On 05/22/2014 05:09 AM, Mel Gorman wrote: > Commit "mm: vmscan: obey proportional scanning requirements for kswapd" > ensured that file/anon lists were scanned proportionally for reclaim from > kswapd but ignored it for direct reclaim. The intent was to minimse direct > reclaim latency but Yuanhan Liu pointer out that it substitutes one long > stall for many small stalls and distorts aging for normal workloads like > streaming readers/writers. Hugh Dickins pointed out that a side-effect of > the same commit was that when one LRU list dropped to zero that the entirety > of the other list was shrunk leading to excessive reclaim in memcgs. > This patch scans the file/anon lists proportionally for direct reclaim > to similarly age page whether reclaimed by kswapd or direct reclaim but > takes care to abort reclaim if one LRU drops to zero after reclaiming the > requested number of pages. > > Note that there are fewer allocation stalls even though the amount > of direct reclaim scanning is very approximately the same. > > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Acked-by: Rik van Riel <riel@xxxxxxxxxx> -- All rights reversed -- 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>