From patchwork Sun Jun 23 05:47:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 11011573 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 106361908 for ; Sun, 23 Jun 2019 05:48:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0085828B2A for ; Sun, 23 Jun 2019 05:48:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E85D128B2C; Sun, 23 Jun 2019 05:48:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5664928B2B for ; Sun, 23 Jun 2019 05:48:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726477AbfFWFsM (ORCPT ); Sun, 23 Jun 2019 01:48:12 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:31324 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726467AbfFWFsL (ORCPT ); Sun, 23 Jun 2019 01:48:11 -0400 Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5N5iEvG015402 for ; Sat, 22 Jun 2019 22:48:10 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=OCLrqfSXcpxK+1VOccrQtP7qai4h6E5adUP8VenR0FM=; b=XACg37lKEV90/F5mriDHnYNQrSoMA73T2pJ1EfyNCjj0mnKpdojTvsQUJLFebiS8eshZ RughF7uKEfJhTDjYho2hW+eZsIX3xaKPxsqfd9J8PD2o5HOezvj3GNp5qN+u5p8BACKl 2vlKjgnvmueW56iXHP5M5NCxaQRQX1oRPFA= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2t9fmjjfmm-6 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sat, 22 Jun 2019 22:48:10 -0700 Received: from mx-out.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::d) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Sat, 22 Jun 2019 22:48:07 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 2EA2C62E2CFB; Sat, 22 Jun 2019 22:48:06 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig006.ftw2.facebook.com To: , , CC: , , , , , , Song Liu Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v7 6/6] mm,thp: avoid writes to file with THP in pagecache Date: Sat, 22 Jun 2019 22:47:49 -0700 Message-ID: <20190623054749.4016638-7-songliubraving@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190623054749.4016638-1-songliubraving@fb.com> References: <20190623054749.4016638-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-23_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=768 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906230050 X-FB-Internal: deliver Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In previous patch, an application could put part of its text section in THP via madvise(). These THPs will be protected from writes when the application is still running (TXTBSY). However, after the application exits, the file is available for writes. This patch avoids writes to file THP by dropping page cache for the file when the file is open for write. A new counter nr_thps is added to struct address_space. In do_last(), if the file is open for write and nr_thps is non-zero, we drop page cache for the whole file. Reported-by: kbuild test robot Signed-off-by: Song Liu --- fs/inode.c | 3 +++ fs/namei.c | 22 +++++++++++++++++++++- include/linux/fs.h | 32 ++++++++++++++++++++++++++++++++ mm/filemap.c | 1 + mm/khugepaged.c | 4 +++- 5 files changed, 60 insertions(+), 2 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index df6542ec3b88..518113a4e219 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -181,6 +181,9 @@ int inode_init_always(struct super_block *sb, struct inode *inode) mapping->flags = 0; mapping->wb_err = 0; atomic_set(&mapping->i_mmap_writable, 0); +#ifdef CONFIG_READ_ONLY_THP_FOR_FS + atomic_set(&mapping->nr_thps, 0); +#endif mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); mapping->private_data = NULL; mapping->writeback_index = 0; diff --git a/fs/namei.c b/fs/namei.c index 20831c2fbb34..de64f24b58e9 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3249,6 +3249,22 @@ static int lookup_open(struct nameidata *nd, struct path *path, return error; } +/* + * The file is open for write, so it is not mmapped with VM_DENYWRITE. If + * it still has THP in page cache, drop the whole file from pagecache + * before processing writes. This helps us avoid handling write back of + * THP for now. + */ +static inline void release_file_thp(struct file *file) +{ +#ifdef CONFIG_READ_ONLY_THP_FOR_FS + struct inode *inode = file_inode(file); + + if (inode_is_open_for_write(inode) && filemap_nr_thps(inode->i_mapping)) + truncate_pagecache(inode, 0); +#endif +} + /* * Handle the last step of open() */ @@ -3418,7 +3434,11 @@ static int do_last(struct nameidata *nd, goto out; opened: error = ima_file_check(file, op->acc_mode); - if (!error && will_truncate) + if (error) + goto out; + + release_file_thp(file); + if (will_truncate) error = handle_truncate(file); out: if (unlikely(error > 0)) { diff --git a/include/linux/fs.h b/include/linux/fs.h index f7fdfe93e25d..082fc581c7fc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -427,6 +427,7 @@ int pagecache_write_end(struct file *, struct address_space *mapping, * @i_pages: Cached pages. * @gfp_mask: Memory allocation flags to use for allocating pages. * @i_mmap_writable: Number of VM_SHARED mappings. + * @nr_thps: Number of THPs in the pagecache (non-shmem only). * @i_mmap: Tree of private and shared mappings. * @i_mmap_rwsem: Protects @i_mmap and @i_mmap_writable. * @nrpages: Number of page entries, protected by the i_pages lock. @@ -444,6 +445,10 @@ struct address_space { struct xarray i_pages; gfp_t gfp_mask; atomic_t i_mmap_writable; +#ifdef CONFIG_READ_ONLY_THP_FOR_FS + /* number of thp, only for non-shmem files */ + atomic_t nr_thps; +#endif struct rb_root_cached i_mmap; struct rw_semaphore i_mmap_rwsem; unsigned long nrpages; @@ -2790,6 +2795,33 @@ static inline errseq_t filemap_sample_wb_err(struct address_space *mapping) return errseq_sample(&mapping->wb_err); } +static inline int filemap_nr_thps(struct address_space *mapping) +{ +#ifdef CONFIG_READ_ONLY_THP_FOR_FS + return atomic_read(&mapping->nr_thps); +#else + return 0; +#endif +} + +static inline void filemap_nr_thps_inc(struct address_space *mapping) +{ +#ifdef CONFIG_READ_ONLY_THP_FOR_FS + atomic_inc(&mapping->nr_thps); +#else + WARN_ON_ONCE(1); +#endif +} + +static inline void filemap_nr_thps_dec(struct address_space *mapping) +{ +#ifdef CONFIG_READ_ONLY_THP_FOR_FS + atomic_dec(&mapping->nr_thps); +#else + WARN_ON_ONCE(1); +#endif +} + extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync); extern int vfs_fsync(struct file *file, int datasync); diff --git a/mm/filemap.c b/mm/filemap.c index e79ceccdc6df..a8e86c136381 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -205,6 +205,7 @@ static void unaccount_page_cache_page(struct address_space *mapping, __dec_node_page_state(page, NR_SHMEM_THPS); } else if (PageTransHuge(page)) { __dec_node_page_state(page, NR_FILE_THPS); + filemap_nr_thps_dec(mapping); } /* diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 090127e4e185..a4f90a1b06f5 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1499,8 +1499,10 @@ static void collapse_file(struct mm_struct *mm, if (is_shmem) __inc_node_page_state(new_page, NR_SHMEM_THPS); - else + else { __inc_node_page_state(new_page, NR_FILE_THPS); + filemap_nr_thps_inc(mapping); + } if (nr_none) { struct zone *zone = page_zone(new_page);