Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757043Ab0HJDN6 (ORCPT ); Mon, 9 Aug 2010 23:13:58 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:40885 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755668Ab0HJDNw (ORCPT ); Mon, 9 Aug 2010 23:13:52 -0400 Date: Tue, 10 Aug 2010 12:12:06 +0900 (JST) X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Wu Fengguang Subject: Re: [PATCH 07/13] writeback: explicit low bound for vm.dirty_ratio Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , LKML , Peter Zijlstra , Dave Chinner , Christoph Hellwig , Mel Gorman , Chris Mason , Jens Axboe , Jan Kara , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" In-Reply-To: <20100806124452.GC4717@localhost> References: <20100805163401.e9754032.akpm@linux-foundation.org> <20100806124452.GC4717@localhost> Message-Id: <20100809235652.7113.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1095 Lines: 33 > Subject: writeback: explicit low bound for vm.dirty_ratio > From: Wu Fengguang > Date: Thu Jul 15 10:28:57 CST 2010 > > Force a user visible low bound of 5% for the vm.dirty_ratio interface. > > This is an interface change. When doing > > echo N > /proc/sys/vm/dirty_ratio > > where N < 5, the old behavior is pretend to accept the value, while > the new behavior is to reject it explicitly with -EINVAL. This will > possibly break user space if they checks the return value. Umm.. I dislike this change. Is there any good reason to refuse explicit admin's will? Why 1-4% is so bad? Internal clipping can be changed later but explicit error behavior is hard to change later. personally I prefer to - accept all value, or - clipping value in dirty_ratio_handler Both don't have explicit ABI change. Thanks. -- 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/