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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62E23C43334 for ; Mon, 13 Jun 2022 05:34:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232290AbiFMFeS (ORCPT ); Mon, 13 Jun 2022 01:34:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232622AbiFMFeI (ORCPT ); Mon, 13 Jun 2022 01:34:08 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3D4512AB3 for ; Sun, 12 Jun 2022 22:34:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655098440; x=1686634440; h=message-id:subject:from:to:cc:date:in-reply-to: references:mime-version:content-transfer-encoding; bh=/TIkaE5l1WeJcJM5zEjR0mrwq7QJSRWRIniuYy9P52s=; b=McLVqxosXxhglfCEojSyO3hO+i9u2XGWz52CNH9AM+ya8vS3vvWxRa9i aKGUTPiTDBjVQlWw1XJI3iI4Cl/Y9C6lRq0VStXuC1Ag79PyRgcB6krUy Q/cdninbKrMok11nEzkPlWNgze/IXBEexNn+zMQhQqRemv3pdBpd7qPyv 5AgU5MynHtWgBOxOkl1AGPJOerTa4yc/sooTYNxklAy6wan940sLsYxZA 5prbaZl4khg29dUomnbViXiZQqajAXTIupKbrEeAYqg4GHT7LJ0PZKgCs DtFsOz5orus+BlQFaQcsIzOM47Zp4Pu6s2CXpt15MgKrJevRPNhKPXfZy g==; X-IronPort-AV: E=McAfee;i="6400,9594,10376"; a="258609584" X-IronPort-AV: E=Sophos;i="5.91,296,1647327600"; d="scan'208";a="258609584" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jun 2022 22:34:00 -0700 X-IronPort-AV: E=Sophos;i="5.91,296,1647327600"; d="scan'208";a="587598034" Received: from xinyangc-mobl.ccr.corp.intel.com ([10.254.214.65]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jun 2022 22:33:55 -0700 Message-ID: <33b42a802a07721c639db99ed208ed43f743bb37.camel@intel.com> Subject: Re: [PATCH v6 03/13] mm/demotion: Return error on write to numa_demotion sysfs From: Ying Huang To: Aneesh Kumar K V , linux-mm@kvack.org, akpm@linux-foundation.org Cc: Wei Xu , Greg Thelen , Yang Shi , Davidlohr Bueso , Tim C Chen , Brice Goglin , Michal Hocko , Linux Kernel Mailing List , Hesham Almatary , Dave Hansen , Jonathan Cameron , Alistair Popple , Dan Williams , Feng Tang , Jagdish Gediya , Baolin Wang , David Rientjes Date: Mon, 13 Jun 2022 13:33:52 +0800 In-Reply-To: <9da3c6ef-ba0d-6229-2188-0956222b04f1@linux.ibm.com> References: <20220610135229.182859-1-aneesh.kumar@linux.ibm.com> <20220610135229.182859-4-aneesh.kumar@linux.ibm.com> <7ed1f9f544937b5c82ab380a4977e5ae22a98c43.camel@intel.com> <9da3c6ef-ba0d-6229-2188-0956222b04f1@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2022-06-13 at 09:05 +0530, Aneesh Kumar K V wrote: > On 6/13/22 8:56 AM, Ying Huang wrote: > > On Fri, 2022-06-10 at 19:22 +0530, Aneesh Kumar K.V wrote: > > > With CONFIG_MIGRATION disabled return EINVAL on write. > > > > > > Signed-off-by: Aneesh Kumar K.V > > > --- > > >   mm/memory-tiers.c | 3 +++ > > >   1 file changed, 3 insertions(+) > > > > > > diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > > > index 9c6b40d7e0bf..c3123a457d90 100644 > > > --- a/mm/memory-tiers.c > > > +++ b/mm/memory-tiers.c > > > @@ -105,6 +105,9 @@ static ssize_t numa_demotion_enabled_store(struct kobject *kobj, > > >   { > > >    ssize_t ret; > > >    > > > > > > > > > + if (!IS_ENABLED(CONFIG_MIGRATION)) > > > + return -EINVAL; > > > + > > > > How about enclose numa_demotion_enabled_xxx related code with CONFIG_MIGRATION? > > > > IIUC there is a desire to use IS_ENABLED() in the kernel instead of > #ifdef since that helps in more compile time checks. Because there are > no dead codes during compile now with IS_ENABLED(). IS_ENABLED() is used to reduce usage of "#ifdef" in ".c" file, especially inside a function. We have good build test coverage with 0Day now. To avoid code size inflate, it's better to use #ifdef CONFIG_MIGRATION. > W.r.t leaving the sysfs file visible even when CONFIG_MIGRATION is > disabled, I was thinking it gives better visibility into numa_demotion > status. I could switch to hide numa_demotion file if that is desirable. > > > >    ret = kstrtobool(buf, &numa_demotion_enabled); > > >    if (ret) > > >    return ret; > > Best Regards, Huang, Ying