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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57C58C43334 for ; Mon, 13 Jun 2022 05:34:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C427C8D014B; Mon, 13 Jun 2022 01:34:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BCA318D0142; Mon, 13 Jun 2022 01:34:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6BB08D014B; Mon, 13 Jun 2022 01:34:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 90CC28D0142 for ; Mon, 13 Jun 2022 01:34:04 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 6524560BBF for ; 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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; 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bh=WhzHtx6D4qYDCb/PfA3aXa5De2+eI0/SundhySKGtIQ=; b=Okr8Y2m9RoE58lQFFGfv16Q4xLgHKFT2AhveYAztmKT1ronf1ClW6mO1ig6nFdomzwS36A 9Q9vDw/hoO/CF7A82HcLDfsHxNBmbTUwZ+TPAe5QcoMMVjhVbWTe3O+eYx7yOPpnV9RNsx oCXnL8Q/YQHktLGZXb2JIw++QIZUM3A= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 7CE0B1C007C X-Rspam-User: Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=X05cHB4t; spf=none (imf18.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=ying.huang@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Stat-Signature: zwfmkbqudueha4aa69pcyy4zfypsydqt X-HE-Tag: 1655098443-614839 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: 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