kswapd raise the scanning priority until it is scanningmm: vmscan: Flatten kswapd priority loop > >enough pages that it could meet the high watermark in one shrink of the > >LRU lists if it is able to reclaim at 100% efficiency. It will not raise > > Which kind of reclaim can be treated as 100% efficiency? nr_scanned == nr_reclaimed > >the scanning prioirty higher unless it is failing to reclaim any pages. > > > >To avoid infinite looping for high-order allocation requests kswapd will > >not reclaim for high-order allocations when it has reclaimed at least > >twice the number of pages as the allocation request. > > > >Signed-off-by: Mel Gorman <mgorman@xxxxxxx> [...] -- Michal Hocko SUSE Labs -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>