Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751533AbXBNKMQ (ORCPT ); Wed, 14 Feb 2007 05:12:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751534AbXBNKMQ (ORCPT ); Wed, 14 Feb 2007 05:12:16 -0500 Received: from relay.2ka.mipt.ru ([194.85.82.65]:43169 "EHLO 2ka.mipt.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751521AbXBNKMP (ORCPT ); Wed, 14 Feb 2007 05:12:15 -0500 Date: Wed, 14 Feb 2007 13:09:56 +0300 From: Evgeniy Polyakov To: Ingo Molnar Cc: Andi Kleen , linux-kernel@vger.kernel.org, Linus Torvalds , Arjan van de Ven , Christoph Hellwig , Andrew Morton , Alan Cox , Ulrich Drepper , Zach Brown , "David S. Miller" , Benjamin LaHaise , Suparna Bhattacharya , Davide Libenzi , Thomas Gleixner Subject: Re: [patch 05/11] syslets: core code Message-ID: <20070214100955.GA23702@2ka.mipt.ru> References: <20060529212109.GA2058@elte.hu> <20070213142035.GF638@elte.hu> <20070213222443.GH22104@elte.hu> <20070213223017.GJ29492@one.firstfloor.org> <20070213224131.GK22104@elte.hu> <20070214091348.GB4665@2ka.mipt.ru> <20070214094629.GA6801@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline In-Reply-To: <20070214094629.GA6801@elte.hu> User-Agent: Mutt/1.5.9i X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.7.5 (2ka.mipt.ru [0.0.0.0]); Wed, 14 Feb 2007 13:10:26 +0300 (MSK) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1038 Lines: 26 On Wed, Feb 14, 2007 at 10:46:29AM +0100, Ingo Molnar (mingo@elte.hu) wrote: > > * Evgeniy Polyakov wrote: > > > This will end up badly - I used the same approach in the early kevent > > days and was proven to have swapable memory for the ring. I think it > > would be much better to have userspace allocated ring and use > > copy_to_user() there. > > it is a userspace allocated ring - but pinned down by the kernel. That's a problem - 1000/512 pages per 'usual' thread ends up with the whole memory locked by malicious/stupid application (at least on Debian and Mandrake there is no locked memory limit by default). And if such a limit exists, this will hurt big-iron applications, which want to used high-order rings legitimely. > Ingo -- Evgeniy Polyakov - 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/