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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 7B021C19759 for ; Thu, 1 Aug 2019 08:05:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D9B2214DA for ; Thu, 1 Aug 2019 08:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730561AbfHAIFI (ORCPT ); Thu, 1 Aug 2019 04:05:08 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:40504 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725790AbfHAIFH (ORCPT ); Thu, 1 Aug 2019 04:05:07 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 7E83CA1EA9312ABEAB26; Thu, 1 Aug 2019 16:04:42 +0800 (CST) Received: from [10.134.22.195] (10.134.22.195) by smtp.huawei.com (10.3.19.207) with Microsoft SMTP Server (TLS) id 14.3.439.0; Thu, 1 Aug 2019 16:04:39 +0800 Subject: Re: [f2fs-dev] [PATCH] f2fs: fix livelock in swapfile writes To: Jaegeuk Kim CC: , References: <20190731204353.62056-1-jaegeuk@kernel.org> <20190801042650.GD84433@jaegeuk-macbookpro.roam.corp.google.com> From: Chao Yu Message-ID: Date: Thu, 1 Aug 2019 16:04:38 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190801042650.GD84433@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/8/1 12:26, Jaegeuk Kim wrote: > On 08/01, Chao Yu wrote: >> On 2019/8/1 4:43, Jaegeuk Kim wrote: >>> This patch fixes livelock in the below call path when writing swap pages. >>> >>> [46374.617256] c2 701 __switch_to+0xe4/0x100 >>> [46374.617265] c2 701 __schedule+0x80c/0xbc4 >>> [46374.617273] c2 701 schedule+0x74/0x98 >>> [46374.617281] c2 701 rwsem_down_read_failed+0x190/0x234 >>> [46374.617291] c2 701 down_read+0x58/0x5c >>> [46374.617300] c2 701 f2fs_map_blocks+0x138/0x9a8 >>> [46374.617310] c2 701 get_data_block_dio_write+0x74/0x104 >>> [46374.617320] c2 701 __blockdev_direct_IO+0x1350/0x3930 >>> [46374.617331] c2 701 f2fs_direct_IO+0x55c/0x8bc >>> [46374.617341] c2 701 __swap_writepage+0x1d0/0x3e8 >>> [46374.617351] c2 701 swap_writepage+0x44/0x54 >>> [46374.617360] c2 701 shrink_page_list+0x140/0xe80 >>> [46374.617371] c2 701 shrink_inactive_list+0x510/0x918 >>> [46374.617381] c2 701 shrink_node_memcg+0x2d4/0x804 >>> [46374.617391] c2 701 shrink_node+0x10c/0x2f8 >>> [46374.617400] c2 701 do_try_to_free_pages+0x178/0x38c >>> [46374.617410] c2 701 try_to_free_pages+0x348/0x4b8 >>> [46374.617419] c2 701 __alloc_pages_nodemask+0x7f8/0x1014 >>> [46374.617429] c2 701 pagecache_get_page+0x184/0x2cc >>> [46374.617438] c2 701 f2fs_new_node_page+0x60/0x41c >>> [46374.617449] c2 701 f2fs_new_inode_page+0x50/0x7c >>> [46374.617460] c2 701 f2fs_init_inode_metadata+0x128/0x530 >>> [46374.617472] c2 701 f2fs_add_inline_entry+0x138/0xd64 >>> [46374.617480] c2 701 f2fs_do_add_link+0xf4/0x178 >>> [46374.617488] c2 701 f2fs_create+0x1e4/0x3ac >>> [46374.617497] c2 701 path_openat+0xdc0/0x1308 >>> [46374.617507] c2 701 do_filp_open+0x78/0x124 >>> [46374.617516] c2 701 do_sys_open+0x134/0x248 >>> [46374.617525] c2 701 SyS_openat+0x14/0x20 >>> >>> Signed-off-by: Jaegeuk Kim >>> --- >>> fs/f2fs/data.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index abbf14e9bd72..f49f243fd54f 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -1372,7 +1372,7 @@ static int get_data_block_dio_write(struct inode *inode, sector_t iblock, >>> return __get_data_block(inode, iblock, bh_result, create, >>> F2FS_GET_BLOCK_DIO, NULL, >>> f2fs_rw_hint_to_seg_type(inode->i_write_hint), >>> - true); >>> + IS_SWAPFILE(inode) ? false : true); >> >> I suspect that we should use node_change for swapfile rather than just changing >> may_write field to skip lock. > > Swap write should not change the node page. You're right. Reviewed-by: Chao Yu Thanks, > >> >> __do_map_lock() >> if (flag == F2FS_GET_BLOCK_PRE_AIO || IS_SWAPFILE(inode)) { >> ... >> } else { >> ... >> } >> >> Thanks, >> >> >>> } >>> >>> static int get_data_block_dio(struct inode *inode, sector_t iblock, >>> > . >