From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f72.google.com (mail-pl0-f72.google.com [209.85.160.72]) by kanga.kvack.org (Postfix) with ESMTP id DEA3B6B0003 for ; Thu, 5 Apr 2018 03:27:29 -0400 (EDT) Received: by mail-pl0-f72.google.com with SMTP id o33-v6so15763875plb.16 for ; Thu, 05 Apr 2018 00:27:29 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id y72-v6sor2913700plh.63.2018.04.05.00.27.28 for (Google Transport Security); Thu, 05 Apr 2018 00:27:28 -0700 (PDT) From: js1304@gmail.com Subject: [PATCH] mm/thp: don't count ZONE_MOVABLE as the target for freepage reserving Date: Thu, 5 Apr 2018 16:27:16 +0900 Message-Id: <1522913236-15776-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Kirill A . Shutemov" , Michal Hocko , Mel Gorman , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim From: Joonsoo Kim 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 --- 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