From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH 2/2] cuse: implement memory mapping Date: Fri, 13 Jan 2012 10:19:50 -0800 Message-ID: References: <1326474399-27278-1-git-send-email-miklos@szeredi.hu> <1326474399-27278-3-git-send-email-miklos@szeredi.hu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wi0-f179.google.com (mail-wi0-f179.google.com [209.85.212.179]) by alsa0.perex.cz (Postfix) with ESMTP id B4B9E244F9 for ; Fri, 13 Jan 2012 19:20:12 +0100 (CET) Received: by wibhm6 with SMTP id hm6so632755wib.38 for ; Fri, 13 Jan 2012 10:20:11 -0800 (PST) In-Reply-To: <1326474399-27278-3-git-send-email-miklos@szeredi.hu> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Miklos Szeredi Cc: alsa-devel@alsa-project.org, htejun@gmail.com, mszeredi@suse.cz, gmane@colin.guthr.ie, linux-kernel@vger.kernel.org, smcnam@gmail.com, jamescaldwell1@gmail.com, linux-fsdevel@vger.kernel.org, s.maddox@lantizia.me.uk, david.henningsson@canonical.com List-Id: alsa-devel@alsa-project.org On Fri, Jan 13, 2012 at 9:06 AM, Miklos Szeredi wrote: > From: Tejun Heo > > This implements memory mapping of char devices. I don't think this is how you want to do it. It seems to maintain a page list of its own, and do the magic page fault etc behavior. Which to me smells like a really bad design. I would expect that what you actually want to do is to expose it as a shared mmap, and depend on all the normal shmem support. Is there any reason not to do that? I guess you don't generally have big mappings, so an argument like "that way you can page out pages etc" may not strike you as a very strong argument, but I'd still prefer to at least see that approach explored. Hmm? Linus