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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C7DAC67871 for ; Tue, 25 Oct 2022 02:52:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231315AbiJYCvp (ORCPT ); Mon, 24 Oct 2022 22:51:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229800AbiJYCvk (ORCPT ); Mon, 24 Oct 2022 22:51:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 525E810CFA9 for ; Mon, 24 Oct 2022 19:51:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E25E761717 for ; Tue, 25 Oct 2022 02:51:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C7D1C433C1; Tue, 25 Oct 2022 02:51:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666666298; bh=7DyQiRYGX5iB56h+VCaUyEKZGSQILTTmtLWCE7ekI1Y=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=O66ZC1UOs3IINrIKW1K/NMPMYa3qZ77OXjOYdQD1MJafjJTQqu2mkAzzpHlC3Qu0H aFxedUBT4fcW71hIHgNm0oGKhg7cDLfRTHlmjFhFox1G2FlmcW3zLQYObATzKbOSKR SsazqazQPPhjdkaCOqI33FBI/QBeO11GS0xqYE9tXbu39Osud66VVdrD0R1UNhaEJ4 iRdSR2SCSMX5i2jityCRBRrl3EmEGm8wAVNNjt16mOppuM7/jpEUTGRWmcFC+hn9RZ cs/xkbNbY7qWcpOzIK42zzwZAfEHT2tJ9FJdAMxKwoc2rqx+3ld0ew2cle8flSfoVe I+NI0Cqcwl5Fw== Message-ID: <429625d3-ca81-d067-deb7-e9d40725eaf0@kernel.org> Date: Tue, 25 Oct 2022 10:51:33 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 Subject: Re: [f2fs-dev] [PATCH] f2fs: make gc_idle sysfs node readable Content-Language: en-US To: Yangtao Li , jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <20221025023334.77096-1-frank.li@vivo.com> From: Chao Yu In-Reply-To: <20221025023334.77096-1-frank.li@vivo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/10/25 10:33, Yangtao Li wrote: > Hi Chao, > > What: /sys/fs/f2fs//gc_idle > Date: July 2013 > Contact: "Namjae Jeon" > Description: Controls the victim selection policy for garbage collection. > Setting gc_idle = 0(default) will disable this option. Setting: > > =========== =============================================== > gc_idle = 1 will select the Cost Benefit approach & setting > gc_idle = 2 will select the greedy approach & setting > gc_idle = 3 will select the age-threshold based approach. > =========== =============================================== > > From the kernel documentation, this node only describes the writing of > the value, and does not describe the reading of the value. If the value is used by userspace program, after the change, it will break userspace. > > Actually, this modification does the same thing as commit e60aeb2dee1a > ("f2fs: make gc_urgent and gc_segment_mode sysfs node readabl"). > I understand it is an addition to the omission of the patch above. > > Why gc_urgent and gc_segment_mode can be modified to string, but gc_idle > breaks forward compatibility? Oops, I guess that patch may have caused a regression...if there is any user.. > > Thanks,