Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933298Ab0D3R3L (ORCPT ); Fri, 30 Apr 2010 13:29:11 -0400 Received: from ksp.mff.cuni.cz ([195.113.26.206]:60712 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758706Ab0D3R2o (ORCPT ); Fri, 30 Apr 2010 13:28:44 -0400 Date: Thu, 29 Apr 2010 15:02:31 +0200 From: Pavel Machek 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 Subject: Re: Frontswap [PATCH 0/4] (was Transcendent Memory): overview Message-ID: <20100429130231.GA1661@ucw.cz> References: <4BD1A74A.2050003@redhat.com> <4830bd20-77b7-46c8-994b-8b4fa9a79d27@default> <4BD1B427.9010905@redhat.com> <4BD336CF.1000103@redhat.com> <4BD43182.1040508@redhat.com> <7264e3c0-15fe-4b70-a3d8-2c36a2b934df@default20100427125624.GB3681@ucw.cz> <36b23d5c-ca25-44b5-be9f-b7ceaab0dd2e@default> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <36b23d5c-ca25-44b5-be9f-b7ceaab0dd2e@default> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1135 Lines: 30 Hi! > > Stop right here. Instead of improving existing swap api, you just > > create one because it is less work. > > > > We do not want apis to cummulate; please just fix the existing one. > > > If we added all the apis that worked when proposed, we'd have > > unmaintanable mess by about 1996. > > > > Why can't frontswap just use existing swap api? > > Hi Pavel! > > The existing swap API as it stands is inadequate for an efficient > synchronous interface (e.g. for swapping to RAM). Both Nitin > and I independently have found this to be true. But swap-to-RAM So... how much slower is swapping to RAM over current interface when compared to proposed interface, and how much is that slower than just using the memory directly? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/