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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1A3AC433EF for ; Fri, 15 Oct 2021 01:42:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 99F9960F23 for ; Fri, 15 Oct 2021 01:42:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 99F9960F23 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 31AD86B006C; Thu, 14 Oct 2021 21:42:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2CA6E900002; Thu, 14 Oct 2021 21:42:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1B8C46B0072; Thu, 14 Oct 2021 21:42:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0172.hostedemail.com [216.40.44.172]) by kanga.kvack.org (Postfix) with ESMTP id 0874B6B006C for ; Thu, 14 Oct 2021 21:42:26 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B0063184509B9 for ; Fri, 15 Oct 2021 01:42:25 +0000 (UTC) X-FDA: 78696971850.25.3449E1C Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf10.hostedemail.com (Postfix) with ESMTP id 502496001983 for ; Fri, 15 Oct 2021 01:42:23 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10137"; a="214992293" X-IronPort-AV: E=Sophos;i="5.85,374,1624345200"; d="scan'208";a="214992293" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Oct 2021 18:42:23 -0700 X-IronPort-AV: E=Sophos;i="5.85,374,1624345200"; d="scan'208";a="592827275" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.239.159.119]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Oct 2021 18:42:21 -0700 From: "Huang, Ying" To: Yang Shi Cc: dave.hansen@linux.intel.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: migrate: make demotion knob depend on migration References: <20211015005559.246709-1-shy828301@gmail.com> Date: Fri, 15 Oct 2021 09:42:19 +0800 In-Reply-To: <20211015005559.246709-1-shy828301@gmail.com> (Yang Shi's message of "Thu, 14 Oct 2021 17:55:59 -0700") Message-ID: <875ytznjwk.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Queue-Id: 502496001983 X-Stat-Signature: ds94cu7dwto735shxddb6r35fi1fd4yf Authentication-Results: imf10.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none); spf=none (imf10.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.20) smtp.mailfrom=ying.huang@intel.com X-Rspamd-Server: rspam02 X-HE-Tag: 1634262143-418598 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Yang Shi writes: > The memory demotion needs to call migrate_pages() to do the jobs. And > it is controlled by a knob, however, the knob doesn't depend on > CONFIG_MIGRATION. The knob could be truned on even though MIGRATION is > disabled, this will not cause any crash since migrate_pages() would just > return -ENOSYS. But it is definitely not optimal to go through demotion > path then retry regular swap every time. > > And it doesn't make too much sense to have the knob visible to the users > when !MIGRATION. Move the related code from mempolicy.[h|c] to migrate.[h|c]. Sounds reasonable to me. Thanks! > Signed-off-by: Yang Shi Acked-by: "Huang, Ying" Best Regards, Huang, Ying