[PATCH] [RFC] mm/compaction: initialize compaction information

[Gioh Kim <gioh.kim@lge.com>]

I tried to start compaction via /proc/sys/vm/compact_memory
as soon as I turned on my ARM-based platform.
But the compaction didn't start.
I found some variables in struct zone are not initalized.

I think zone->compact_cached_free_pfn and some cache values for compaction
are initalized when the kernel starts compaction, not via
/proc/sys/vm/compact_memory.
If my guess is correct, an initialization are needed for that case.


Signed-off-by: Gioh Kim <gioh.kim@lge.com>
---
 mm/compaction.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/mm/compaction.c b/mm/compaction.c
index 8c0d945..944a9cc 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1299,6 +1299,14 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 		__reset_isolation_suitable(zone);
 
 	/*
+	 * If this is activated by /proc/sys/vm/compact_memory
+	 * and the first try, cached information for compaction is not
+	 * initialized.
+	 */
+	if (cc->order == -1 && zone->compact_cached_free_pfn == 0)
+		__reset_isolation_suitable(zone);
+
+	/*
 	 * Setup to move all movable pages to the end of the zone. Used cached
 	 * information on where the scanners should start but check that it
 	 * is initialised by ensuring the values are within zone boundaries.
-- 
1.7.9.5

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