From patchwork Tue Mar 3 10:22:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Thomas_Hellstr=C3=B6m_=28Intel=29?= X-Patchwork-Id: 11417651 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4ED46924 for ; Tue, 3 Mar 2020 10:23:22 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2D0612166E for ; Tue, 3 Mar 2020 10:23:22 +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 2D0612166E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shipmail.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8D3176EA0C; Tue, 3 Mar 2020 10:23:14 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from pio-pvt-msa2.bahnhof.se (pio-pvt-msa2.bahnhof.se [79.136.2.41]) by gabe.freedesktop.org (Postfix) with ESMTPS id 954946E9D2 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 X-Spam-Flag: NO X-Spam-Score: -2.099 X-Spam-Level: X-Spam-Status: No, score=-2.099 tagged_above=-999 required=6.31 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no 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_Hellstr=C3=B6m_=28VMware=29?= To: linux-mm@kvack.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org 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 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Hellstrom , Michal Hocko , pv-drivers@vmware.com, Dan Williams , Ralph Campbell , "Matthew Wilcox \(Oracle\)" , =?utf-8?b?SsOpcsO0bWUg?= =?utf-8?b?R2xpc3Nl?= , linux-graphics-maintainer@vmware.com, Andrew Morton , =?utf-8?q?Christian_K=C3=B6nig?= , "Kirill A. Shutemov" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 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 Acked-by: Christian König --- 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_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; @@ -3949,12 +3952,20 @@ 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; }