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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB515C433F5 for ; Mon, 25 Apr 2022 02:00:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240304AbiDYCDD (ORCPT ); Sun, 24 Apr 2022 22:03:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240276AbiDYCCn (ORCPT ); Sun, 24 Apr 2022 22:02:43 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1A8C5DE67 for ; Sun, 24 Apr 2022 18:59:40 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Kmp6R2ShVzGpFF; Mon, 25 Apr 2022 09:57:03 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 25 Apr 2022 09:59:37 +0800 Subject: Re: [PATCH v3 3/3] mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range To: =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= CC: "akpm@linux-foundation.org" , "willy@infradead.org" , "vbabka@suse.cz" , "dhowells@redhat.com" , "neilb@suse.de" , "david@redhat.com" , "apopple@nvidia.com" , "surenb@google.com" , "minchan@kernel.org" , "peterx@redhat.com" , "sfr@canb.auug.org.au" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" References: <20220424091105.48374-1-linmiaohe@huawei.com> <20220424091105.48374-4-linmiaohe@huawei.com> <20220424234128.GA3740950@hori.linux.bs1.fc.nec.co.jp> From: Miaohe Lin Message-ID: <66a3d738-9dcb-76d6-6507-abbb13569709@huawei.com> Date: Mon, 25 Apr 2022 09:59:36 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20220424234128.GA3740950@hori.linux.bs1.fc.nec.co.jp> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/4/25 7:41, HORIGUCHI NAOYA(堀口 直也) wrote: > On Sun, Apr 24, 2022 at 05:11:05PM +0800, Miaohe Lin wrote: >> Once the MADV_FREE operation has succeeded, callers can expect they might >> get zero-fill pages if accessing the memory again. Therefore it should be >> safe to delete the hwpoison entry and swapin error entry. There is no >> reason to kill the process if it has called MADV_FREE on the range. >> >> Suggested-by: Alistair Popple >> Signed-off-by: Miaohe Lin >> Acked-by: David Hildenbrand > > I confirmed that hwpoison entry is properly removed with madvise(MADV_FREE) > with this patch. This provides applications with the ability to recover from > memory errors in simpler way (applications don't have to munmap then mmap again > the error address). That's a good small improvement. Thank you. > > Reviewed-by: Naoya Horiguchi Many thanks for your testing and review! :) > >> --- >> mm/madvise.c | 13 ++++++++----- >> 1 file changed, 8 insertions(+), 5 deletions(-) >> >> diff --git a/mm/madvise.c b/mm/madvise.c >> index 4d6592488b51..5f4537511532 100644 >> --- a/mm/madvise.c >> +++ b/mm/madvise.c >> @@ -624,11 +624,14 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, >> swp_entry_t entry; >> >> entry = pte_to_swp_entry(ptent); >> - if (non_swap_entry(entry)) >> - continue; >> - nr_swap--; >> - free_swap_and_cache(entry); >> - pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); >> + if (!non_swap_entry(entry)) { >> + nr_swap--; >> + free_swap_and_cache(entry); >> + pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); >> + } else if (is_hwpoison_entry(entry) || >> + is_swapin_error_entry(entry)) { >> + pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); >> + } >> continue; >> } >> >> -- >> 2.23.0