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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 03932C433ED for ; Thu, 22 Apr 2021 06:51:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C68EA6145C for ; Thu, 22 Apr 2021 06:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234960AbhDVGvr (ORCPT ); Thu, 22 Apr 2021 02:51:47 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:16488 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234925AbhDVGvn (ORCPT ); Thu, 22 Apr 2021 02:51:43 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4FQp0r2Rqxzrdwb; Thu, 22 Apr 2021 14:48:44 +0800 (CST) Received: from [10.136.110.154] (10.136.110.154) by smtp.huawei.com (10.3.19.206) with Microsoft SMTP Server (TLS) id 14.3.498.0; Thu, 22 Apr 2021 14:51:04 +0800 Subject: Re: [PATCH] f2fs: compress: remove unneed check condition To: Jaegeuk Kim CC: , , References: <20210421083941.66371-1-yuchao0@huawei.com> From: Chao Yu Message-ID: <2c6f17e6-ef23-f313-5df2-6bd63d7df2b1@huawei.com> Date: Thu, 22 Apr 2021 14:51:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.136.110.154] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/4/22 12:04, Jaegeuk Kim wrote: > On 04/21, Chao Yu wrote: >> In only call path of __cluster_may_compress(), __f2fs_write_data_pages() >> has checked SBI_POR_DOING condition, and also cluster_may_compress() >> has checked CP_ERROR_FLAG condition, so remove redundant check condition >> in __cluster_may_compress() for cleanup. > > I think cp_error can get any time without synchronization. Is it safe to say > it's redundant? Yes, But no matter how late we check cp_error, cp_error can happen after our check points, it won't cause regression if we remove cp_error check there, because for compress write, it uses OPU, it won't overwrite any existed data in device. Seems it will be more appropriate to check cp_error in f2fs_write_compressed_pages() like we did in f2fs_write_single_data_page() rather than in __cluster_may_compress(). BTW, shouldn't we rename __cluster_may_compress() to cluster_beyond_filesize() for better readability? Thanks, > >> >> Signed-off-by: Chao Yu >> --- >> fs/f2fs/compress.c | 5 ----- >> 1 file changed, 5 deletions(-) >> >> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c >> index 3c9d797dbdd6..532c311e3a89 100644 >> --- a/fs/f2fs/compress.c >> +++ b/fs/f2fs/compress.c >> @@ -906,11 +906,6 @@ static bool __cluster_may_compress(struct compress_ctx *cc) >> >> f2fs_bug_on(sbi, !page); >> >> - if (unlikely(f2fs_cp_error(sbi))) >> - return false; >> - if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) >> - return false; >> - >> /* beyond EOF */ >> if (page->index >= nr_pages) >> return false; >> -- >> 2.29.2 > . >