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=-9.6 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,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 F3278C3F2DB for ; Tue, 3 Mar 2020 10:23:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AF67C214D8 for ; Tue, 3 Mar 2020 10:23:19 +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="XzKbFy1v" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF67C214D8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shipmail.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6482D6B000C; Tue, 3 Mar 2020 05:23:14 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5A9FE6B0010; Tue, 3 Mar 2020 05:23:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 29E546B000D; Tue, 3 Mar 2020 05:23:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0201.hostedemail.com [216.40.44.201]) by kanga.kvack.org (Postfix) with ESMTP id F3E3F6B000A for ; Tue, 3 Mar 2020 05:23:13 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 8FD763CE1 for ; Tue, 3 Mar 2020 10:23:13 +0000 (UTC) X-FDA: 76553663466.15.back95_9064ee344b301 X-HE-Tag: back95_9064ee344b301 X-Filterd-Recvd-Size: 6172 Received: from pio-pvt-msa2.bahnhof.se (pio-pvt-msa2.bahnhof.se [79.136.2.41]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Tue, 3 Mar 2020 10:23:12 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTP id CFADC3F5C5; Tue, 3 Mar 2020 11:23:10 +0100 (CET) Authentication-Results: pio-pvt-msa2.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=XzKbFy1v; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from pio-pvt-msa2.bahnhof.se ([127.0.0.1]) by localhost (pio-pvt-msa2.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id s18uY9_YmiAV; Tue, 3 Mar 2020 11:23:05 +0100 (CET) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id 8DAF43F374; Tue, 3 Mar 2020 11:22:59 +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 377CB3605FD; Tue, 3 Mar 2020 11:22:59 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1583230979; bh=eArF6ZjbQdomBzBVnzbUQcGFkrLPEvAM1NjLa5asgsg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XzKbFy1vvDq9Qqj/53vwQWoztOK+QmPXWJqVpcNmqIf7XzEIEQEFM/jzuzNqstJEg V6/wdQSNdnKti8SV6jBWZeN4bkwc8q5VIbaM4dHxFRTMuu0ebI2VsZ91/qOqn2Uvtr aMpFPrIMnqKPMWJNRbYK8MruGzHSKyNB3iVcF2RA= 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 v5 3/9] mm: Split huge pages on write-notify or COW Date: Tue, 3 Mar 2020 11:22:41 +0100 Message-Id: <20200303102247.4635-4-thomas_os@shipmail.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200303102247.4635-1-thomas_os@shipmail.org> References: <20200303102247.4635-1-thomas_os@shipmail.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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: From: Thomas Hellstrom The functions wp_huge_pmd() and wp_huge_pud() currently relies on the huge_fault() callback to split huge page table entries if needed. However for module users that requires export of the split_huge_xxx() functionality which may be undesired. Instead split pre-existing huge page-table entries on VM_FAULT_FALLBACK return. 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 still does the splitting in the huge_fault() handler, = but as huge_fault() A follow-up patch can remove the dax.c split_huge_pmd() if n= eeded. Cc: Andrew Morton Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Kirill A. Shutemov" Cc: Ralph Campbell Cc: "J=C3=A9r=C3=B4me Glisse" Cc: "Christian K=C3=B6nig" Cc: Dan Williams Signed-off-by: Thomas Hellstrom Acked-by: Christian K=C3=B6nig --- mm/memory.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 0bccc622e482..1e3fc1988790 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3932,11 +3932,14 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fa= ult *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 =3D vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD); =20 - /* 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); =20 return VM_FAULT_FALLBACK; @@ -3949,12 +3952,20 @@ static inline bool vma_is_accessible(struct vm_ar= ea_struct *vma) =20 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 =3D 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; } --=20 2.21.1