On 05/07/2014 04:22 AM, David Rientjes wrote:
Async compaction terminates prematurely when need_resched(), see
compact_checklock_irqsave(). This can never trigger, however, if the
cond_resched() in isolate_migratepages_range() always takes care of the
scheduling.
If the cond_resched() actually triggers, then terminate this pageblock scan for
async compaction as well.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
---
mm/compaction.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/mm/compaction.c b/mm/compaction.c
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -500,8 +500,13 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
return 0;
}
+ if (cond_resched()) {
+ /* Async terminates prematurely on need_resched() */
+ if (cc->mode == MIGRATE_ASYNC)
+ return 0;
+ }
+
/* Time to isolate some pages for migration */
- cond_resched();
for (; low_pfn < end_pfn; low_pfn++) {
/* give a chance to irqs before checking need_resched() */
if (locked && !(low_pfn % SWAP_CLUSTER_MAX)) {
--
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