On 03/25/2013 10:07 AM, Michal Hocko wrote: > On Sun 17-03-13 13:04:07, Mel Gorman wrote: >> The number of pages kswapd can reclaim is bound by the number of pages it >> scans which is related to the size of the zone and the scanning priority. In >> many cases the priority remains low because it's reset every SWAP_CLUSTER_MAX >> reclaimed pages but in the event kswapd scans a large number of pages it >> cannot reclaim, it will raise the priority and potentially discard a large >> percentage of the zone as sc->nr_to_reclaim is ULONG_MAX. The user-visible >> effect is a reclaim "spike" where a large percentage of memory is suddenly >> freed. It would be bad enough if this was just unused memory but because >> of how anon/file pages are balanced it is possible that applications get >> pushed to swap unnecessarily. >> >> This patch limits the number of pages kswapd will reclaim to the high >> watermark. Reclaim will will overshoot due to it not being a hard limit as >> shrink_lruvec() will ignore the sc.nr_to_reclaim at DEF_PRIORITY but it >> prevents kswapd reclaiming the world at higher priorities. The number of >> pages it reclaims is not adjusted for high-order allocations as kswapd will >> reclaim excessively if it is to balance zones for high-order allocations. >> >> Signed-off-by: Mel Gorman <mgorman@xxxxxxx> > > It seems I forgot to add > Reviewed-by: Michal Hocko <mhocko@xxxxxxx> Thanks, now I applied all ten. BTW I very pray this will fix also the issue I have when I run ltp tests (highly I/O intensive, esp. `growfiles') in a VM while playing a movie on the host resulting in a stuttered playback ;). -- js 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>