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[209.132.180.67]) by mx.google.com with ESMTP id w2si204164otk.126.2020.01.28.16.29.54; Tue, 28 Jan 2020 16:30:09 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727170AbgA2A2y (ORCPT + 99 others); Tue, 28 Jan 2020 19:28:54 -0500 Received: from mga07.intel.com ([134.134.136.100]:18695 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727159AbgA2A2y (ORCPT ); Tue, 28 Jan 2020 19:28:54 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Jan 2020 16:28:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,375,1574150400"; d="scan'208";a="229456426" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga003.jf.intel.com with ESMTP; 28 Jan 2020 16:28:25 -0800 Date: Wed, 29 Jan 2020 08:28:38 +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: <20200129002838.GA12835@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> <20200128232907.GA11467@richard> <27b70b0c-7945-cc85-8321-d9e4b6f17865@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <27b70b0c-7945-cc85-8321-d9e4b6f17865@gmail.com> 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 Wed, Jan 29, 2020 at 02:35:25AM +0300, Dmitry Osipenko wrote: >29.01.2020 02:29, Wei Yang пишет: >> 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? > >Sure, please feel free to CC me on that patch. Thanks, you are in the cc list of v2. Hope this one works fine on ARM. -- Wei Yang Help you, Help me