From patchwork Sun Apr 24 09:11:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12824827 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79E3AC433EF for ; Sun, 24 Apr 2022 09:10:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9F6376B007B; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9CDA86B0078; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 894676B007E; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 757C16B0078 for ; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 56FFE22805 for ; Sun, 24 Apr 2022 09:10:46 +0000 (UTC) X-FDA: 79391202492.13.2ECD9F0 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf27.hostedemail.com (Postfix) with ESMTP id 6F2D040035 for ; Sun, 24 Apr 2022 09:10:44 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4KmMmJ41hYz1JBMN; Sun, 24 Apr 2022 17:09:52 +0800 (CST) Received: from huawei.com (10.175.124.27) 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; Sun, 24 Apr 2022 17:10:41 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , Subject: [PATCH v3 2/3] mm/swapfile: Fix lost swap bits in unuse_pte() Date: Sun, 24 Apr 2022 17:11:04 +0800 Message-ID: <20220424091105.48374-3-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220424091105.48374-1-linmiaohe@huawei.com> References: <20220424091105.48374-1-linmiaohe@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Stat-Signature: x7ggbz4xppfiqmxose9gpzj8qst1zfw8 Authentication-Results: imf27.hostedemail.com; dkim=none; spf=pass (imf27.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 6F2D040035 X-HE-Tag: 1650791444-481710 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This is observed by code review only but not any real report. When we turn off swapping we could have lost the bits stored in the swap ptes. The new rmap-exclusive bit is fine since that turned into a page flag, but not for soft-dirty and uffd-wp. Add them. Suggested-by: Peter Xu Signed-off-by: Miaohe Lin Reviewed-by: David Hildenbrand --- mm/swapfile.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 95b63f69f388..522a0eb16bf1 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1783,7 +1783,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, { struct page *swapcache; spinlock_t *ptl; - pte_t *pte; + pte_t *pte, new_pte; int ret = 1; swapcache = page; @@ -1832,8 +1832,12 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, page_add_new_anon_rmap(page, vma, addr); lru_cache_add_inactive_or_unevictable(page, vma); } - set_pte_at(vma->vm_mm, addr, pte, - pte_mkold(mk_pte(page, vma->vm_page_prot))); + new_pte = pte_mkold(mk_pte(page, vma->vm_page_prot)); + if (pte_swp_soft_dirty(*pte)) + new_pte = pte_mksoft_dirty(new_pte); + if (pte_swp_uffd_wp(*pte)) + new_pte = pte_mkuffd_wp(new_pte); + set_pte_at(vma->vm_mm, addr, pte, new_pte); swap_free(entry); out: pte_unmap_unlock(pte, ptl);