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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 EB38FC10F00 for ; Thu, 21 Mar 2019 21:15:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5B8D21925 for ; Thu, 21 Mar 2019 21:15:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727235AbfCUVPZ (ORCPT ); Thu, 21 Mar 2019 17:15:25 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:59440 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726589AbfCUVPY (ORCPT ); Thu, 21 Mar 2019 17:15:24 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x2LLE90v002066 for ; Thu, 21 Mar 2019 17:15:23 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2rchhya3vw-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 21 Mar 2019 17:15:23 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 21 Mar 2019 21:15:19 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (9.149.109.194) by e06smtp07.uk.ibm.com (192.168.101.137) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 21 Mar 2019 21:15:14 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x2LLFEwk15663334 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Mar 2019 21:15:14 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6EC2052050; Thu, 21 Mar 2019 21:15:14 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.206.163]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTPS id A164852054; Thu, 21 Mar 2019 21:15:12 +0000 (GMT) Date: Thu, 21 Mar 2019 23:15:10 +0200 From: Mike Rapoport To: Steven Price Cc: linux-mm@kvack.org, Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Dave Hansen , Ingo Molnar , James Morse , =?iso-8859-1?B?Suly9G1l?= Glisse , Peter Zijlstra , Thomas Gleixner , Will Deacon , x86@kernel.org, "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mark Rutland , "Liang, Kan" Subject: Re: [PATCH v5 10/19] mm: pagewalk: Add p4d_entry() and pgd_entry() References: <20190321141953.31960-1-steven.price@arm.com> <20190321141953.31960-11-steven.price@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190321141953.31960-11-steven.price@arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19032121-0028-0000-0000-00000356D2E0 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19032121-0029-0000-0000-000024157AD0 Message-Id: <20190321211510.GA27213@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-03-21_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 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-1903210149 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 21, 2019 at 02:19:44PM +0000, Steven Price wrote: > pgd_entry() and pud_entry() were removed by commit 0b1fbfe50006c410 > ("mm/pagewalk: remove pgd_entry() and pud_entry()") because there were > no users. We're about to add users so reintroduce them, along with > p4d_entry() as we now have 5 levels of tables. > > Note that commit a00cc7d9dd93d66a ("mm, x86: add support for > PUD-sized transparent hugepages") already re-added pud_entry() but with > different semantics to the other callbacks. Since there have never > been upstream users of this, revert the semantics back to match the > other callbacks. This means pud_entry() is called for all entries, not > just transparent huge pages. > > Signed-off-by: Steven Price > --- > include/linux/mm.h | 9 ++++++--- > mm/pagewalk.c | 27 ++++++++++++++++----------- > 2 files changed, 22 insertions(+), 14 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 76769749b5a5..2983f2396a72 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1367,10 +1367,9 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma, > > /** > * mm_walk - callbacks for walk_page_range > + * @pgd_entry: if set, called for each non-empty PGD (top-level) entry > + * @p4d_entry: if set, called for each non-empty P4D (1st-level) entry IMHO, p4d implies the 4th level :) I think it would make more sense to start counting from PTE rather than from PGD. Then it would be consistent across architectures with fewer levels. > * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry > - * this handler should only handle pud_trans_huge() puds. > - * the pmd_entry or pte_entry callbacks will be used for > - * regular PUDs. > * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry > * this handler is required to be able to handle > * pmd_trans_huge() pmds. They may simply choose to > @@ -1390,6 +1389,10 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma, > * (see the comment on walk_page_range() for more details) > */ > struct mm_walk { > + int (*pgd_entry)(pgd_t *pgd, unsigned long addr, > + unsigned long next, struct mm_walk *walk); > + int (*p4d_entry)(p4d_t *p4d, unsigned long addr, > + unsigned long next, struct mm_walk *walk); > int (*pud_entry)(pud_t *pud, unsigned long addr, > unsigned long next, struct mm_walk *walk); > int (*pmd_entry)(pmd_t *pmd, unsigned long addr, > diff --git a/mm/pagewalk.c b/mm/pagewalk.c > index c3084ff2569d..98373a9f88b8 100644 > --- a/mm/pagewalk.c > +++ b/mm/pagewalk.c > @@ -90,15 +90,9 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, > } > > if (walk->pud_entry) { > - spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma); > - > - if (ptl) { > - err = walk->pud_entry(pud, addr, next, walk); > - spin_unlock(ptl); > - if (err) > - break; > - continue; > - } > + err = walk->pud_entry(pud, addr, next, walk); > + if (err) > + break; > } > > split_huge_pud(walk->vma, pud, addr); > @@ -131,7 +125,12 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, > break; > continue; > } > - if (walk->pmd_entry || walk->pte_entry) > + if (walk->p4d_entry) { > + err = walk->p4d_entry(p4d, addr, next, walk); > + if (err) > + break; > + } > + if (walk->pud_entry || walk->pmd_entry || walk->pte_entry) > err = walk_pud_range(p4d, addr, next, walk); > if (err) > break; > @@ -157,7 +156,13 @@ static int walk_pgd_range(unsigned long addr, unsigned long end, > break; > continue; > } > - if (walk->pmd_entry || walk->pte_entry) > + if (walk->pgd_entry) { > + err = walk->pgd_entry(pgd, addr, next, walk); > + if (err) > + break; > + } > + if (walk->p4d_entry || walk->pud_entry || walk->pmd_entry || > + walk->pte_entry) > err = walk_p4d_range(pgd, addr, next, walk); > if (err) > break; > -- > 2.20.1 > -- Sincerely yours, Mike.