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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 933CAC43613 for ; Thu, 20 Jun 2019 20:54:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6AFC82084E for ; Thu, 20 Jun 2019 20:54:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="qYjAYh45" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727200AbfFTUy3 (ORCPT ); Thu, 20 Jun 2019 16:54:29 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:61600 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726943AbfFTUyM (ORCPT ); Thu, 20 Jun 2019 16:54:12 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5KKjEKX003592 for ; Thu, 20 Jun 2019 13:54:12 -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=G4U2JA+ITVRUPcGtQR0tfoOVR3mjydybAs8QYLDNQp4=; b=qYjAYh45EGSY4OgxqpFwWGg173IslKGH4D3OsTeKJXtWmuZlesb9RpVT52HsRwDBYrEL Fx12DrVOZvp8XDbzVrxGphAcObmSiRfknktbFbxwYqpBr4L6lEdV8lEXmbJJUhctBMiA LBduJdWjlB5W8F4f8yH2HvX+yPNEFv2uj9Q= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2t8eru0naj-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Thu, 20 Jun 2019 13:54:11 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::125) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Thu, 20 Jun 2019 13:54:09 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 1608262E2A35; Thu, 20 Jun 2019 13:54:09 -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 v5 6/6] mm,thp: avoid writes to file with THP in pagecache Date: Thu, 20 Jun 2019 13:53:48 -0700 Message-ID: <20190620205348.3980213-7-songliubraving@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190620205348.3980213-1-songliubraving@fb.com> References: <20190620205348.3980213-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-20_14:,, 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=615 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906200149 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Song Liu --- fs/inode.c | 3 +++ fs/namei.c | 22 +++++++++++++++++++++- include/linux/fs.h | 31 +++++++++++++++++++++++++++++++ mm/filemap.c | 1 + mm/khugepaged.c | 4 +++- 5 files changed, 59 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..3edf4ee42eee 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -444,6 +444,10 @@ 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 +2794,33 @@ 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 fbcff5a1d65a..17ebe9da56ce 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1500,8 +1500,10 @@ static void collapse_file(struct vm_area_struct *vma, 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); -- 2.17.1