On Mon, Jun 03, 2013 at 01:02:10PM -0700, Dave Hansen wrote: > > From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > > This was a suggestion from Mel: > > http://lkml.kernel.org/r/20120914085634.GM11157@xxxxxxxxx > > Any pages we collect on 'batch_for_mapping_removal' will have > their lock_page() held during the duration of their stay on the > list. If some other user is trying to get at them during this > time, they might end up having to wait. > > This ensures that we drain the batch if we are about to perform a > pageout() or congestion_wait(), either of which will take some > time. We expect this to help mitigate the worst of the latency > increase that the batching could cause. > > I added some statistics to the __remove_mapping_batch() code to > track how large the lists are that we pass in to it. With this > patch, the average list length drops about 10% (from about 4.1 to > 3.8). The workload here was a make -j4 kernel compile on a VM > with 200MB of RAM. > > I've still got the statistics patch around if anyone is > interested. > > Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Reviewed-by: Minchan Kim <minchan@xxxxxxxxxx> -- Kind regards, Minchan Kim -- 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>