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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 DC857C76191 for ; Mon, 22 Jul 2019 03:22:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 776FA21921 for ; Mon, 22 Jul 2019 03:22:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="DSd3O0zQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 776FA21921 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E09286B0003; Sun, 21 Jul 2019 23:22:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D933A6B0006; Sun, 21 Jul 2019 23:22:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C31F88E0001; Sun, 21 Jul 2019 23:22:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ua1-f72.google.com (mail-ua1-f72.google.com [209.85.222.72]) by kanga.kvack.org (Postfix) with ESMTP id 9B09C6B0003 for ; Sun, 21 Jul 2019 23:22:58 -0400 (EDT) Received: by mail-ua1-f72.google.com with SMTP id d1so3560974uak.23 for ; Sun, 21 Jul 2019 20:22:58 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:subject:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=bKQhUIwcPyqKlsiS6x+9R5sqKFbs4BHgdjnU5G7EHlc=; b=kYfzH43DYWaOLy2G/N8zHYXniPd6WTV3NBJr3WRZXIsGocnR6r+5TOmEXXxjvRHeaD 3faLY5UdaVq6jNwMB1BOfOpaT63oAruFTrrCfuIVu044DwWwkpw/ecCyV8iQu8WX5ABu rdhSiYz2y90I6JFL57E0VTEyaqvQlTucfN/lEotjcuf0z54Mu5A0aaakg6lleaskyE8p WfMsrMlTZ0TwawdNZQuMYM+r+gas4nPHOm/wKyP+nOZo+vVWfx89IbebJwIU9eA3a19G wkhqclwBUWdKsy5+RTIrata12zYLdV5rbwtRATxqKg/zqlf199DX4T1soL+alDRKaUoz OtRw== X-Gm-Message-State: APjAAAUm6mHls6+p8fXeGW2lxFi4tMDrs+LdafKlhwmBNsC9qwsdCPIZ +U55pDmc+KNU/IMDVxto6oNvgtbqCDI8T3+aCZRR+jIQIxJlPjtVu3wFvowyn31Wg4wWINHAj25 6/nMPzhf8/49ApdtmwzAkfE92VBSAHP9nrqKpIjiygwncHNRc/MC7ZPGDKP6fRr7lkg== X-Received: by 2002:a67:ad07:: with SMTP id t7mr40982569vsl.214.1563765778220; Sun, 21 Jul 2019 20:22:58 -0700 (PDT) X-Google-Smtp-Source: APXvYqyO9onQbAzq279RW61ywlogb10FQ9x3AIMZuVN3/bqDSjkuze5AYKvgZeip08urFDQ7Y23A X-Received: by 2002:a67:ad07:: with SMTP id t7mr40982547vsl.214.1563765777396; Sun, 21 Jul 2019 20:22:57 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1563765777; cv=none; d=google.com; s=arc-20160816; b=Je2GJphsfqBe8JXoxH77vtXup+lmb+PAUQYuBBQyjfXw8FY+JG7bGKYUqrIsKXnM71 EwPOwh+7YZ78UiFeiTebQzg70sICU9SNUP2z3PKeyBSYovb2QmSBEaOqolXSjwyMVKa9 Xa2fzegPxKs3+FI2onsFvvqemGJ61QXp17dK1hfboXSg1qdtAO/5tyQmdtHz7265dRZo QgiEEFuIS1cM6THsrMihmdpirVijQcSl56bS7tMNQnQMXE2skrYu4nGsEMNighrXNvv/ tkHVFWdLvGoHfU62ZfMNcQ/1DDy11iBls1z0Rsp1UI/U1yhNdzv/7rMEleJmZ/fu7p/0 PSEw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:dkim-signature; bh=bKQhUIwcPyqKlsiS6x+9R5sqKFbs4BHgdjnU5G7EHlc=; b=GG0/YomnhC5xGbnRnppX+Pg04BZWX7GjzuBxjzPKohEO2JGR2UJtUWGuluxx9VOKB2 6LvOGPxuLEuiIXn0ja5VUNqyEWddDLsrQIWOCWham91aRgJ3192ub99UlfNCthhws0bi eIl3ycJ3O8yCoz0CTlLuDK0QMeh43XpO+YnGaCrgwYffpKXGFhhONT2vZ3wsZ5g4R3lq KDIuBMxeqrOyhZu1mfSXLaNnT59MmYojbs6rEIWWzxDG22JPUsTvflKlxijtcaGJ9WDb 0DL4dpEJvnwRXIZkjRHASDqPH4hJX91d7sOB0rFuohMxMRPYpAQFT5TRhLg55GHlwX9k WohA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=DSd3O0zQ; spf=pass (google.com: domain of william.kucharski@oracle.com designates 156.151.31.85 as permitted sender) smtp.mailfrom=william.kucharski@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from userp2120.oracle.com (userp2120.oracle.com. [156.151.31.85]) by mx.google.com with ESMTPS id q4si9181837vsd.280.2019.07.21.20.22.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 21 Jul 2019 20:22:57 -0700 (PDT) Received-SPF: pass (google.com: domain of william.kucharski@oracle.com designates 156.151.31.85 as permitted sender) client-ip=156.151.31.85; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=DSd3O0zQ; spf=pass (google.com: domain of william.kucharski@oracle.com designates 156.151.31.85 as permitted sender) smtp.mailfrom=william.kucharski@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6M3J2WK091282; Mon, 22 Jul 2019 03:22:48 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2018-07-02; bh=bKQhUIwcPyqKlsiS6x+9R5sqKFbs4BHgdjnU5G7EHlc=; b=DSd3O0zQ4FRuEjIau9hjPInOC22IFeXHKkPNWBaycJAbDHtCgMnpC0R1qzzazWNn2RUp EJzbnMEVutxkhqtjKo1/+F7bc7ijlOUIzsjGpFuoKM8xPSBE+8KBvKfL6COUGBASbIlR NdLk9dXDx8Uen+1SYPrcWtbJqaHAVmhKu/mftrglskgSnxq5VwlqTejE4ywdch5Z1ze0 oArggfQEIHPkpkIJv/Fc/TQAjoa9W4LqjYoP3FIT/KA2VJsi50HmO/BadAEYf2tYhq6J A7dQ1qX9Mtp9egiAdbo7amW9Ap4/oWGzGcus5DRjghh4qJZRMF+MX0wvshHrZMwhEg9C gA== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 2tuukqbw6h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 22 Jul 2019 03:22:47 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6M3I18c139244; Mon, 22 Jul 2019 03:20:46 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3020.oracle.com with ESMTP id 2tuts2g8uc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 22 Jul 2019 03:20:46 +0000 Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x6M3KdXA015002; Mon, 22 Jul 2019 03:20:39 GMT Received: from [192.168.0.110] (/73.243.10.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 21 Jul 2019 20:20:38 -0700 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3566.0.1\)) Subject: Re: [PATCH 2/3] sgi-gru: Remove CONFIG_HUGETLB_PAGE ifdef From: William Kucharski In-Reply-To: <1563724685-6540-3-git-send-email-linux.bhar@gmail.com> Date: Sun, 21 Jul 2019 21:20:38 -0600 Cc: arnd@arndb.de, sivanich@sgi.com, gregkh@linuxfoundation.org, ira.weiny@intel.com, jhubbard@nvidia.com, jglisse@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Transfer-Encoding: quoted-printable Message-Id: <1BA84A99-4EB5-4520-BFBD-CD60D5B7AED9@oracle.com> References: <1563724685-6540-1-git-send-email-linux.bhar@gmail.com> <1563724685-6540-3-git-send-email-linux.bhar@gmail.com> To: Bharath Vedartham X-Mailer: Apple Mail (2.3566.0.1) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9325 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907220037 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9325 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907220037 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: I suspect I'm being massively pedantic here, but the comments for = atomic_pte_lookup() note: * Only supports Intel large pages (2MB only) on x86_64. * ZZZ - hugepage support is incomplete That makes me wonder how many systems using this hardware are actually = configured with CONFIG_HUGETLB_PAGE. I ask as in the most common case, this is likely introducing a few extra = instructions and possibly an additional branch to a routine that is = called per-fault. So the nit-picky questions are: 1) Does the code really need to be cleaned up in this way? 2) If it does, does it make more sense (given the way pmd_large() is = handled now in atomic_pte_lookup()) for this to be coded as: if (unlikely(is_vm_hugetlb_page(vma))) *pageshift =3D HPAGE_SHIFT; else *pageshift =3D PAGE_SHIFT; In all likelihood, these questions are no-ops, and the optimizer may = even make my questions completely moot, but I thought I might as well = ask anyway. > On Jul 21, 2019, at 9:58 AM, Bharath Vedartham = wrote: >=20 > is_vm_hugetlb_page has checks for whether CONFIG_HUGETLB_PAGE is = defined > or not. If CONFIG_HUGETLB_PAGE is not defined is_vm_hugetlb_page will > always return false. There is no need to have an uneccessary > CONFIG_HUGETLB_PAGE check in the code. >=20 > Cc: Ira Weiny > Cc: John Hubbard > Cc: J=C3=A9r=C3=B4me Glisse > Cc: Greg Kroah-Hartman > Cc: Dimitri Sivanich > Cc: Arnd Bergmann > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org > Signed-off-by: Bharath Vedartham > --- > drivers/misc/sgi-gru/grufault.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) >=20 > diff --git a/drivers/misc/sgi-gru/grufault.c = b/drivers/misc/sgi-gru/grufault.c > index 61b3447..75108d2 100644 > --- a/drivers/misc/sgi-gru/grufault.c > +++ b/drivers/misc/sgi-gru/grufault.c > @@ -180,11 +180,8 @@ static int non_atomic_pte_lookup(struct = vm_area_struct *vma, > { > struct page *page; >=20 > -#ifdef CONFIG_HUGETLB_PAGE > *pageshift =3D is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : = PAGE_SHIFT; > -#else > - *pageshift =3D PAGE_SHIFT; > -#endif > + > if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, = NULL) <=3D 0) > return -EFAULT; > *paddr =3D page_to_phys(page); > @@ -238,11 +235,9 @@ static int atomic_pte_lookup(struct = vm_area_struct *vma, unsigned long vaddr, > return 1; >=20 > *paddr =3D pte_pfn(pte) << PAGE_SHIFT; > -#ifdef CONFIG_HUGETLB_PAGE > + > *pageshift =3D is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : = PAGE_SHIFT; > -#else > - *pageshift =3D PAGE_SHIFT; > -#endif > + > return 0; >=20 > err: > --=20 > 2.7.4 >=20