From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27097C10F0E for ; Thu, 18 Apr 2019 04:16:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED53F2083D for ; Thu, 18 Apr 2019 04:16:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726339AbfDREQI (ORCPT ); Thu, 18 Apr 2019 00:16:08 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:35622 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725710AbfDREQI (ORCPT ); Thu, 18 Apr 2019 00:16:08 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R711e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0TPc2a8C_1555560943; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TPc2a8C_1555560943) by smtp.aliyun-inc.com(127.0.0.1); Thu, 18 Apr 2019 12:15:58 +0800 To: Mel Gorman , Michal Hocko , Andrea Arcangeli , "Kirill A. Shutemov" Cc: YangShi , "linux-mm@kvack.org" , linux-kernel From: Yang Shi Subject: [QUESTIONS] THP allocation in NUMA fault migration path Message-ID: Date: Wed, 17 Apr 2019 21:15:41 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi folks, I noticed that there might be new THP allocation in NUMA fault migration path (migrate_misplaced_transhuge_page()) even when THP is disabled (set to "never"). When THP is set to "never", there should be not any new THP allocation, but the migration path is kind of special. So I'm not quite sure if this is the expected behavior or not? And, it looks this allocation disregards defrag setting too, is this expected behavior too? Thanks, Yang