Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753718AbaBDBsM (ORCPT ); Mon, 3 Feb 2014 20:48:12 -0500 Received: from sh.osrg.net ([192.16.179.4]:59867 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752388AbaBDBsK (ORCPT ); Mon, 3 Feb 2014 20:48:10 -0500 Date: Tue, 04 Feb 2014 10:47:56 +0900 (JST) Message-Id: <20140204.104756.212377853.konishi.ryusuke@lab.ntt.co.jp> To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-nilfs@vger.kernel.org, Andreas Rohner Subject: Re: [PATCH 4/4] nilfs2: implementation of NILFS_IOCTL_SET_SUINFO ioctl From: Ryusuke Konishi In-Reply-To: <20140203134101.c56b916544e2475f63227339@linux-foundation.org> References: <1391446244-1435-1-git-send-email-konishi.ryusuke@lab.ntt.co.jp> <1391446244-1435-5-git-send-email-konishi.ryusuke@lab.ntt.co.jp> <20140203134101.c56b916544e2475f63227339@linux-foundation.org> X-Mailer: Mew version 6.3 on Emacs 23.2 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.3.9 (sh.osrg.net [192.16.179.4]); Tue, 04 Feb 2014 10:47:57 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 3 Feb 2014 13:41:01 -0800, Andrew Morton wrote: > On Tue, 4 Feb 2014 01:50:44 +0900 Ryusuke Konishi wrote: > >> With this ioctl the segment usage entries in the SUFILE can be >> updated from userspace. >> >> This is useful, because it allows the userspace GC to modify and update >> segment usage entries for specific segments, which enables it to avoid >> unnecessary write operations. >> >> If a segment needs to be cleaned, but there is no or very little >> reclaimable space in it, the cleaning operation basically degrades to >> a useless moving operation. In the end the only thing that changes is >> the location of the data and a timestamp in the segment usage >> information. With this ioctl the GC can skip the cleaning and update >> the segment usage entries directly instead. >> >> This is basically a shortcut to cleaning the segment. It is still >> necessary to read the segment summary information, but the writing of >> the live blocks can be skipped if it's not worth it. > > Documentation/filesystems/nilfs2.txt should be updated to document the > new ioctl. > > Which we're in there, please check that the ioctl documentation is > otherwise complete and up-to-date. These things have a tendency to > bitrot. Got it. I missed the recent effort by Vyacheslav which added description on every ioctl in the doucument file. I'll send a patch for this soon. Thanks, Ryusuke Konishi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/