Messages in this thread Patch in this message | | | From | js1304@gmail ... | Subject | [PATCH] mm/thp: don't count ZONE_MOVABLE as the target for freepage reserving | Date | Thu, 5 Apr 2018 16:27:16 +0900 |
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From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
ZONE_MOVABLE only has movable pages so we don't need to keep enough freepages to avoid or deal with fragmentation. So, don't count it.
This changes min_free_kbytes and thus min_watermark greatly if ZONE_MOVABLE is used. It will make the user uses more memory.
o System 22GB ram, fakenuma, 2 nodes. 5 zones are used.
o Before min_free_kbytes: 112640
zone_info (min_watermark): Node 0, zone DMA min 19 Node 0, zone DMA32 min 3778 Node 0, zone Normal min 10191 Node 0, zone Movable min 0 Node 0, zone Device min 0 Node 1, zone DMA min 0 Node 1, zone DMA32 min 0 Node 1, zone Normal min 14043 Node 1, zone Movable min 127 Node 1, zone Device min 0
o After min_free_kbytes: 90112
zone_info (min_watermark): Node 0, zone DMA min 15 Node 0, zone DMA32 min 3022 Node 0, zone Normal min 8152 Node 0, zone Movable min 0 Node 0, zone Device min 0 Node 1, zone DMA min 0 Node 1, zone DMA32 min 0 Node 1, zone Normal min 11234 Node 1, zone Movable min 102 Node 1, zone Device min 0
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> --- mm/khugepaged.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 5de1c6f..92dd4e6 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1880,8 +1880,16 @@ static void set_recommended_min_free_kbytes(void) int nr_zones = 0; unsigned long recommended_min; - for_each_populated_zone(zone) + for_each_populated_zone(zone) { + /* + * We don't need to worry about fragmentation of + * ZONE_MOVABLE since it only has movable pages. + */ + if (zone_idx(zone) > gfp_zone(GFP_USER)) + continue; + nr_zones++; + } /* Ensure 2 pageblocks are free to assist fragmentation avoidance */ recommended_min = pageblock_nr_pages * nr_zones * 2; -- 2.7.4
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