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=-13.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 CF85DC2D0DB for ; Tue, 28 Jan 2020 23:28:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB9FC207FD for ; Tue, 28 Jan 2020 23:28:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726422AbgA1X25 (ORCPT ); Tue, 28 Jan 2020 18:28:57 -0500 Received: from mga14.intel.com ([192.55.52.115]:47301 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726293AbgA1X25 (ORCPT ); Tue, 28 Jan 2020 18:28:57 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Jan 2020 15:28:57 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,375,1574150400"; d="scan'208";a="261613284" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga002.fm.intel.com with ESMTP; 28 Jan 2020 15:28:54 -0800 Date: Wed, 29 Jan 2020 07:29:07 +0800 From: Wei Yang To: Dmitry Osipenko Cc: Wei Yang , Russell King - ARM Linux , akpm@linux-foundation.org, dan.j.williams@intel.com, aneesh.kumar@linux.ibm.com, kirill@shutemov.name, yang.shi@linux.alibaba.com, thellstrom@vmware.com, Thierry Reding , Jon Hunter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "linux-tegra@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 3/5] mm/mremap: use pmd_addr_end to calculate next in move_page_tables() Message-ID: <20200128232907.GA11467@richard> Reply-To: Wei Yang References: <20200117232254.2792-1-richardw.yang@linux.intel.com> <20200117232254.2792-4-richardw.yang@linux.intel.com> <7147774a-14e9-4ff3-1548-4565f0d214d5@gmail.com> <20200128004301.GD20624@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 28, 2020 at 06:59:48PM +0300, Dmitry Osipenko wrote: >28.01.2020 03:43, Wei Yang пишет: >> On Sun, Jan 26, 2020 at 05:47:57PM +0300, Dmitry Osipenko wrote: >>> 18.01.2020 02:22, Wei Yang пишет: >>>> Use the general helper instead of do it by hand. >>>> >>>> Signed-off-by: Wei Yang >>>> --- >>>> mm/mremap.c | 7 ++----- >>>> 1 file changed, 2 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/mm/mremap.c b/mm/mremap.c >>>> index c2af8ba4ba43..a258914f3ee1 100644 >>>> --- a/mm/mremap.c >>>> +++ b/mm/mremap.c >>>> @@ -253,11 +253,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma, >>>> >>>> for (; old_addr < old_end; old_addr += extent, new_addr += extent) { >>>> cond_resched(); >>>> - next = (old_addr + PMD_SIZE) & PMD_MASK; >>>> - /* even if next overflowed, extent below will be ok */ >>>> + next = pmd_addr_end(old_addr, old_end); >>>> extent = next - old_addr; >>>> - if (extent > old_end - old_addr) >>>> - extent = old_end - old_addr; >>>> old_pmd = get_old_pmd(vma->vm_mm, old_addr); >>>> if (!old_pmd) >>>> continue; >>>> @@ -301,7 +298,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma, >>>> >>>> if (pte_alloc(new_vma->vm_mm, new_pmd)) >>>> break; >>>> - next = (new_addr + PMD_SIZE) & PMD_MASK; >>>> + next = pmd_addr_end(new_addr, new_addr + len); >>>> if (extent > next - new_addr) >>>> extent = next - new_addr; >>>> move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma, >>>> >>> >>> Hello Wei, >>> >>> Starting with next-20200122, I'm seeing the following in KMSG on NVIDIA >>> Tegra (ARM32): >>> >>> BUG: Bad rss-counter state mm:(ptrval) type:MM_ANONPAGES val:190 >>> >> >> Thanks. >> >> Would you mind letting me know which case you are testing? > >Nothing special, systemd starts to fall apart during boot. > >> Or the special thing is 32-bit platform? >I have a limited knowledge about mm/, so can't provide detailed explanation. > >Please take a look at this: > >[1] >https://elixir.bootlin.com/linux/v5.5/source/arch/arm/include/asm/pgtable-2level.h#L210 > >[2] >https://elixir.bootlin.com/linux/v5.5/source/include/asm-generic/pgtable.h#L549 > >[3] >https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c0ba10b512eb2e2a3888b6e6cc0e089f5e7a191b Thanks, I see the difference here. If this is the case, we can't use pmd_addr_end() to simplify the calculation. This changes the behavior. I would prepare another patch set to fix this. Would you mind helping me verify on your platform? -- Wei Yang Help you, Help me