From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta8.messagelabs.com (mail6.bemta8.messagelabs.com [216.82.243.55]) by kanga.kvack.org (Postfix) with ESMTP id C1FE56B007E for ; Tue, 5 Jul 2011 13:25:45 -0400 (EDT) MIME-Version: 1.0 Message-ID: <6147447c-ecab-43ea-9b4a-1ff64b2089f0@default> Date: Tue, 5 Jul 2011 10:25:21 -0700 (PDT) From: Dan Magenheimer Subject: RE: [RFC] non-preemptible kernel socket for RAMster References: <4232c4b6-15be-42d8-be42-6e27f9188ce2@default D3F292ADF945FB49B35E96C94C2061B91257D65C@nsmail.netscout.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: "Loke, Chetan" , netdev@vger.kernel.org Cc: Konrad Wilk , linux-mm > From: Loke, Chetan [mailto:Chetan.Loke@netscout.com] > Sent: Tuesday, July 05, 2011 10:37 AM > To: Dan Magenheimer; netdev@vger.kernel.org > Cc: Konrad Wilk; linux-mm > Subject: RE: [RFC] non-preemptible kernel socket for RAMster >=20 > > In working on a kernel project called RAMster* (where RAM on a > > remote system may be used for clean page cache pages and for swap > > pages), I found I have need for a kernel socket to be used when >=20 > How is RAMster+swap different than NBD's (pending etc?)support for SWAP > over NBD? Hi Chetan -- Thanks for your question. I may be ignorant of details about NBD, but did some quick research using google. If I understand correctly, swap over NBD is still writing to a configured swap disk on the remote machine. RAMster is swapping to *RAM* on the remote machine. The idea is that most machines are very overprovisioned in RAM, and are rarely using all of their RAM, especially when a machine is (mostly) idle. In other words, the "max of the sums" of RAM usage on a group of machines is much lower than the "sum of the max" of RAM usage. So if the network is sufficiently faster than disk for moving a page of data, RAMster provides a significant performance improvement. OR RAMster may allow a significant reduction in the total amount of RAM across a data center. The version of RAMster I am working on now is really a proof-of-concept that works over sockets, using the ocfs2 cluster layer. One can easily envision a future "exo-fabric" which allows one machine to write to the RAM of another machine... for this future hardware, RAMster becomes much more interesting. Thanks, Dan -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org