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,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 5B794C4360C for ; Thu, 10 Oct 2019 13:41:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3510721A4A for ; Thu, 10 Oct 2019 13:41:25 +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="X+y/07DC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388268AbfJJNlY (ORCPT ); Thu, 10 Oct 2019 09:41:24 -0400 Received: from pio-pvt-msa1.bahnhof.se ([79.136.2.40]:44104 "EHLO pio-pvt-msa1.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733228AbfJJNlV (ORCPT ); Thu, 10 Oct 2019 09:41:21 -0400 Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa1.bahnhof.se (Postfix) with ESMTP id 590523F598; Thu, 10 Oct 2019 15:41:19 +0200 (CEST) Authentication-Results: pio-pvt-msa1.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b="X+y/07DC"; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from pio-pvt-msa1.bahnhof.se ([127.0.0.1]) by localhost (pio-pvt-msa1.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Wl0QoKF-zCWb; Thu, 10 Oct 2019 15:41:18 +0200 (CEST) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by pio-pvt-msa1.bahnhof.se (Postfix) with ESMTPA id E9AE93F58C; Thu, 10 Oct 2019 15:41:17 +0200 (CEST) Received: from localhost.localdomain.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id 7D18E36016C; Thu, 10 Oct 2019 15:41:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1570714877; bh=PbaGuh2AWzgR/QobTlpM3PYlJJowJXX6P7DMUtKFhwc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X+y/07DCYti5qO8GpDRx7v6qmNnd1qY4d+px/dYzGwT/xp4RIn7PYIWspQ0IqSV5k T4E+F8ZdO3cy4VxhktQQac/74KLcQaOPnohGoQXODFsAYS7v5WSu25HzRX1Bxm9r4R qTMpmKo7XQMCwVieRVRZ2yPsEEPBimGYbC3+eQ7M= From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m=20=28VMware=29?= To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, kirill@shutemov.name Cc: Thomas Hellstrom Subject: [RFC PATCH 4/4] mm: mapping_dirty_helpers: Handle huge pmds correctly Date: Thu, 10 Oct 2019 15:40:58 +0200 Message-Id: <20191010134058.11949-5-thomas_os@shipmail.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191010134058.11949-1-thomas_os@shipmail.org> References: <20191010134058.11949-1-thomas_os@shipmail.org> MIME-Version: 1.0 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 always do dirty tracking on the PTE level. This means that any huge pmds we encounter should be read-only and not dirty: We can just skip those. Write-enabled huge pmds should not exist. They should have been split when made write-enabled. Warn and attempt to split them. Signed-off-by: Thomas Hellstrom --- mm/mapping_dirty_helpers.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c index 799b9154b48f..f61bb9de1530 100644 --- a/mm/mapping_dirty_helpers.c +++ b/mm/mapping_dirty_helpers.c @@ -115,11 +115,18 @@ static int clean_record_pte(pte_t *pte, unsigned long addr, static int wp_clean_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long end, struct mm_walk *walk) { - /* Dirty-tracking should be handled on the pte level */ pmd_t pmdval = pmd_read_atomic(pmd); - if (pmd_trans_huge(pmdval) || pmd_devmap(pmdval)) - WARN_ON(pmd_write(pmdval) || pmd_dirty(pmdval)); + /* + * Dirty-tracking should be handled on the pte level, and write- + * enabled huge PMDS should never have been created. Warn on those. + * Read-only huge PMDS can't be dirty so we just skip them. + */ + if (pmd_trans_huge(pmdval) || pmd_devmap(pmdval)) { + if (WARN_ON(pmd_write(pmdval) || pmd_dirty(pmdval))) + return 0; + return PAGE_WALK_CONTINUE; + } return 0; } -- 2.21.0