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 35767C433EF for ; Mon, 7 Mar 2022 05:07:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234549AbiCGFIa (ORCPT ); Mon, 7 Mar 2022 00:08:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230215AbiCGFI2 (ORCPT ); Mon, 7 Mar 2022 00:08:28 -0500 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B393010E9 for ; Sun, 6 Mar 2022 21:07:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646629653; x=1678165653; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=Dp9grBEsh9qgvv8Wpxg4ToQAypx/TtvNKWPX6UIX9cc=; b=hQ/5CMXoCW4ESju1Llc3WmnpuJ83NKHnre/zPLSb67w5ZXVbBlsXxvXj L19i8ZR4eYwOIv3klLqOCY1EyVtuBufG29gM9/UShVoCSxvQSEO2CwlbP OQ0k0WIiCREzDLLeagQTiitPkH1d4s9i3PWzwcPRvuvKXFdGDkR7ctpkh IVHz3lTE+SUsWMKYEBEMnq6ctn9M9OtnvqY0YwTpgE+p70xsu7HRioMZU Za0VUCVdhmmO+MYFece2vBaQvzv4uc4VIDeujjI+b9crON8H8fRrB8yJU WOMkiT1lsBa8nMnhhsTPFmmgVktQXnttOpu3vRC/4+TQxx5PTPd1/jUoC A==; X-IronPort-AV: E=McAfee;i="6200,9189,10278"; a="251875220" X-IronPort-AV: E=Sophos;i="5.90,160,1643702400"; d="scan'208";a="251875220" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Mar 2022 21:07:33 -0800 X-IronPort-AV: E=Sophos;i="5.90,160,1643702400"; d="scan'208";a="536962197" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.239.13.94]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Mar 2022 21:07:28 -0800 From: "Huang, Ying" To: Miaohe Lin Cc: , , , , , , , , , , , , , , , , , Subject: Re: [PATCH 13/16] mm/migration: return errno when isolate_huge_page failed References: <20220304093409.25829-1-linmiaohe@huawei.com> <20220304093409.25829-14-linmiaohe@huawei.com> Date: Mon, 07 Mar 2022 13:07:26 +0800 In-Reply-To: <20220304093409.25829-14-linmiaohe@huawei.com> (Miaohe Lin's message of "Fri, 4 Mar 2022 17:34:06 +0800") Message-ID: <87ilsq5p0x.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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Miaohe Lin writes: > We should return errno (-EBUSY here) when failed to isolate the huge page > rather than always return 1 which could confuse the user. > > Signed-off-by: Miaohe Lin > --- > mm/migrate.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 6c2dfed2ddb8..279940c0c064 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1618,10 +1618,8 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, > goto out_putpage; > > if (PageHuge(page)) { > - if (PageHead(page)) { > - isolate_huge_page(page, pagelist); > - err = 1; > - } > + if (PageHead(page)) > + err = isolate_huge_page(page, pagelist) ? 1 : -EBUSY; IMHO, it's better to determine the proper errno inside isolate_huge_page() instead of in the caller. If you think it's necessary to get errno here. How about change isolate_huge_page() instead? Best Regards, Huang, Ying > } else { > struct page *head;