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=-9.5 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,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 1F2EAC432C0 for ; Wed, 27 Nov 2019 08:32:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAAC12070B for ; Wed, 27 Nov 2019 08:32:25 +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="SKBX2VHS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727060AbfK0IcY (ORCPT ); Wed, 27 Nov 2019 03:32:24 -0500 Received: from pio-pvt-msa3.bahnhof.se ([79.136.2.42]:35826 "EHLO pio-pvt-msa3.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726204AbfK0IcQ (ORCPT ); Wed, 27 Nov 2019 03:32:16 -0500 Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa3.bahnhof.se (Postfix) with ESMTP id 9F72E3F5BF; Wed, 27 Nov 2019 09:32:13 +0100 (CET) Authentication-Results: pio-pvt-msa3.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=SKBX2VHS; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from pio-pvt-msa3.bahnhof.se ([127.0.0.1]) by localhost (pio-pvt-msa3.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id jM6coC0IXBPB; Wed, 27 Nov 2019 09:32:05 +0100 (CET) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by pio-pvt-msa3.bahnhof.se (Postfix) with ESMTPA id 05D393F5AE; Wed, 27 Nov 2019 09:32:02 +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 7A01436037D; Wed, 27 Nov 2019 09:32:02 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1574843522; bh=+m8VIGOM4hHWg9ASpsN1nrWT205H44kgXg6hbjLA1Dg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SKBX2VHSrStFphgDRYDXqRsbsGdOIfqGWoRiYui+VMFnvTvXmpAh+vz7TJRZN+hGW 6XxxDWgvlbh7xrttMcQGXBQ0w87B81VcHrEDko6KFZb/nKJmQTCbuzEwTgbMgkY9E6 1KRuqQ/x0lMBB4iCoQtlT9XyfcjMi0auNwN9k0yI= From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m=20=28VMware=29?= To: dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-graphics-maintainer@vmware.com Cc: 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?= Subject: [RFC PATCH 2/7] mm: Split huge pages on write-notify or COW Date: Wed, 27 Nov 2019 09:31:15 +0100 Message-Id: <20191127083120.34611-3-thomas_os@shipmail.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191127083120.34611-1-thomas_os@shipmail.org> References: <20191127083120.34611-1-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" Signed-off-by: Thomas Hellstrom --- mm/memory.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 28f162e28144..89b8a7730d66 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3755,11 +3755,14 @@ 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; @@ -3787,9 +3790,16 @@ static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud) #ifdef CONFIG_TRANSPARENT_HUGEPAGE /* 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; } -- 2.21.0