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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 A05D7C47404 for ; Tue, 8 Oct 2019 00:57:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 62F2A206BB for ; Tue, 8 Oct 2019 00:57:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 62F2A206BB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0CBF68E0006; Mon, 7 Oct 2019 20:57:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 07C0B8E0003; Mon, 7 Oct 2019 20:57:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EFA588E0006; Mon, 7 Oct 2019 20:57:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0025.hostedemail.com [216.40.44.25]) by kanga.kvack.org (Postfix) with ESMTP id C938A8E0003 for ; Mon, 7 Oct 2019 20:57:46 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 5C0F64821 for ; Tue, 8 Oct 2019 00:57:46 +0000 (UTC) X-FDA: 76018804932.21.coil21_26ae7a96cd763 X-HE-Tag: coil21_26ae7a96cd763 X-Filterd-Recvd-Size: 4085 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Tue, 8 Oct 2019 00:57:45 +0000 (UTC) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Oct 2019 17:57:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,269,1566889200"; d="scan'208";a="393198372" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga005.fm.intel.com with ESMTP; 07 Oct 2019 17:57:42 -0700 Date: Tue, 8 Oct 2019 08:57:25 +0800 From: Wei Yang To: Mike Kravetz Cc: Wei Yang , Andrew Morton , aarcange@redhat.com, hughd@google.com, linux-mm@kvack.org Subject: Re: [PATCH v2 1/3] userfaultfd: use vma_pagesize for all huge page size calculation Message-ID: <20191008005725.GA13077@richard> Reply-To: Wei Yang References: <20190927070032.2129-1-richardw.yang@linux.intel.com> <20190927151033.aad57472652a0b3a6948df6e@linux-foundation.org> <20190929004507.GA11770@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) 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, Oct 07, 2019 at 03:55:21PM -0700, Mike Kravetz wrote: >On 9/28/19 5:45 PM, Wei Yang wrote: >> On Fri, Sep 27, 2019 at 03:10:33PM -0700, Andrew Morton wrote: >>> On Fri, 27 Sep 2019 15:00:30 +0800 Wei Yang wrote: >>> >>>> In function __mcopy_atomic_hugetlb, we use two variables to deal with >>>> huge page size: vma_hpagesize and huge_page_size. >>>> >>>> Since they are the same, it is not necessary to use two different >>>> mechanism. This patch makes it consistent by all using vma_hpagesize. >>>> >>>> --- a/mm/userfaultfd.c >>>> +++ b/mm/userfaultfd.c >>>> @@ -262,7 +262,7 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, >>>> pte_t dst_pteval; >>>> >>>> BUG_ON(dst_addr >= dst_start + len); >>>> - VM_BUG_ON(dst_addr & ~huge_page_mask(h)); >>>> + VM_BUG_ON(dst_addr & (vma_hpagesize - 1)); >>>> >>>> /* >>>> * Serialize via hugetlb_fault_mutex >>>> @@ -273,7 +273,7 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, >>>> mutex_lock(&hugetlb_fault_mutex_table[hash]); >>>> >>>> err = -ENOMEM; >>>> - dst_pte = huge_pte_alloc(dst_mm, dst_addr, huge_page_size(h)); >>>> + dst_pte = huge_pte_alloc(dst_mm, dst_addr, vma_hpagesize); >>>> if (!dst_pte) { >>>> mutex_unlock(&hugetlb_fault_mutex_table[hash]); >>>> goto out_unlock; >>>> @@ -300,7 +300,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, >>>> >>>> err = copy_huge_page_from_user(page, >>>> (const void __user *)src_addr, >>>> - pages_per_huge_page(h), true); >>>> + vma_hpagesize / PAGE_SIZE, >>>> + true); >>>> if (unlikely(err)) { >>>> err = -EFAULT; >>>> goto out; >>> >>> Looks right. >>> >>> We could go ahead and remove local variable `h', given that >>> hugetlb_fault_mutex_hash() doesn't actually use its first arg.. >> >> Oops, haven't imagine h is not used in the function. >> >> >> Any historical reason to pass h in hugetlb_fault_mutex_hash()? Neither these >> two definition use it. > >See 1b426bac66e6 ("hugetlb: use same fault hash key for shared and private >mappings"). Prior to that change, the hash key for private mappings was >created by: > > key[0] = (unsigned long) mm; > key[1] = address >> huge_page_shift(h); > >When removing that code, I should have removed 'h'. Thanks for this information. >-- >Mike Kravetz -- Wei Yang Help you, Help me