From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jared Hulbert" Subject: Re: vm/fs meetup in september? Date: Tue, 26 Jun 2007 10:07:24 -0700 Message-ID: <6934efce0706261007x5e402eebvc528d2d39abd03a3@mail.gmail.com> References: <20070624042345.GB20033@wotan.suse.de> <6934efce0706251708h7ab8d7dal6682def601a82073@mail.gmail.com> <20070626060528.GA15134@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: "Christoph Hellwig" , "Jared Hulbert" , "Nick Piggin" , "Linux Kernel Mailing List" , "Linux Memory Management List" , linux-fsdevel@vger.kernel.org Return-path: Received: from wa-out-1112.google.com ([209.85.146.176]:53535 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756389AbXFZRHZ (ORCPT ); Tue, 26 Jun 2007 13:07:25 -0400 Received: by wa-out-1112.google.com with SMTP id v27so2333946wah for ; Tue, 26 Jun 2007 10:07:24 -0700 (PDT) In-Reply-To: <20070626060528.GA15134@infradead.org> Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 6/25/07, Christoph Hellwig wrote: > On Mon, Jun 25, 2007 at 05:08:02PM -0700, Jared Hulbert wrote: > > -memory mappable swap file (I'm not sure if this one is appropriate > > for the proposed meeting) > > Please explain what this is supposed to mean. If you have a large array of a non-volatile semi-writeable memory such as a highspeed NOR Flash or some of the similar emerging technologies in a system. It would be useful to use that memory as an extension of RAM. One of the ways you could do that is allow pages to be swapped out to this memory. Once there these pages could be read directly, but would require a COW procedure on a write access. The reason why I think this may be a vm/fs topic is that the hardware makes writing to this memory efficiently a non-trivial operation that requires management just like a filesystem. Also it seems to me that there are probably overlaps between this topic and the recent filemap_xip.c discussions.