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=-7.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,URIBL_DBL_ABUSE_MALW,USER_AGENT_GIT 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 38357C352A5 for ; Wed, 5 Feb 2020 12:54:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C218218AC for ; Wed, 5 Feb 2020 12:54:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=shipmail.org header.i=@shipmail.org header.b="iq0wNGkO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728298AbgBEMyn (ORCPT ); Wed, 5 Feb 2020 07:54:43 -0500 Received: from ste-pvt-msa1.bahnhof.se ([213.80.101.70]:23662 "EHLO ste-pvt-msa1.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728134AbgBEMy3 (ORCPT ); Wed, 5 Feb 2020 07:54:29 -0500 Received: from localhost (localhost [127.0.0.1]) by ste-pvt-msa1.bahnhof.se (Postfix) with ESMTP id CD4E03F695; Wed, 5 Feb 2020 13:54:27 +0100 (CET) Authentication-Results: ste-pvt-msa1.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=iq0wNGkO; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from ste-pvt-msa1.bahnhof.se ([127.0.0.1]) by localhost (ste-pvt-msa1.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IdEYKwXtpuB6; Wed, 5 Feb 2020 13:54:23 +0100 (CET) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by ste-pvt-msa1.bahnhof.se (Postfix) with ESMTPA id A930B3F669; Wed, 5 Feb 2020 13:54:18 +0100 (CET) Received: from localhost.localdomain.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id 32FC1360413; Wed, 5 Feb 2020 13:54:18 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1580907258; bh=b14LVZl/+itpO85NpGNOLmY5imFMUhPrKjnSv3EgZ4c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iq0wNGkOta0XVDOb4TsmUnEau5JJ6UnHcTcKtTptRJf9qO7ebH2AyH4imdZyDk5pA cDvaeW7pk2xtLSWFFCiGOAZgbJH4su10Ij45+oCozqPfgS7PhIUl0ndlqaQ3ywps3E kkw7Ip76PhyQnFUv/o06hpT5I45oPMNK6i5B9LcA= From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m=20=28VMware=29?= To: linux-mm@kvack.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: pv-drivers@vmware.com, linux-graphics-maintainer@vmware.com, Thomas Hellstrom , Andrew Morton , Michal Hocko , "Matthew Wilcox (Oracle)" , "Kirill A. Shutemov" , Ralph Campbell , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , =?UTF-8?q?Christian=20K=C3=B6nig?= , Dan Williams Subject: [PATCH v3 3/9] mm: Split huge pages on write-notify or COW Date: Wed, 5 Feb 2020 13:53:47 +0100 Message-Id: <20200205125353.2760-4-thomas_os@shipmail.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200205125353.2760-1-thomas_os@shipmail.org> References: <20200205125353.2760-1-thomas_os@shipmail.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Hellstrom We currently only do COW and write-notify on the PTE level, so if the huge_fault() handler returns VM_FAULT_FALLBACK on wp faults, split the huge pages and page-table entries. Also do this for huge PUDs if there is no huge_fault() handler and the vma is not anonymous, similar to how it's done for PMDs. Note that fs/dax.c does the splitting in the huge_fault() handler, but as huge_fault() is implemented by modules we need to consider whether to export the splitting functions for use in the modules or whether to try to keep calls in the core. Opt for the latter. A follow-up patch can remove the dax.c split_huge_pmd() if needed. Cc: Andrew Morton Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Kirill A. Shutemov" Cc: Ralph Campbell Cc: "Jérôme Glisse" Cc: "Christian König" Cc: Dan Williams Signed-off-by: Thomas Hellstrom --- mm/memory.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 17aadc751e5c..4c49fe963e5c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3880,11 +3880,14 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd) { if (vma_is_anonymous(vmf->vma)) return do_huge_pmd_wp_page(vmf, orig_pmd); - if (vmf->vma->vm_ops->huge_fault) - return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); + if (vmf->vma->vm_ops->huge_fault) { + vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); - /* COW handled on pte level: split pmd */ - VM_BUG_ON_VMA(vmf->vma->vm_flags & VM_SHARED, vmf->vma); + if (!(ret & VM_FAULT_FALLBACK)) + return ret; + } + + /* COW or write-notify handled on pte level: split pmd. */ __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); return VM_FAULT_FALLBACK; @@ -3897,12 +3900,20 @@ static inline bool vma_is_accessible(struct vm_area_struct *vma) static vm_fault_t create_huge_pud(struct vm_fault *vmf) { -#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ + defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) /* No support for anonymous transparent PUD pages yet */ if (vma_is_anonymous(vmf->vma)) - return VM_FAULT_FALLBACK; - if (vmf->vma->vm_ops->huge_fault) - return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); + goto split; + if (vmf->vma->vm_ops->huge_fault) { + vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD); + + if (!(ret & VM_FAULT_FALLBACK)) + return ret; + } +split: + /* COW or write-notify not handled on PUD level: split pud.*/ + __split_huge_pud(vmf->vma, vmf->pud, vmf->address); #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ return VM_FAULT_FALLBACK; } -- 2.21.1