From 3a7200af3d9227767869f451ed747aff07d8df48 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Wed, 11 Sep 2013 14:22:19 -0700 Subject: mm: compaction: do not compact pgdat for order-0 If kswapd was reclaiming for a high order and resets it to 0 due to fragmentation it will still call compact_pgdat. For the most part, this will fail a compaction_suitable() test and not compact but it is unnecessarily sloppy. It could be fixed in the caller but fix it in the API instead. [dhillf@gmail.com: pointed out that it was a potential problem] Signed-off-by: Mel Gorman Cc: Hillf Danton Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/compaction.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'mm/compaction.c') diff --git a/mm/compaction.c b/mm/compaction.c index 05ccb4cc0bdb..c43789388cd8 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1131,6 +1131,9 @@ void compact_pgdat(pg_data_t *pgdat, int order) .sync = false, }; + if (!order) + return; + __compact_pgdat(pgdat, &cc); } -- cgit v1.2.3 From f6ea3adb70b20ae36277a1b0eaaf4da9f6479a28 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Mon, 30 Sep 2013 13:45:03 -0700 Subject: mm/compaction.c: periodically schedule when freeing pages We've been getting warnings about an excessive amount of time spent allocating pages for migration during memory compaction without scheduling. isolate_freepages_block() already periodically checks for contended locks or the need to schedule, but isolate_freepages() never does. When a zone is massively long and no suitable targets can be found, this iteration can be quite expensive without ever doing cond_resched(). Check periodically for the need to reschedule while the compaction free scanner iterates. Signed-off-by: David Rientjes Reviewed-by: Rik van Riel Reviewed-by: Wanpeng Li Acked-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/compaction.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'mm/compaction.c') diff --git a/mm/compaction.c b/mm/compaction.c index c43789388cd8..b5326b141a25 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -677,6 +677,13 @@ static void isolate_freepages(struct zone *zone, pfn -= pageblock_nr_pages) { unsigned long isolated; + /* + * This can iterate a massively long zone without finding any + * suitable migration targets, so periodically check if we need + * to schedule. + */ + cond_resched(); + if (!pfn_valid(pfn)) continue; -- cgit v1.2.3