From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 6E61E6B01FA for ; Tue, 27 Apr 2010 07:52:31 -0400 (EDT) Subject: Re: Frontswap [PATCH 0/4] (was Transcendent Memory): overview In-Reply-To: Your message of "Sun, 25 Apr 2010 06:37:30 PDT." From: Valdis.Kletnieks@vt.edu References: <20100422134249.GA2963@ca-server1.us.oracle.com> <4BD06B31.9050306@redhat.com> <53c81c97-b30f-4081-91a1-7cef1879c6fa@default> <4BD07594.9080905@redhat.com> <4BD16D09.2030803@redhat.com> <4BD1A74A.2050003@redhat.com> <4830bd20-77b7-46c8-994b-8b4fa9a79d27@default> <4BD1B427.9010905@redhat.com> <4BD336CF.1000103@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1272369145_5118P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Tue, 27 Apr 2010 07:52:25 -0400 Message-ID: <72951.1272369145@localhost> Sender: owner-linux-mm@kvack.org To: Dan Magenheimer Cc: Avi Kivity , linux-kernel@vger.kernel.org, linux-mm@kvack.org, jeremy@goop.org, hugh.dickins@tiscali.co.uk, ngupta@vflare.org, JBeulich@novell.com, chris.mason@oracle.com, kurt.hackel@oracle.com, dave.mccracken@oracle.com, npiggin@suse.de, akpm@linux-foundation.org, riel@redhat.com List-ID: --==_Exmh_1272369145_5118P Content-Type: text/plain; charset=us-ascii On Sun, 25 Apr 2010 06:37:30 PDT, Dan Magenheimer said: > While I admit that I started this whole discussion by implying > that frontswap (and cleancache) might be useful for SSDs, I think > we are going far astray here. Frontswap is synchronous for a > reason: It uses real RAM, but RAM that is not directly addressable > by a (guest) kernel. Are there any production boxes that actually do this currently? I know IBM had 'expanded storage' on the 3090 series 20 years ago, haven't checked if the Z-series still do that. Was very cool at the time - supported 900+ users with 128M of main memory and 256M of expanded storage, because you got the first 3,000 or so page faults per second for almost free. Oh, and the 3090 had 2 special opcodes for "move page to/from expanded", so it was a very fast but still synchronous move (for whatever that's worth). --==_Exmh_1272369145_5118P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFL1s/5cC3lWbTT17ARAmumAKCHjFyFj3JFTplh2Gvlql0yTNIP+gCfdMBX OFkOMpZhtkWzYVdCP8d89Sw= =sCDE -----END PGP SIGNATURE----- --==_Exmh_1272369145_5118P-- -- 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