Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965155AbWHWTnf (ORCPT ); Wed, 23 Aug 2006 15:43:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965154AbWHWTnf (ORCPT ); Wed, 23 Aug 2006 15:43:35 -0400 Received: from relay.2ka.mipt.ru ([194.85.82.65]:38357 "EHLO 2ka.mipt.ru") by vger.kernel.org with ESMTP id S965152AbWHWTn1 (ORCPT ); Wed, 23 Aug 2006 15:43:27 -0400 Date: Wed, 23 Aug 2006 23:42:20 +0400 From: Evgeniy Polyakov To: Grzegorz Kulewski Cc: lkml , David Miller , Ulrich Drepper , Andrew Morton , netdev , Zach Brown , Christoph Hellwig Subject: Re: [take13 0/3] kevent: Generic event handling mechanism. Message-ID: <20060823194220.GA27685@2ka.mipt.ru> References: <11563322941645@2ka.mipt.ru> <20060823122509.GA5744@2ka.mipt.ru> <20060823134227.GC29056@2ka.mipt.ru> <20060823185624.GA8438@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline In-Reply-To: <20060823185624.GA8438@2ka.mipt.ru> 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, 23 Aug 2006 23:42:22 +0400 (MSD) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1380 Lines: 27 On Wed, Aug 23, 2006 at 10:56:24PM +0400, Evgeniy Polyakov (johnpol@2ka.mipt.ru) wrote: > > It can be done by selecting special event type, which in turn will reuse > > special fields as length. > > But variable-sized members can not be put into cache and without > > knowledge of it's size it is impossible to put htem into mapped buffer. > > And thinking more about this issue, I can say that I'm again > variable-sized structures - they can not be placed into ring buffer (at > least into simple one), they do not allow allocation from cache, it is > impossible to get them correctly from userspace if there is now exact > knowledge about nature of that events and a lot of other problems. > If one strongly feels that it is required, it is possible to provide > userspace pointer in the ukevent structure, which then can be read in > ->enqueue callback by kernelside (there is similar trick in network > AIO). I've reread my text - sorry for tons of errors, I use extremely slow GPRS link, so it is almost impossible to return and correct errors using it, I think it is simple to understand what I meant :) -- 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/