From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 30 Jan 2008 16:39:27 -0800 From: Andrew Morton Subject: Re: [patch 6/6] mm: bdi: allow setting a maximum for the bdi dirty limit Message-Id: <20080130163927.760e94cc.akpm@linux-foundation.org> In-Reply-To: <20080129154954.275142755@szeredi.hu> References: <20080129154900.145303789@szeredi.hu> <20080129154954.275142755@szeredi.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Miklos Szeredi Cc: a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org List-ID: On Tue, 29 Jan 2008 16:49:06 +0100 Miklos Szeredi wrote: > Add "max_ratio" to /sys/class/bdi. This indicates the maximum > percentage of the global dirty threshold allocated to this bdi. Maybe I'm having a stupid day, but I don't understand the semantics of this min and max at all. I've read the code, and I've read the comments (well, I've hunted for some) and I've read the docs. I really don't know how anyone could use this in its current state without doing a lot of code-reading and complex experimentation. All of which would be unneeded if this tunable was properly documented. So. Please provide adequate documentation for this tunable. I'd suggest that it be pitched at the level of a reasonably competent system operator. It should help them understand why the tunable exists, why they might choose to alter it, and what effects they can expect to see. Hopefully a reaonably competent kernel developer can then understand it too. -- 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