From 78dc583d3ab43115579cb5f3f7bd12e3548dd5a5 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Tue, 16 Jun 2009 15:31:40 -0700 Subject: [PATCH] vmscan: low order lumpy reclaim also should use PAGEOUT_IO_SYNC Commit 33c120ed2843090e2bd316de1588b8bf8b96cbde ("more aggressively use lumpy reclaim") increased how aggressive lumpy reclaim was by isolating both active and inactive pages for asynchronous lumpy reclaim on costly-high-order pages and for cheap-high-order when memory pressure is high. However, if the system is under heavy pressure and there are dirty pages, asynchronous IO may not be sufficient to reclaim a suitable page in time. This patch causes the caller to enter synchronous lumpy reclaim for costly-high-order pages and for cheap-high-order pages when under memory pressure. Minchan.kim@gmail.com said: Andy added synchronous lumpy reclaim with c661b078fd62abe06fd11fab4ac5e4eeafe26b6d. At that time, lumpy reclaim is not agressive. His intension is just for high-order users.(above PAGE_ALLOC_COSTLY_ORDER). After some time, Rik added aggressive lumpy reclaim with 33c120ed2843090e2bd316de1588b8bf8b96cbde. His intention was to do lumpy reclaim when high-order users and trouble getting a small set of contiguous pages. So we also have to add synchronous pageout for small set of contiguous pages. Cc: Lee Schermerhorn Cc: Andy Whitcroft Acked-by: Peter Zijlstra Cc: Rik van Riel Signed-off-by: KOSAKI Motohiro Reviewed-by: Minchan Kim Reviewed-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-format-patch failed