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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 6A18FC04EB9 for ; Tue, 16 Oct 2018 01:31:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 290E02089E for ; Tue, 16 Oct 2018 01:31:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 290E02089E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727013AbeJPJTZ (ORCPT ); Tue, 16 Oct 2018 05:19:25 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:13656 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726946AbeJPJTY (ORCPT ); Tue, 16 Oct 2018 05:19:24 -0400 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id E341F8B841896; Tue, 16 Oct 2018 09:31:28 +0800 (CST) Received: from [127.0.0.1] (10.134.22.195) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.399.0; Tue, 16 Oct 2018 09:31:26 +0800 Subject: Re: [f2fs-dev] [PATCH] f2fs: clear cold data flag if IO is not counted To: Jaegeuk Kim CC: , References: <20181010212217.52289-1-jaegeuk@kernel.org> <3f08031e-d195-5bc1-67e1-f3b6eab3506b@huawei.com> <20181015230807.GC1296@jaegeuk-macbookpro.roam.corp.google.com> From: Chao Yu Message-ID: <405b1521-cbfb-9f09-0d16-ae837b756cbb@huawei.com> Date: Tue, 16 Oct 2018 09:31:25 +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: <20181015230807.GC1296@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 2018/10/16 7:08, Jaegeuk Kim wrote: > On 10/15, Chao Yu wrote: >> On 2018/10/11 5:22, Jaegeuk Kim wrote: >>> If we clear the cold data flag out of the writeback flow, we can miscount >>> -1 by end_io. >> >> I didn't get it, which count do you mean? > > It's the number of dirty pages. > > Balancing F2FS Async: > - IO (CP: 1, Data: -1, Flush: ( 0 0 1), Discard: ( 0 129304)) cmd: 0 undiscard: 0 > So I guess the race should be: GC thread: IRQ - move_data_page() - set_page_dirty() - clear_cold_data() - f2fs_write_end_io() - type = WB_DATA_TYPE(page); here, we get wrong type - dec_page_count(sbi, type); - f2fs_wait_on_page_writeback() How about relocate wait_writeback & set_page_dirty to avoid above race: move_data_page() retry: f2fs_wait_on_page_writeback(page, DATA, true); set_page_dirty(page); Thanks, >> >> Thanks, >> >>> >>> Signed-off-by: Jaegeuk Kim >>> --- >>> fs/f2fs/data.c | 4 ---- >>> 1 file changed, 4 deletions(-) >>> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index 29a9d3b8f709..4102799b5558 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -2636,10 +2636,6 @@ static int f2fs_set_data_page_dirty(struct page *page) >>> if (!PageUptodate(page)) >>> SetPageUptodate(page); >>> >>> - /* don't remain PG_checked flag which was set during GC */ >>> - if (is_cold_data(page)) >>> - clear_cold_data(page); >>> - >>> if (f2fs_is_atomic_file(inode) && !f2fs_is_commit_atomic_write(inode)) { >>> if (!IS_ATOMIC_WRITTEN_PAGE(page)) { >>> f2fs_register_inmem_page(inode, page); >>> > > . >