From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id C0CDF600044 for ; Mon, 9 Aug 2010 23:12:56 -0400 (EDT) Date: Tue, 10 Aug 2010 12:12:06 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 07/13] writeback: explicit low bound for vm.dirty_ratio 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 Sender: owner-linux-mm@kvack.org To: Wu Fengguang 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" List-ID: > 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org